haydenb121

Hi, I have a 2003 cl500, I've got a whine around the pump area which increases with rpm, I assume its the pulsation damper, however I think I have 4 of the balloon shaped accumulators, but is there also a cylindrical brass sort of coloured thing below the pump? What is that please?

Also, I have another issue. After driving then stopping the red abc drive carefully came on, so plugged in my icarsoft v2.0 and it said system pressure low, so cleared it and was fine, flushed the fluid over the weekend and everything worked fine this morning levels all good and again after a few hours, but when starting warm the red abc warning came straight up, and the reservoir was completely full, so I thought ah accumulator, but then drove home with scanner plugged in resetting the code, and monitoring the abc pressure, which was at 0bar sometimes 1. Then about a mile from home the pressure went up to 187bar and it worked again. All levels are back to normal when cold and warm but..... When I start the car the pressure slowly builds to around 20bar and the red warning comes up again, however if I rev the car after start up a bit the pressure builds much quicker and no warning lights and abc works completely normally..... Can't seem to think what it is.... Only bought it 2 weeks ago, I went in with my eyes open and know the costs etc, but can't think if the whine and slow building pressure are due to either the pulsation damper or pump.... Also it never drops and sits pretty level all of the time. If you have any advice it'd be much much. Thanks

slonar21

You should not drive with red ABC light on, you might damage the pump, and if that happens, small metal debris will damage the valve blocks.

From what you are saying it sounds like the pump is starving for fluid, maybe there is a air pocket or more likely the pump needs to be replaced.

Get your car to a Mercedes specialist, I would get it towed, i would not even take the chance with the consequences of grenading the pump

haydenb121

Hi, I don't think it's fluid starvation, well now anyway. It's worked perfectly for a few days now, although sometimes I have to rev a little bit when starting to help build pressure to where the red light doesn't come on, but as soon as pressure is up to 180odd bar everything functions perfectly

slonar21

It sounds like the pump is giving up, that’s would be my guess

MrTracy

I agree i would look at the pump. I hope when you flushed the system you changed the filter.

Kebowers47

The symptoms describe a pump trying to pump oil with entrained air (bubbles.) Purging the air out of the system is sometimes complicated and takes several tries. Air in the fluid will cause the individual struts to behave erratically because the 'airy oil' will foam when the pressure is reduced. If there are bubbles visible in the reservoir, the pump is probably sucking in bubbly oil and it will whine and groan and may take several seconds to 'catch' and raise the pressure enough to lift the vehicle.
Leaving the reservoir 'open' overnight will help air to escape. Because the oil does not flow continuously, but only when and where the system decides to send it (like to a strut to extend it--raise that corner), getting the system free of air is not straightforward.

Once the reservoir is air-free, cycling the vehicle up and down will cause oil movement through the struts and more air to bubble out in the reservoir. Depending on how much air is in the system , it will take a few times of this fluid movements to clear all the air. I suggest say 2 cycles and then pause , repeat in 4 hours, etc. It takes some time for the dissolved air (bubbles) to float to the top and burst.

haydenb121

Thanks, yea it's all sorted, I replaced the pump, it was sucking in air, then a few days later it leaked from the Front pump housing. I replaced it and all working spot on again.

I also got myself an autel ds708 so I can now actuate the suspension etc for proper flushing

haydenb121

Oh, and the whine was the ac pulley, which took the same time for me to change as the abc pump!!! The old pulley fell apart and left me barely anything to hold onto and turn the compressor shaft, took 5 hours to undo the stupid thing! And to add to it I got the wrong size pulley, it was slightly larger in diameter so had to get a longer aux belt, but all sorted now!

Now I've just got a vibration on the motorway from the rear end so need to change flex discs and centre prop shaft bearing, or think it could be the rear subframe bushes as they look a bit worse for wear