I posted this in the NON-AMG W220 forum but I don't think too many users there are dealing with ABC and are not so interested, I think this is a better place for it since I know that ALL OF YOU have ABC and I always see threads about fluids, hoses, pumps.. etc... I figured this will give you a nice visual into the complexity of this system...

I was pulling out of a parking lot, driving about 5MPH, 1st gear around 1000RPM when I heard a loud "bang" under the hood and I temporary lost power steering, which returned several seconds later. ABC Visit Workshop came up immediately promptly followed by a red ABC Drive Carefully! and right about then I smelled the mineral oil which must have hit all the hot components under the hood. Lucky in my case I was about 1/5 of a mile from my house so I slowly made it back home... the car was leveled fine but within minutes I had a pool of mineral oil (ABC fluid aka CHF 15S) on my garage floor:



I went back the next morning to see if any components fell out, or broke loose, or if I hit something on the ground, but all I saw were trails of ABC fluid stretching from the parking lot all the way to my garage door (and it looks like the stuff was spraying out with some pressure!)...





I'm was not sure what had happened.. I had several ideas... one of the fittings broke on the pump, the pump case was damaged, one of the hydraulic lines could have split open, valve body might have cracked, pulsation damper, pressure sensor, etc... it could have been anything, impossible to see from the top of the car.

One thing for certain, I knew that I would need a new pump because driving the car home with little or no fluid would have damaged the pump rapidly as it's a radial piston pump and requires constant lubrication with no ingestion of air.

 

Don't try this at home. You will need a place with a lift, full tool box and Mercedes SDS.

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The ABC tandem pump has a high-pressure side that uses a radial piston pump for the ABC side, which runs at 3000 psi. There is also a low-pressure side that side that is used for the power steering.

The ABC side has two lines coming out of the pump, one line goes to the pulsation damper which then distributes the fluid to the rest of the system and the other line ends in a "dead end" and I think it's designed to provide pressure relief. The lines go from metal to rubber to metal again, looks like my line let go at the connection from rubber to metal, causing fluid to leak out and everything else goes down hill from there.

The ripped line:





The space in the nose of the car is very tight, there are a lot of lines, hoses, wires, etc...





Since all of the fluid was drained from the system, the ABC pump ran dry and ingested air, causing damage to the pump it self. The pump needs to be replaced along with the broken line. Because the M275 engine is big, and the engine bay room is tight, most of the components on the front driver's side needed to be removed, starting with the airbox, ABC fluid tanks, A/C line, Radiator Fan, Coolant Lines, Transmission fluid lines, etc..



Once removed, access to the pump is still very limited:



In order to access the banjo bolt that connects the ABC high pressure lines to the pump, the driver's side engine mount needs to be disconnected from the subframe and the motor has to be raised on the driver's side with a jack:





Once the engine is raised, the high pressure lines are disconnected and the pump can be unbolted from the engine. This is the empty space for the pump once removed:



Here is the new pump after installation:



Once the pump is in, the new lines are installed and the system needs to be filled and bled. This requires Pentosin CHF 11S mineral oil, which is not cheap at about $40/liter...

 

Here are some pictures of the old lines and the new ones. Notice the differences in design and the use of heat shrink to further deter the hoses from corrosion...

Old lines and pump:







Here are the new lines and the new pump:

 

Few things to keep in mind... everything must be free from grease, dirt, dust, etc... especially all of the hydraulic fittings. Engine bay was washed down completely and the rest of the spilled ABC fluid has to be cleaned up by hand.

 

I am speechless.....You are the man bro. To do all this requires a lot of patience on ones behalf. Way to post this up and have your ride back in great status.

Thanks for posting!

 

Good work, thanks for the time to took to post your adventure.

 

Are the new lines less prone to breaking?
If they arent could a guy just go get some made at the local hydraulic fitting shop that are superior?
I keep reading about these lines and cant understand why this isnt a recall?

 

Well, can't say that they are less prone to breaking, but they would be slightly more resistant to corrosion dude to external elements because they are wrapped in heat shrink material that overlaps the hose and the metal tube.

After seeing what happened, I think you nailed it. There should be no reason that a hydraulic shop can't duplicate those hoses and create something that is much superior... I'm going to look into that because I'd hate to do this again.

There is a recall... on one specific hose, which runs across the underside of the transmission by the catalytic converters, the only reason that it's a recall is because it can catch on fire should the hose rupture by the cats.

 

Please keep us updated. This could be an absolutely essential mod for these vehicles.

 

How many miles were on the car when the line blew, had the line started to show saturation by the crimp? Just wondering if we could get proactive and may save the ABC pump with a real good inspection of the lines?

 

I have already made contact with a company and they say if I can bring them down a sample they can make them.
Does anyone know what PSI the ABC system runs at?
If I know that then I can get the shop to make the new ones with a higher pressure holding capacity and voila.
I geuss this would still need to be done with a star diag machine? Can I change the lines then take it to the dealer for the rodeo?
I just hate letting the dealer do anything to my car.

 

Well if you actually READ my thread, you'll see where it says that the ABC pump runs at around 3000 psi or 200 bar.

 

Haha, I did read it the first time and it must have slipped my mind since. Man im getting old.

 

you know, after looking at it a bit... that is a fine pic

 

Thanks for the info!

 

Very interesting information. A couple of questions

- Is the bleeding procedure difficult?
- What procedures do you need MB SDS for?

 

you have a pretty nice wheels...Nice pics too man...

 

Thanks... that was one of the few pictures I took with my D200 that day... I was using a 12-24mm lens at 12mm to get that wide angle.

 

Well before you bleed the system, you need to prime the pump. You do this by pressuring the ABC fluid tank with air to around 4 bar. Once it's pressurized you have to carry out a step-by-step procedure specified in Mercedes WIS. You also have to prime and bleed the power steering system, since it's run by the same pump. It's a bit lengthy but it requires the use of SDS to perform actuations such as Pressure Value, Pitch, Rodeo, etc...

Like I said it's not really a DIY in your garage kinda deal... bring it to a me, a Mercedes mechanic experienced with ABC or the dealership.. but it will be a lot of money at the dealer as all this stuff takes a lot of time and cleanliness.

 

Thanks! Here are some pictures of the rideeee...

 

Nice going with the repairs You saved yourself a bundle by DIY.

 

You do take some serious pictures bro. Nice DIY

 

I got my ABC pump replaced to day, it's out of warranty but MB contributed.
The bill was £600. I now feel the ride is firmer and without doubt there is more
weight on the steering which is great.

 

I am in the process of buying a 2003 CL55 and the pump was changed last year, thank goodness. Great information many thanks for the time and effort.

 

How did you get away with paying just £600? The pump alone cost me $1,377.00 and that's my cost, regular walk-in at the dealership is around $1,650.00 for the pump. And that's without the hydraulic lines which are another $400.00 and the fluid at $40.00/liter...