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The ABC Suspension Thread

 
Old 12-27-2015, 02:57 PM
  #26  
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Procedure/action list when ABC has issue or ABC message show up.

https://mbworld.org/forums/s-class-w...ml#post5376771

Haven't has issues after all my repair and preventative maintenance after purchase. When hanging around saw ABC car owner has ABC issues which cost a lot to fix. Actually some of them could aviod spending big $$ if acted properly when have the issue.

Base on my understanding with ABC, not anything official, here is a general procedure/action list to follow when ABC issue happen, for example when ABC message lit, a big bang under the hood like high pressure line exploded, or smell of Pentosin:
1) Pull over when in traffic, stop the car asap when safe to do so.
This will save your pump if only a hose broke or o-ring gone. The ABC pump keeps running when engine is on. It need hydraulic fluid for lubrication. It is safe to run for only a short time, let's say 1 min, not guaranteed, with fluid left to lubricate. For any prolonged period it will die for sure without fluid coming in.
2) Write down the warning msg for later reference, check for any fluid leakage and struts level. Then check ABC fluid level.
3) Try not to re-start the car hoping it will be fine. Only start the car when you have a solution or you have to.
4) If you have no idea about what is happening then have the car towed and checked.
5) If car level is fine, no fluid leakage, ABC fluid level is fine and only get white ABC msg. You can drive to have it checked.
6) If any of the checking in 2) failed there is risk keep driving:
- Car level is not good, one or more corner is too low, there is risk for fender damage and car handles poorly. In case you have to drive, drive slowly avoid tight turn or uneven road.
- Fluid leaking or ABC fluid level is low. You may lose the pump and pressure due to lack of lubrication.
- Any red ABC msg is bad news and should be treated carefully and immediately.
7) If struts level are all fine and in case you insist driving don't raise or lower the car since you may not be able to raise it anymore. Again you may lose the pump if there is no lubrication.
8) If you have to drive a short period and there is no fluid. To save the pump you may want to take the belt off. But this is not proved to be safe as you won't have power steering, Coolant pump or Generator. When drive without the belt, turn off all electrics and keep monitoring engine temperature. Again this is not a proven method and use it on your own risk.

Thanks.

Howard

Last edited by Welwynnick; 12-27-2015 at 05:42 PM.
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Old 12-27-2015, 03:03 PM
  #27  
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Discovering my first ABC hose leak

https://mbworld.org/forums/s-class-w...ml#post5479321

I was kind of hoping that my leak WAS in the front valve block, as that's the sort of repair I'm comfortable with (I've stripped down power steering racks before now). However, I think my problem is not what I wanted it to be. It looks like I simply have a burst pipe - the one in front of the engine that doesn't seem to go anywhere. I tried taking lots of pictures, but had a great deal of difficulty getting anything useful. The first is a vertical view down the front of the engine - main pulley on the right and rad on the left. The broken pipe is smack in the middle. You can see that the hose has completely come out of the joint.

The second is a view from underneath; subframe on the left, radiator fan on the right, two pipes in the middle, and the broken one just above them in the center:

Everything is obviously covered in oil (and rain). You can't see from those pictures that that pipe turns under the engine and heads rearwards. I'm not sure where it comes out (its not clear from all the ABC diagrams I've seem on MBW) but it seems to be at the pressure regulator / damper near the steering rack. Is this the vibration damper pipe that I hear people talking about?

It would seem to be rather inaccessible. I've got a bad feeling about this. Can someone put me out of my misery?

Thanks, nick



Last edited by Welwynnick; 12-27-2015 at 05:43 PM.
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Old 12-27-2015, 03:05 PM
  #28  
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Hello Nick and Howard,

I'm familiar with the pulsation damper hose which burst on your car.
From the capped end it runs toward the passenger side horizontally, then appears to turn rearward just as it goes past the crankshaft pulley. However it actually does a U-turn there and goes back toward the driver side, then up to the ABC pump. The high pressure output of the pump is a banjo bolt on the underside of the pump and there are two banjos stacked, through which passes the single banjo bolt. The end of your popped hose is the lower of the two stacked banjos.

I cannot warrant the following, but when I examined the routing during a recent ABC pump replacement on my 2004 S600 TT, it appeared to me that I would be able to replace this hose without raising the engine at all, the most difficult part being the tight ratchet access to the banjo bolt from under the front side of the pump, just as had to be done during the pump replacement.

BTW, for anyone contemplating pump replacement, I can offer two very helpful tips in hindsight.
First, for the banjo bolt, use a 3/8" ratchet which has extra fine teeth in the ratcheting mechanism i.e. small angle between clicks, and with minimum backlash. This seemed even more essential for the reassembly compared to the dis-assembly. Secondly for the 10mm e-torx bolt which fastens the pump from the rear side, it may be easier to turn with an e-torx box end wrench having a vertical offset, i.e. an S-shaped bend in the shank near the box end, as viewed from the side of the wrench. I didn't have one, so I had to use a 10mm e-torx socket clamped in vise grips to get the offset, and turning and re-clamping the socket 1/12 revolution each time. None of my 3/8" ratchets would fit into the available space.

Should you find the part number for this pulsation damper hose, kindly post it here because I would like to get one to have on hand.

Good luck,

Drew
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Old 12-27-2015, 03:08 PM
  #29  
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Thanks for the advice Drew, really appreciate it. Would you recommend removing the poly-V belt as well?

After removing the fan and serpentine belt, the pump does turn smoothly and firmly.
It spins round easily enough, but stops immediately.
It was replaced by a previous owner, and it definitely feels new rather than knackered.

I've been looking around for a new damper pipe, and I'm wondering what's really required of it.
After dipping into hydraulics a bit (a new field for me),this is a quick summary of what I found:
It seems that ABC is mostly a conservative, conventional system.
200 - 300 bar is normal working pressure for industrial hydraulics.
They're proof tested to 2x that, and expected to fail at 4x.
Small bore pipes commonly have two layers of steel braid, and cost a few pounds per metre.
End fittings cost a few pounds, and the swaging ferrules are pennies.
Swaging machines (which can press tens of tons) are expensive, but there are lots of companies that service and repair hydraulics.
New pipes take a few minutes to make, and generally cost a few tens of pounds - about a tenth of what Mercedes charge.
Industrial pumps, pipes, valves and telescopic rams are relatively cheap and easy to repair.
My impression is that they're INTENDED to be serviced and repaired periodically.

ABC hydraulics, by contrast, are tightly packaged into hot, vibrating, corrosive environments, but are "intended" to be fitted for life.
It shouldn't have been difficult to see that it wouldn't work out like that.
I think Mercedes should have designed the system to have been more maintainable.
However, looking at the V12TT engine bay, its hard to see how they could have done anything else.
At least they didn't make Lexus' mistake and mount the suspension pump directly above the alternator.....

I'm struggling to understand the requirment for the damper pipe. It looks like an afterthought of the development process. If its just there to damp pressure pulses, then I could presumably get someone to make a terminated 2 ft hose, and route it somewhere convenient. Alternatively, maybe I could connect a reservoir sphere to the end of a short pipe. On the W216/W221 ABC pumps, it looks like Mercedes HAVE added a sphere to the pump itself - they probably wish they'd done that all along with the earlier cars, but that's the price you pay for being a technology pioneer....

Nick
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Old 12-27-2015, 03:09 PM
  #30  
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Drew, you're right on the money. Removing the fan and poly-V belt isn't difficult (you do have to take care) but I think its quite essential to getting adequate access down there.

The socket wrench was good advice, too. My trusty 1/2" wrench wouldn't even go in there. I have a decades-old 3/8 socket set, but the wrench has something like 40/48 teeth, and that's too coarse to ratchet in the space available. I went out and bought an expensive 72-tooth wrench. Its a pleasure to use and does the job perfectly. For anyone who wants to remove these pipes or the pump, I'd say plan a little further ahead than I did and buy a 72-tooth wrench online for a modest amount, and don't even think about proceeding until you've done so. Its a no brainer.

I got the burst vibration damper pipe out and went looking for spares or repairs. I didn't hold out much hope of avoiding spending hundreds at the dealer, until I found a hydraulics/pneumatics workshop a few miles from home. On the phone, they said don't repair hydraulic pipes, as used flexible hoses cannot be re-terminated, which is something to bear in mind. A new one sounded fine to me, so I went down there and had a good time looking at the guy's face as he tried to work out what he was looking at. It was a picture, until I explained what it did.

The bent-pipe fittings are Mercedes proprietary, so he couldn't make anything EXACTLY the same, but he did suggest cutting the end of the metal pipe, putting a compression fitting on the end, and adding a terminated flexible hose to replace the failed section. The termination would be removable, so as to bleed the pipe. Nice. He did that while I waited, and it only took a few minutes. This all proved the worth of getting the part into the hands of someone who knows what they're doing, and has done it every day for a long time.

I pushed my luck and picked his brains about hydraulics in general, and what Mercedes had done in this instance, and he was happy to chat for a while. It seems that there's nothing special about the hardware, the pipes are what they call two-wire (twin layers of steel braid within the rubber hoses) which is typical for run-of-the-mill hydraulics. These pipes and fittings typically run at 300 bar, with ABC at the low end of commercial hydraulic systems pressures. He gave me some O-rings to replace the slightly squashed ones that came out of the banjo fittings, but was quite confident that I could use cheap nitrile O-rings from a large box-set that he dipped into for all his other customers. Do a search for "419 piece O-ring set", and you find what he used.

There was nothing challenging about doing this repair, and even finding this workshop was easy. For anyone in the UK, the chain is called Hopespare, and I thoroughly recommend them. There are lots of workshops around, and it was all very painless compared to going to a dealer. Best of all, he only charged me £39, and this is what I got:

The ABC Suspension Thread-p1010272_zps7a24f94b.jpg

Nick

Last edited by Welwynnick; 12-27-2015 at 04:31 PM.
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Old 12-27-2015, 03:13 PM
  #31  
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https://mbworld.org/forums/s-class-w...ml#post5493889

I've now re-fitted my repaired damper pipe today (fine-tooth wrench earned it's worth), and I'm working on bleeding the system, and I have a cunning idea...

There's a clear consensus that to bleed the ABC, you need to pressurize the fluid reservoir to prime the pump - otherwise the pump won't suck up the oil (for some reason). So I was wondering how I was going to pump up the reservoir... Since I now have a removable blank at the end of my damper, and with the serpentine belt still off, I thought I'd fill the reservoir and try to get oil through the damper simply by spinning the pump by hand. Maybe by turning it relatively slowly, I could prime the pump? No harm done if it DIDN'T work, but it would show that the pump WAS primed if it DID work. Does the logic make sense?

And what happened when I spun the pump? Well - after a little while - oil came out the end of the damper! I pumped it by hand for a while, until I was happy that the pump and damper were full of oil, then I closed off the termination at the end of the damper. I was happy with doing that, as it gave me confidence that the pump was primed. Then I filled up the reservoir again, disconnected the return pipe, pushed a few feet of clear PVC tubing into the end, and started the engine. To my relief, oil spurted out of the pipe straight away, and I ran a few litres through to flush the system. I wasn't brave enough to fill the reservoir continuously while the engine was running; I just started and stopped the engine a few times. The cold engine was idling fast, and the reservoir seemed to empty quickly. I was pleasantly surprised to see that the oil I was flushing out was clean, clear and green. So four litres later I stopped the engine and closed everything up.

So, very pleased and quite confident with a day's work.

Nick
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Old 12-27-2015, 03:14 PM
  #32  
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Lessons Learned

I drove my TT to work this morning with some apprehension, but no leaks or alerts. It was off the road for a long time, but next time will be different. My rule of thumb is ďhalf the time the second timeĒ, and thatís probably conservative. I now have a spare car which I can use whenever I want Ė but should I have to?

This is my fourth W220, and the third with ABC. Previously, my approach to dealing with ABC had been to cross my fingers and hope for the best. But Iím rather more confident to diagnose and tackle any problems now, rather than throwing a bag of money at a dealer. Things like pumps and struts will always be expensive, but many faults are readily repairable. And you have to accept that they WILL happen.

I was working outside, to give me better light and more space, but this was a mistake. The weather wasnít great, and that tended to keep me inside, rather than getting on with it. Iíll use the garage next time, and Iím still planning to get a four-post ramp soon. I would positively look forwards to working on cars if I had one of those. I never realised what they cost before, and wish Iíd got one ten years agoÖ..

Since the car was nose-down on one wheel, Iíd assumed that the problem was with the valve assembly, and didnít notice the obvious fault at first. If there was a fault upstream of the control valves, I assumed that all corners would be low, rather than just one. Thereís a lot you can do to manage ABC and diagnose faults, but it still pays not to jump to conclusions.

Removing all the parts necessary to get full access was half the game. I went overboard and removed all the wheel arch liners and the front bumper. (This was partly out of curiosity Ė I had long wanted to see if I could squeeze a larger charge cooler radiator in there) The trick is to know what to remove and what to leave. In general, DONíT lift the engine, but DO remove the fan and drive belt. The oil reservoirs and coil pack can stay put for the vibration damper, but probably need to come out for the ABC pump itself.

Finally, I have to confess that my ABC did give me some advance warning, and Iíd stuck my head in the sand. There was a small leak at the front, and I should have done something about it. I lost the use of my car for a few weeks, but it might have been worse; I could have been on holiday with the family. In future Iíll inspect everything closely and act on advance warnings.

Nick
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Old 12-27-2015, 03:19 PM
  #33  
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M022 ABC high pressure lines/hoses replace

Put new brake pads in the front when switching to all season tires.
At the same time inspected the car and found four ABC hoses are wet.
When those high pressure hoses are old the rubber deteriorate and the hoses start weeping. Most of the time it is from the fitting connection.
At the very beginning the weepage is small and doesn't affect driving. But if it is ignored finally the hose will give up and burst which will cause serious problems.

Many forum members had ABC hose burst and stranded on the road. This could be dangerous on the highway and, in some cases, lead to pump replacement.

According to above facts I use the weepage as a warning and replace hoses in question.

There are 10 high pressure lines/hoses in ABC:
1) Pulsation damper: directly connected to tandem pump through banjo and has two rubber hose sections;
2,3) Pressure lines from pump to PSV(Pressure Supply Valve), 1st part and 2nd part:
4) Pressure lines from PSV to split point:
5,6) 2 Pressure lines from split point go to front and rear valve blocks;
7,8,9,10) 4 Pressure lines from valve blocks to 4 struts;
In my case, 1,3,4,7 are wet and will be replaced.

According to Nick and Drewk88's experience I didn't buy OEM lines. As mentioned some lines are just too hard to remove. Instead I cut the rubber section including the fitting and had a hydraulic shop make the rubber hose with proper fitting. Then I connect the new hose to the original metal line. This way I could always easily replace those rubber sections in the future when they have signs of going bad. Please see picture 1 for new and old hose compare, and picture2 for all the new hoses.

I followed Drewk88's instruction for replacing the pulsation damper it worked well. In addition I raise the engine 1 to 2 inches which made putting in the damper and aligning the banjo bolt easier. As Drewk88 mentioned I access the banjo bolt from the front of the pump by using a fine teeth wrench.
Before I could work on the banjo bolt I did remove the following:
- fan shroud;
- v belt;
- ABC pump pulley;
- ABC/Steering reservoir;
Please see picture 3 for the old pulsation damper and picture 4 for the new one which is already in place.

Other hoses are easier than the damper, please see picture 5 for the PSV and picture 6 for the 2 high pressure lines attached to the PSV.

I asked the shop to use high quality hoses and fittings. 4800 psi system were chosen (include hose, compression fitting, ferrule, locking nut) which is significant higher than the ABC working pressure (3000 psi). The damper was made pretty well. I was worried about putting the damper back will be hard as in such a tiny space even a little bit size variation will make the damper impossible to fit. Any way the result is good. Other hoses are good as well.
Make sure to use insulation material and foil to wrap the rubber hoses which are near the exhaust. This reduce the heat to the hose and prevent oil getting to the exhaust in case it weeps again.

After connecting all hoses back, performed the routine to restart the tandem pump:
- Pour enough Pentosin in both ABC and Steering reservoirs;
- Pre-pressurize ABC reservoir to make sure pump get oil;
- Start the engine and hit ABC raise vehicle switch, wait for 10 second, stop the car and add ABC fluid;
- Start the car again and check all new lines for leaking;
- Drive the car then check oil level and lines for leaking;
So far so good.

Cost:
$500 for making the lines/hoses;
$50 for new o-rings and other parts;

More than 20 hours work not include making the hoses.


Howard

Last edited by Welwynnick; 12-27-2015 at 04:29 PM.
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Old 12-27-2015, 03:22 PM
  #34  
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I009 ABC maintenance guidelines

This post is compiled base on many forum members' experience and contribution under this topic: Welwynnick, Drewk88, Eric242340...
The purpose is to help ABC owner to increase the ABC reliability and reduce the owning cost. You could find the ABC is never problematic if you follow the maintenance suggestions.
As usual, all the suggestions are base on my experiment and knowledge, hence not official, please use them with your own judgement.

There are many occasions that ABC failed and cost the owner a lot to fix. Even worse, some of the problems happen again and again.
After reviewed and researched some cases it come to a conclusion that most of the ABC issues are preventable if we do regular maintenance.

That said, to keep ABC in a good shape and keep ABC cost reasonable, you have to do regular maintenance.
Why, we do regular maintenance on engine, transmission, transfer case, differential, etc... Why not ABC ?
E.g. if you leave the fluid in transmission as 'sealed for life', you tranny won't last. ABC won't either.
If you can DIY, that's good. If not, insist your mechanic or your dealer to do the ABC regular maintenance for you.

Ok, stuff you need to take care:
1, Visual check ABC components, lines/hoses and fluid level during every A/B maintenance. Fix leaking or other issue promptly.

2, Regular fluid and filter replace: ABC is a hydraulic system which contain 4 liters of Petosin chf 11S.
- Please replace the fluid/filter on a regular basis, let's say every 30kMiles/50kKm.
- The ABC fluid has its life span just like engine oil, transmission fluid, etc...
- As the fluid degraded/contaminated the internal parts in ABC (pump, valve body, strut...) will rust, accumulate deposit or get clogged
- Water contamination is a common but serious problem in Hydraulic industry. It is a critical and regular process to maintain hydraulic fluid in those heavy equipment.
- A simple way is to syphon/empty the ABC reservoir then fill with new fluid and replace the filter. Within a week or two adjust height often for better circulation. Then syphon/empty and refill the reservoir 2nd time. This way most of the fluid is refreshed.
- There will be some old fluid left in the hoses and struts, but it is good enough if you don't have any symptom.
- If you have lowered corner issue, you may need a rodeo to flush the system, again rodeo/flush is not necessary for regular fluid replacement.
- Be sure to change the ABC filter now if you still have the original ABC filter. The original filter is 10 micros and the new filter is 3 micros.
- Here I documented my fluid/filter replace, not simple version, but have some information could be referenced:Ongoing Maintenance and Repair for a 2003 S600.

3, ABC lines/hoses replace. There are rubber hydraulic hoses in the ABC system. Hoses need to be replace when it is weeping oil, otherwise it will exploded finally.
- Hydraulic hoses are made from rubber which will deteriorate for sure. Especially true for ABC which is constantly running under heat and pressure.
- There is no rubber hose build for life. But the hoses will not explode without symptom either. There is plenty of time to identify the weeping hose before it gives up.
- Check and replace hydraulic hoses in the Hydraulic industry is a common practice. Leave the hoses unattended will lead to hose rupture and disaster.
- Check or have your mechanic to inspect every ABC lines/hoses during the A/B maintenance. Replace the line/hose which is wet or weeping.
- For DIYer we found a practical and cheaper way to replace hydraulic lines/hoses. Follow hydraulic industry regular process, we made our own hoses, which is cheaper. And we modify the line/hose and use standard hydraulic hose compression fitting to make the hose replace much easier, more like a plumber. Please see the process documented:
Ongoing Maintenance and Repair for a 2003 S600.
Above is the regular maintenance you need to follow. Below are more information to help you handle ABC related issues.

4, ABC action list. For each ABC owner please familiar yourself with the list and have it handy. It will help you diagnose and react correctly in case you have ABC issue: Ongoing Maintenance and Repair for a 2003 S600.

5, For lowered corner issue: Most of the time it is the Valve Block internal leaking, replace o-ring is the first and cheap way to fix:
Ongoing Maintenance and Repair for a 2003 S600.

All in all, ABC is a great system combined with sensors, computer and hydraulic system which provide a superb ride quality. There is no fatal design and build issue as many guessed in the system and the ABC is continued to be used as the core of the MBC(Magic Body Control).
I also understand there are unpleasant experience related to ABC. It is caused by one lost link in the chain: regular maintenance. There is no clear maintenance schedule for ABC and the dealer is lack of knowledge of maintaining hydraulic system too, as Hydraulic is another industry.
There are so many different kind of hydraulic systems in heavy equipment/vehicles. They are reliable, dependable and reasonable in owning cost because they are well maintained. ABC should be one of them.

Again, don't neglect the ABC. It is our, owners', responsibility making sure regular/preventative maintenance is done. Not just replace fluid when it acts up, at that time it is already too late. Check hydraulic lines/hoses regularly and replace any in question. In the Hydraulic industry everyone does this, why not for ABC. Do not wait for the hose to explode, there is risk when you are driving although the shutoff valve will protect the system and keep the strut height. As a concequence, the system is open and you lost fluid which lead to pump failure. $200 hose triger a $2000 pump failure. When the pump failed it may pump metal into your system messing up everything... Do not let this happen.

All in all, I hope the information gathered here could bring attention to you that regular maintenance is a must for ABC, plus to clarify any confusion you want to know about this unique suspension system.

Thanks.

Howard

Last edited by Welwynnick; 12-27-2015 at 04:30 PM.
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Old 12-27-2015, 03:38 PM
  #35  
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There's nothing like learning things the hard way so you don't forget, but at least with this thread we can pool our experience and help other people steer clear of avoidable ABC pitfalls. So here's a few more things I've learned:

1. The "bleed nipples" that are actually used for draining each leg of the solid pipes leading to each strut, tend to rust and seize over time. Whenever you have cause to undo the nipples, I suggest replacing them with new ones as a matter of course. Get a stock of them.

2. The ride height at each corner is measured with a lever arm sensor, connected to the respective wishbone with a short link. The links have ball-joints at each end which corrode and seize. On my car, a seized joint led to the small mounting bracket itself providing the necessary articulation, so it failed. I strongly recommend checking the link ball joints, say every year or so. Its not a catastrophe in the making, but it could really spoil your day.

3. On the W220, the front struts are mounted to the ball joints in the track arms with a peculiar flanged spigot that's secured with a torx grub screw. Can't imagine who could have thought of that. Obviously, that seizes as well, which stops you removing the strut in the intended manner (and you will need to remove a strut or two at some time). I suggest removing and cleaning up the screws every few years. The W221 has a much better arrangement, and the rear struts are much more straightforward.

4. Finally, most avoidable of all, each strut has a quick-release hydraulic connection at the end of the hard lines. Hydraulically its very robust, but its really a dumb idea as the collar always seizes. Ultimately you can free the collars with pliers, but it takes hours rather than seconds. When the weight is on the wheels, the hydraulic pressure holds the joint tight, but if you raise the car you can rotate the collar to keep it free.

5. And as always, never drive with red warnings or an empty ABC reservoir.

Best of luck,

Nick

Last edited by Welwynnick; 12-27-2015 at 04:28 PM.
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Old 12-27-2015, 04:27 PM
  #36  
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Balljoints

https://mbworld.org/forums/s-class-w...ml#post5936896

I thought I'd mention a couple of hours that were well spent yesterday. My car has done a high mileage and the suspension is pretty tired. It squeaks when I get into it, and it squeaks over bumps; pretty embarassing really.

I narrowed it down to the balljoint at the bottom of the RHS rear strut, so I disconnected the strut and the lower arm, and eased the strut back.
The balljoint has rubber boots, and I removed the circular retaining clips.
Everything was very dirty, so I cleaned it all out and re-packed it with grease, then wobbled and spun the balljoint round many times to spread the grease.
Refitting the rubber boot was tricky, but it all went back together.
The strut mounting goes back in first - its easy if you hold the lower arm DOWN with a lever.
Then the lower arm is reconnected to the suspension upright - its easy if you lift the lower arm UP with a jack.
The bolts are big - you need 21mm or 13/16 tools, E-Torx sockets, and big levers.

If you need to remove a strut for any reason, that would be a good time to do it.
I drove to work this morning, and all the noises went away. I was never as happy with the ride of my current V12TT as I was with my previous V12NA, but this went a long way to redressing the difference - its a different car.

Sorry, no pictures, I had very dirty hands and it was getting late.
Anyway - very worthwhile.

Nick
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Old 12-27-2015, 04:36 PM
  #37  
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https://mbworld.org/forums/s-class-w...ml#post6084025


I found an interesting Hydraulic Systems Manual by Parker today:

http://www.google.co.uk/url?sa=t&rct...69620078,d.ZWU

So with thanks to parker, here are some interesting quotes:

Excerpt DIN 20066:2002-10:
For the production of hose assemblies the hose (bulk hose) must be younger than 4 years according to the hoses date of manufacture. The service life of a hose assembly, including any period of storage should not exceed 6 years; the period of storage should not exceed 2 of these 6 years.




Additionally, the International Standard Organisation (ISO) has prepared a draft version of a guideline for hose/hose assembly usage that differs slightly from the German guideline. The ISO/TR 17165-2 states that the shelf life of hose as bulk hose or as hose made of 2 or more materials should not exceed ...10 years... from the date of manufacture of the hose if stored in accordance with ISO 2230 (ie: cool, dry, clean, dark)




In general the combination of high temperatures and high pressures reduce the service life of the hose. More regular inspection of the hose assemblies should be carried out to assure the continued safe functionality of the hose assembly.






Modern hydraulic equipment is becoming highly precise and as such more sensitive, so as a result the importance of a clean working fluid in the system is growing. Because as many as 75% of hydraulic system failures are caused by contamination of the fluid by solid particles, the initial cleanliness of hydraulic components, as the main source of these contaminates, is vital.




There's an interesting section on temperature as well. It stands to reason that over=-heated hoses fail more quickly, but I haven't seen anything to quantify this. Well, medium and high-pressure hoses are usually rated to working pressure at up to around 100 deg C. There's a non-linear de-rating of max working npressure at higher temperatures, but the short version is that you get 100% working pressure (say 300 bar) at 100 deg C, and that derates down to ZERO by 150 deg C.

I'm not sure what the under-hood temperatures are, but I bet they're usually close to 100 deg C, and often go higher - a lot higher with the V12TT! I reckon that gives all the non-metal parts like hoses, motor mounts and coilpacks a hard time. I found out recently that my S600TT has air-cooled motor mounts - that's what the NACA ducts on the under-tray are for. I never realised that until I dropped the front subframe.

I just removed six ABC hoses from my engine compartment, including the one the goes under the engine, and have a few interesting pictures and observations to make.

Nick


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Old 12-27-2015, 04:39 PM
  #38  
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ABC Hose Insulation

https://mbworld.org/forums/s-class-w...ml#post6084111


These are the six ABC hoses that I removed from around the engine compartment. I'm zooming in on that area as there are three potential causes of premature hose failure that I'm homing in on:

High working pressure (ie: feed lines, rather than return lines, which never fail)
High ambient temperature (hoses often fail in and around the engine)
Unprotected hoses (MB already protects the hoses in the hottest locations)

IMAG1031_zps337e0d3e.jpg?t=1403730623

The two hoses top right are the pump output and the early type vibration dampener, which both run across the front of the engine.
The two hoses in the middle are the pressure regulator outputs, which run back across behind the engine, where the sway bar used to go.
The pipe on the left is the bogey pipe that goes under the engine, and feeds the pressure regulator.

I cleaned up all the metal pipework and pipe covers, but I left the hoses untouched so I could take these pictures.


IMAG1038_zps87dad504.jpg?t=1403730653

This is a close-up of the two regulator output pipes. I guess they were considered to be vulnerable to hot air exiting the rear of the engine compartment, and they are protected by these aluminised fibreglass sleeves. As you can see, the hoses are in good condition. Since I have a rare opportunity to access everything at the moment, I'm going to replace them as a precaution. This also gives me the opportunity to get some compression connections at the ends of each hose, so they're easy to replace in future (as Mercedes should have done).

IMAG1036_zps0c7d3972.jpg?t=1403730673

By contrast, this is a close-up of the pump output pipe, which is in profoundly, shocking, condition. This pipe is almost invisible and equally inaccessible, but would you want to drive a car where this was holding it off the ground? Obviously I'm going to replace it, but its a big clue about what makes ABC tick, or more importantly, fail. This pipe is unprotected. It does have a short rubber sheath to give physical protection against abrasion from the sub-frame and brackets, but there's no heat shield.

I've done a little research, and such heat shields are quite common and inexpensive. They're usually made out of woven fibreglass cloth - either woven into a tube, or sewed into one. They're called fire sleeve / sleeving, thermal insulation, aluminsed shield or braided heat sleeving or similar. Sometimes they're aluminised on the outside, like these, or coated with a robust silicone. All are good for high temperatures.

Its occurred to me recently that its the high pressure / high temperature hoses around the engine that fail most often.

My first thoughts were that all hoses had to be inspected every year, and replaced every five years (rather than simply when they failed).

My focus has turned to the vulnerable hoses close to the engine, that run at high pressure all the time. No need to be so paranoid about the cool or low-pressure hoses.

But given the good condition of those regulator output hoses above, I now think that we simply need to protect all the vulnerable hoses with suitable fire sleeves. I'm going to fit tubular sleeves over all my new pipes, but they can still be wrapped around existing pipes using suitable fastenings. I very much like simple, cheap, robust, solutions to difficult problems, and I think I've just found another one. This is what heat sleeves / fire sleeving normally looks like:




Nick
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Old 12-27-2015, 04:41 PM
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Compression fittings vs alternatives

https://mbworld.org/forums/s-class-w...ml#post6106551

I just replaced all the ABC hoses in my engine compartment, as I happened to have easy access (even to the ABC pump) and I have another lesson learned to pass on.

I used two different hydraulics shops, and I handed over my hoses to one of them to repair. They cut the hose out, made a new section with compression fittings, and fitted them. Unfortunately, they didn't clean out the sawing debris, which was left inside for me to remove. Also, they tightened the fitting, so the ferrule gripped onto the old pipe. Once you do that, it's there to stay.


Using a compression fitting has several advantages:
  1. No need for any special tools.
  2. Its easy to replace the replacement pipe when that fails.
  3. The hose can rotate about the pipe.
  4. The compression fitting can move up and down the bare pipe to some extent.
If the shop fits the new hose to the pipe, you lose that last advantage. Therefore Id recommend just buying the hose and fitting it yourself. You have the opportunity to get the length and angle of the new hose section just right, which is quite important. You don't want any hydraulic hoses to be installed under tension or twist.

I also recommend that you don't tighten the ferrule yourself until the last possible minute, when the installation is almost complete, then you can tweak the length until its just right. You can also make sure its clean inside.

To get the length of the hose right, just add 30mm to length of the section you're going to cut out. Compression fittings generally need 15mm at each end. Make sure you know where your pipe cutter or hacksaw is going to go, or simply cut the section out and measure that. Just a few cautions though:
  1. Before cutting anABC metal pipe, remove the paint by scraping and abrade it so its clean FIRST.
  2. When you cut the pipe, make sure you leave the inside of the pipe free of swarf.
  3. Be very careful to get the length of the new flexible hose right - you must never run flexible hoses in twist or in tension.
  4. Its a difficult temptation, but never tighten the compression joints until everything else is fitted just right.
Nick

Last edited by Welwynnick; 12-27-2015 at 04:51 PM.
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Old 12-27-2015, 04:43 PM
  #40  
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https://mbworld.org/forums/s-class-w...ml#post6542740

Replacing the King Pin Ball Joints

Hi Howard et al,

Long time no write. I've been so busing trying to keep our daily drivers on the road that I've had no time for my V12TT, which has been my dependable daily driver this year. How ironic.

My front king pin ball joints have needed replacement for some time, clonking and bonking over bumps like worn sway bar bushes. They're easy to confirm by using a screwdriver to lever the ball joint threads down, against the suspension upright. Mine had about 1/16 play on both sides.

The thing with the king pin joints is that they're pressed into the upright. Friction holds them in, so they're hard to push out. You need a special ball joint press, I bought one of these:



They used to cost hundreds, but someone must have started making them in China, and I got mine for 38 GBP. The press cups are specially design to fit inside and outside the joint on top and bottom. I don't think you could use generic press for this job.

Cheap or not, its a heavy tool, but I was still worried about my economy maintenance programme coming unstuck when faced with 167k mile joints. The press thread seemed like a rather loose fit, and I approached the job with apprehension last weekend. Sorry, I didn't take any pictures, but I wanted to talk about the approach. There are plenty of specifics and pictures on the internet; this is the best place:

http://mercedes-w220-ball-joint-diy.blogspot.co.uk/

I'm told you can press the joint out in situ, but that seems ambitious, and I removed the suspension upright on both sides. You need to use a lot of force - lots of big tools and big levers, and doing it in place didn't feel right. In particular, you need to fit the press in-line with the ball joint axis so you don't push it skew, and the brake rotor seems to get in the way of doing that.

I understand why dealers use a hydraulic press - this is hard work, but its quite feasible for an experienced DIY-er. It's not a job for a novice, but if you've replaced a ball joint or suspension arm before, then you won't be out of your depth. At the very least, you need to separate the lower suspension arm from the upright before you can remove the ball joint. You'll also need a lever arm ball joint splitter, as a direct acting tool won't give you access. You don't HAVE to separate the diagonal brake reaction arm, though I did. Its always good to inspect each ball joint and squirt a little grease in when you have the opportunity.

The press and the ball joints themselves aren't expensive, and I don't see how garages get way with charging lots of money for this. It took about four hours per side, but I did make life difficult for myself by snapping one of the caliper mounting bolts. That was difficult and time-consuming to get out afterwards, so consider what you would do if something went wrong.

Anyway, I recommend this job if you're inclined, and the tool DOES work!

Cheers, Nick



Edit: I thought I'd add a quick summary of what I did:
  • Jack up the front end
  • Support securely on stands.
  • Remove the wheel
  • Remove pad wear sensor & cable
  • Remove ABS speed sensor & cable
  • Remove caliper, and tie to upper arm
  • Remove brake rotor
  • Support suspension upright with jack
  • Split all four ball joints & remove upright
  • Remove ball joint by pressing upwards (hard work)
  • Fit new ball joint by pressing down (hard work)
  • Refit by reversing the procedure
  • Use allen sockets to hold the ball joints still
The upper wishbone ball joint is tricky as there's no hex drive. What I did was support the upright with a jack, and use a dog-leg lever to pull the upper wishbone down, and get the ball joint taper to grip. I used a speed brace like this to go under, over and under the top wishbone, and pulled it down with a jack handle on the end. Worked a treat.

Last edited by Welwynnick; 12-27-2015 at 05:07 PM.
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Old 12-27-2015, 04:45 PM
  #41  
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https://mbworld.org/forums/cl55-amg-...ml#post5746060

For those that don't frequent the W220 forum, here's an illustrated description of my second ABC hose repair.

While I was upgrading the IC system, I had the front end apart, which allowed easy access to the ABC pipe between the front valve assy and the RHS front strut. I knew it had been seeping for a few months, and wanted to change the pipe before it failed (and we were about to go on holiday). This is what it looked like from underneath:

The ABC Suspension Thread-p7270435_zpsf87f2e16.jpg

I raised the car, drained the fluid and removed the pipe - a few minutes' work for the valve end, and a few HOUR'S work for the "quick release" connector. I got my usual hydraulics contractor to make a new 3/8" two-wire hose with 10mm compression fittings:

The ABC Suspension Thread-p7280438_zps47b2a0df.jpg

They did it while I waited, and it cost £41. I scraped the paint off and thoroughly cleaned the metal pipes, then cut them with a plumber's pipe cutter, and fitted the new hose to the clean ends:

The ABC Suspension Thread-p7280440_zps70a467cf.jpg

I ran some Pentosin CHF-11S through the pipe, and part-filled it before fitting. Access is awkward to fit the hose to the valve assy, so its easier when the headlight, the horn and the headlight washer are removed.

The ABC Suspension Thread-p7290468_zpsb4b32a14.jpg

Here's the hose in front of the sub-frame. I skipped the solid pipe section there and protected the hose with a section of heater hose (I had a lot lying around...) and that fitted the existing bracket quite neatly.

The ABC Suspension Thread-p7290470_zpsc7122a06.jpg

Getting all the jacks and stands from underneath the car is tricky when the suspension doesn't support itself, but eventually I started the engine and raised the suspension up and down several times, keeping the reservoir fully topped up. It didn't leak a drop. A couple of days later I finished putting the charge cooler together and took the family on holiday. All that happened was I got a slight leak from a headlight washer pipe (another "quick-fit" connector ......).

That's how I look after ABC. This was a similar job to fixing the damper hose, but much easier this time due to better access, and simply because I'd done it before. Apart from the seized quick release connection, it was quite straightforward.

Nick

Last edited by Welwynnick; 12-27-2015 at 05:07 PM.
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Old 12-27-2015, 04:54 PM
  #42  
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And Finally:

https://mbworld.org/forums/s55-amg-s...refully-3.html
strut masters makes a kit that will get rid of this issue all together.
Yes. But then the car will roll in corners.

Nick
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Old 12-27-2015, 05:06 PM
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OK, finished! Thanks for your patience. I'll review and edit the posts to keep them concise and in context.
Any future posts on ABC that are worth recording, I'll copy over here as well.
The vast majority of posts I found in searching didn't make it here, but if you think I've left anything out, please shout.
Hope this is useful, and I hope that all the discussion on ABC doesn't have to be spread across a dozen different forums.

Happy New Year,

Nick

Last edited by Welwynnick; 12-27-2015 at 05:14 PM.
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Old 12-27-2015, 10:42 PM
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Awesome job putting this all together. You have surely saved many of us a lot of hours searching the forum for info on fixing/maintaining our ABC systems.
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Old 12-28-2015, 03:22 PM
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Thank You!!!!!!
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Old 12-28-2015, 04:50 PM
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you people are like drug addics feeding a system that will fail get rid of the problem unless you like throwing money away if you do I've got a bridge for sale!!!!!
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Old 12-29-2015, 06:24 AM
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Hmmm, not quite the sort of response I was hoping for. You could argue that I've spent too much time trying to get ABC working reliably, and it would be difficult to defend that.

I've always believed that ABC should be maintained and repaired, rather than thrown away. However, the thrust of this thread is how to get ABC working without throwing buckets of cash at (Mercedes!) dealers. Based on how my 163,000 mile S600TT is running, and how much it cost, I think I've succeeded on both fronts.

So I'm going to turn this round and ask how much you spent on your coil-over replacements? However much that is, I've spent a small fraction of that, and I don't have a car that pitches and rolls every time I have fun behind the wheel.

Regards, Nick

Last edited by Welwynnick; 12-29-2015 at 10:18 AM.
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Old 12-29-2015, 10:49 AM
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Originally Posted by dgschroeder View Post
you people are like drug addics feeding a system that will fail get rid of the problem unless you like throwing money away if you do I've got a bridge for sale!!!!!
this is uncalled for!! this thread is very helpful and negative opinions don't help anyone.
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Old 12-29-2015, 01:56 PM
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total cost of my coil over installed was 1800 that included installation with a new power steering pump and by the way no pitching and rolling and no red light
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Old 12-30-2015, 10:13 AM
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There are some glaring gaps in my understanding of ABC, and I'd like this thread to help pool information. Using SDS to control and monitor ABC is useful for some of the qualitative measures of the system performance, like pump pressure. The system is regulated to 190 bar, but the way it varies might tell us how its performing.
  1. How long does it take the system to build up to operating pressure from start? I figure it takes several seconds, but I have no idea what a healthy time is.
  2. For those who have done the rodeo, how much pressure drop do you get?
Some people worry that any drop is bad, but I think rodeo isn't normal operation, and you shouldn't expect it maintain full pressure. The point is to exercise all the struts as far and as fast possible, which means depleting the nitrogen accumulators. Dropping 30% seems to be OK, but something's not right if you're down into double digits.
I figure that both measures will give an indication of the health of the pump, but remembering that even a new pump won't charge instantly, or keep up with a rodeo.

Thanks, Nick

Last edited by Welwynnick; 01-05-2016 at 03:17 PM.
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