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I could probably write a 10000 character post describing what I´ve done so far - but let´s get straight to my current situation. I´ven been reading A LOT about the ABC system. I like cars, love driving but really enjoy overhauling so thats not a problem for me that I´ve got a ABC problem now.
Sunday evening = 0-2bar pressure (according to STAR).. Monday evening a quick "fiddle" with the suction valve at the pump (gave it 40-50 +5v "hits" and the sound from it went from a bit "sluggish" to more "magnetic valve" sound.. hard to explain but you might get what i mean).. Then started the engine getting 185 bar in STAR.. But down to 120-130 while raising the car... During rodeo below 100 (95 at the lowest) but mostly around 120-130.. Probably bad accumulators and maby a weak pump..
Tuesday evening - checked under the car.. Oil.. Damn.. But not very much. Removed panels and it seems as it might be coming from the pump. Sour but maby it´s possible to rebuild with new o-rings etc.. Otherwise a new pump.
Main question though.. After having checked the front valve block as well as the pressure regulating block with the pulsation dampener i realize that the last part of the line coming from the pump to the "first block" is sweating. Still haven´t done anything about it but i defenitly needs changing.. But - the pressure line goes from the pump, along the front of the engine and then along the right side (passenger) of the engine, appears (what i can see and figure out from drawings etc) to run over the gearbox and out into the wheel arch (correct word? - sorry - my technical english language skills needs improvement)...
Looks pretty hard to get it out - and even worse to get it back into place.
So - main question so far (this thread may turn into my DIY ABC rebuild story) - what if I was to replace the first part of the ABC system with a hose - let´s say runnig under the pump, up to approx. where the left headlamp is, down somewhere there, up just by the front valve-block with accumulator for front axle, up "above" the inner plastics above front wheel (there are holes to attach clamps) and back to the pressure sensor/pulsation damperer block.
About the same lenght, easier to install, easier to inspect.. A hose all the way instead of pipe-hose-pipe-hose as the original setup seems to be. No need for heat-insulation as it is a fairly protected area compare to runnig along the engine.
Long post for a small question - but has anyone tried this? I recon it could work..
Next step anyway is to remove pump etc and start to check status of several components..
Brgds,
Pelle
Last edited by perren75; Jun 16, 2016 at 01:05 PM.
There are a lot of ABC design features that seem pointless, but which are actually the result of a lot of development - finding out the hard way.
Hydraulic fluid is pretty incompressible, so if the system didn't have all those nitrogen accumulators and flexible hoses, it would suffer form a lot of noise and vibration, caused by the pump and the valves, and transmitted by the oil itself. There are several pipes that run backwards and forwards for apparently no reason, except to provide damping and absorption for the pressure waves that would otherwise propagate around the system. The most common example is the noise created by a failed damper on the pressure regulator.
You could probably try to re-route the ABC hoses, but it almost certainly won't work as well as the MB design, and you would also have great difficulty replicating the MB specific fittings. Hydraulic shops generally won't be able to make them. I tried three years ago. See the thread below for more explanation:
The best thing you can do to ABC is change the oil and filter every three years, and cover all the flexible hoses in the engine compartment with heat sleeving.
Nick
Last edited by Welwynnick; Jun 16, 2016 at 03:28 PM.
I did a flush shortly after bying the car last year... At the moment there are no other problems with the ABC system apart from the fact that i have a leak - probably in the pump (a bit hard to see) and of course the fact of low pressure and the probability of the suction valve might be on the end of it´s lifetime (those are actually available as a spare part for ~300 Euro from e company in Germany - found it on ebay.de when searching for the ABC oil filter and oil).
But - my main concern are the hoses that are heat-insulated around the engine. Impossible to do a good inspection without removal i think.. And i´ve not found any good info on how to remove the.
The last part of the line from the pump to the dampener is sweating. This part could easily be removed as the line i splitted with a connection easy to access.. The hose looks like this;
Sweating ABC pressure hose
And that´s definitly something that needs replacing.. I have a feeling that the other hose-parts of the pressure line looks the same under the heat-insulation. It´s not a problem now - but will be once any of those hoses burst. The one in the pic is dripping.. Not much, but any leak is to much imho.
The banjo-couplings could probably be re-used if i cut the pipe and go to a hydraulic shop and have them either attach a hose directly to pipe - or - a coupling for hydraulics.. But i have a feeling that it also might be possible to get the correct banjo new.
So either I have to try to remove the pressure line going around the engine to have it rebuilt with new hoses - or reroute - maby inside the fender above the plastics above the wheel.. There seems to be enough space. But if removing and reinstallning original line is possible - that´s of course a better way to go.. Has anyone done this on a SL?
I've read your thread and seen those pictures before Welwynick.. The info you've written is very useful!
Good news - the pressure line goes below the tranny and I've just removed several clamps holding it (5 i think). There are three left as far as I can see right now. One seems rather easy (last one before the compression coupling one the left side where it leaves the engine room), one holding the pipe section in front of engine (seems to be attached to engine - might be hard to access) and then a hose clamp next to it that I still haven't figured out how to loosen.. Well - Friday evening here in Sweden - new day tomorrow. No sailing this weekend in favour of the merc
The pump is out.. I've disassembled it and it looks good inside although the seals are worn.. Have checked a few sellers but shipping cost is very high compared to the price of the "kits" so tomorrow I'll go to a local firm selling o-rings and shaft seals and check if they can provide... It's expensive to have these rather cheap things shipped to Sweden - about as much as the price of the products in shipping
The pressure line was a ***** to get out.. I had to cut the hose between the first pipe section to the second - just in front of the engine below the crankshaft. There is space space enough to connect a compression coupling when reinstalling the line. After doing that and raising the engine a bit I got the (now in two parts) line out. Removed the insulation and after a quick inspection I thought it looked rather good but then on the other hand - might as well replace it all when I have A good possibility to do it. Will bring it to some hydraulic firm doing hoses and pipes tomorrow.
So current status is still on jack stands but it's starting to feel a little better. Have had time for some sailing also and weather hasn't been "roof down" the last couple of weeks so it's rather ok with the jack stands
I will probably go with more hose and less pipe when rebuilding the pressure line.
If I only had a bigger garage and a good lift.. Hate working lying on the floor... Biggest problem now - summer vacation is coming... Would have been great to reassemble everything before that but time goes fast and soon we're probably out sailing for 3-4 weeks... Life's hard
Bought a rebuilt pump from Germany, got the pressure line fixed in a hydraulic shop in Gothenburg (Hydroscand) and replaced most of the piping with high pressure hose that according to the tech there is far much better quality than the original hose.. Also bought heat resistant protection for the hole hose.. Installed new pulsation dampener and front accumulator. Have the two for rear block also but want to get the proper tools to disconnect the hoses before replacing..
I ended up rerouting the pressure line...
Pressure line in front of engine..<br/>
Picture isn't very good but the original pipe was cut just before the mounting plate in front of engine - the the hose is protected by an orange sleeve and does a 180 turn towards driver side.. Then under front valve block up over left front wheel down to the pulsation damoewner. Did actually plan to run the "original route" but since it was a bit to long this became the solution.. This way it's no where near the exhaust saving it from excessive heat...
Put everything into place yesterday, topped up fluids and ha a testrun in the garage for 20min to check for leaks. All good and I also did a short rodeo - what a difference compared to the old pump. Pressure above 155 bar all the time, car moving much more firmly and quicker. Today I did a 50min / 40km test drive and all seems to work great. The chassi seems firmer and more responsive than before..
The throttle valve in the pump got a good cleaning - it was dirty and opens a lot better now than before. That might be one of the problems but when I disassembled pump I noticed that one of the bolts holding the spring loaded Pistons probably had unscrewed itself 1-2 turns... That might also have contributed to pressure loss - and if it had come out more there would have been bigger problem...
Feels great to have the car running again as summer is not over just yet
Do you know what spec hose you used? Was it 3/8" two-wire SAE 100R2 AT hose?
Cheers, Nick
Thanks!
Not sure about the SAE but it´s a 3/8", two wire with MPa 38,5 = 385bar.. -50 to +100ºC... The specs say that it should last 4 x working pressure.. Here´s a link to the hose - unfortunately in swedish..
It bends rather well (radius 70mm) so it´s easy to work with when "routing" inside the enginebay..
Acutally found a PDF in english with the following info;
The heatsleeve was almost as expensive as the hose with fittings and the work with it - but it feels safer with it protecting the whole hose even if it´s not that exposed to heat with the new "routing".
But i think they were very fair and gave me a real good discount.. It totaled ~ $180.. (1541 SEK)
Changing the rear accumulators is definitely doable without disconnecting all hoses and totally removing the valve block.. I can be done with just removing the clamp holding the lines and pulling valve block back.. It's a bit tricky as its not very spacious but it works.. Read a few posts here and there saying it can't be done - but I can - just did it....
Oil level now is exactly as it should - so either the rear accumulator or the return accumulator was bad. Probably the return.. Did the "screwdriver test" on both big accumulators and they seemed firm but before the change I got 7-8mm lower level with engine off than now.. Engine rpm drop when going from low to high chassi level is now gone and it moves much firmer and faster than before..
Thinking of driving it to work tomorrow... Not sure if I dare yet but maby it's the best way to start trusting the car again after the chassi fail..
Out of the garage after abc trouble...
Only done about 1500km so far this year... Cost per km is high - would feel good to do twice that at least before winter is here...
Changing the rear accumulators is definitely doable without disconnecting all hoses and totally removing the valve block.. I can be done with just removing the clamp holding the lines and pulling valve block back.. It's a bit tricky as its not very spacious but it works.. Read a few posts here and there saying it can't be done - but I can - just did it....
Oil level now is exactly as it should - so either the rear accumulator or the return accumulator was bad. Probably the return.. Did the "screwdriver test" on both big accumulators and they seemed firm but before the change I got 7-8mm lower level with engine off than now.. Engine rpm drop when going from low to high chassi level is now gone and it moves much firmer and faster than before..
Thinking of driving it to work tomorrow... Not sure if I dare yet but maby it's the best way to start trusting the car again after the chassi fail..
Out of the garage after abc trouble...
Only done about 1500km so far this year... Cost per km is high - would feel good to do twice that at least before winter is here...
Brgds,
Pelle
Nice job)
West coats Sweden ..... fare from Strömstad? if not then lets meet ..... several SL55AMG's around here
About 125km south of Strömstad... There are at least three near where I live but we newer seem to be on the road at the same time I might just have to go a bit north
Did a 30km testrun yesterday and drove it to work today - what a difference.... Feels like a new car (the chassi at least).. Much firmer, smoother and better ride than before.. The replacement of rear and return acc really did a great difference..
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
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I might just have to go a bit north 
