ABC Fluid Needed 20 ml of fluid, now “motor an”:fluid level is right but “motor aus”:level is about 12mm too high on dipstick?

[Submariner1]

I remember reading there is a ball like reservoir somewhere near the back, that can fail. from memory I think they said if the membrane fails or partially fails then the level difference is a tell tail sign.
am I right ? Or any ideas.
Other question :- should abc fluid be checked when its fully hot?
TBH it was freezing here and I only drove it for 4 miles ( not high speed). Maybe it was not fully warmed up as its seriously cold here today.

Any idea where this rear ball like reservoir is on a 2009 CL500 W216?

Note no fluid loss on the ground, front struts are clean.
and I had the pulsation damper replaced 2 years / 4,000 miles ago

 

[ajlsl600]

My read, if ur topping fluid, when car at opp temp and no visable leak anywhere, chances are diaphragm in accumulator or accumulators leakin and filling with abc oil

 

[drmw]

I cannot remember the detail, but there are two levels on the ABC "dipstick" - one for when the engine is off, the other when it is on.

 

[Richard Moakes]

You either have a leak, or an accumulator is failing, just had the same situation myself. Got all the parts/fluid, just need some decent weather to do the work.

 

[Flyinspanner]

@Submariner1 iirc there are 3 accumulator spheres on the ABC system.

 

[Teem50]

@Submariner1 iirc there are 3 accumulator spheres on the ABC system.

I'm in the process of reading into the ABC system as this SL500 I've just bought is doubtless going to go wrong in a while.

There are 2 accumulator spheres in the flow side, one for the front and one for the rear. There's an additional sphere in the return flow which I think is just to even out the pressure pulses, caused by the struts being activated, in the return line to the reservoir. There's also the pulsation damper which looks like another sphere but is there to even out the pressure pulses from the pump itself. On later versions of ABC that damper is actually on the tandem pump itself.

I've found loads of useful information in this blog post, including a really useful schematic diagram of the entire hydraulic system: http://mercedes-abc-drive-carefully.blogspot.com/2014/

Tim

 

[alexanderfoti]

Engine off must not be checked immediately after engine off, give it 15 minutes or so to check the upper level.

I cannot infer from your description where the level is.

Where is the level when the car is not been running for 15 minutes.

 

[Richard Moakes]

C216 has a front and rear accumulator along with a pulsation damper, which on the v8 is attached to the ABC pump. Front accumulator is at the NSF corner, attached to the valve/solenoid block. I believe the rear accumulator is above the exhaust silencer, but not had a chance to look with the bad weather etc.

C215/W220 has a third accumulator, not sure what where that is located.

 

[alexanderfoti]

C215/W220 has a third accumulator, not sure what where that is located.

On the rear valve block.