2002 CL500 ABC Suspension Problems

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Oct 24, 2017
Hi Guys,

I bought a 2002 CL500 (knowingly) a while back with ABC issues. The car was pretty much right down on the deck when I bought it, but it was an otherwise well-cared for 2 owner car in excellent condition. It still started and ran A1 and it would drive fine. I've only driven it a short distance on the flat with as much mechanical sympathy as possible. It drives fine apart from the obvious bumpiness from the suspension. There is a constant ABC error message on the dash, but when driven it alternates between "Caution! Drive With Care" and "Stop! Car Too Low".

When I got the car, there was no fluid in the reservoir, but I filled it up and the level has not dropped since. It has made no difference to the suspension issue though.

The pump appears to be working in as much as it seems to rotate fine and there are no power steering issues, so I assume that points to the pump being ok or at least to look elsewhere first?

Without any obvious leaks (again, there are no guarantees as I've not really been driving the car other than short drives to try and fault find) and the pump appearing to be ok, where do I start?!

I know the valve blocks can be at fault. What can go wrong with these? I know you can buy a kit with new seals and O-Rings, but would this be likely to cure any problem or would they need a more thorough refurbishment/replacement? There are companies that can refurbish the ball joints on the shocks. Is that a likely candidate? Or could it be accumulators/pipework/something electrical?

I'm guessing it could be anything or a combination of things, but from the info I can give so far I could at least do with a few pointers as to where to look to first or the most likely causes of what looks like complete system failure before replacing parts one by one.

Thanks in advance!

This is how the car currently sits


With this ABC system it could be anything, but it sounds like the valve blocks are leaking. Power steering pump is conjoined part of two pumps, one is for the steering and other for the suspension. You can check the pressure it is giving out by connecting it to the STAR diagnostics. As for the shock absorbers , you can change the dust boots to give them longer life time , they are available on eBay and as for the bumpiness it is very likely that the top bushing is worn that can be cut out from a thick rubber. If you are interested we have a garage in Leamington Spa , we have some experience working with these cars.

Is the message in red or white on the dash?

With no fluid in the reservoir it’s almost a 100% guarantee that the pump is knackered.

The ball joints on the CL are on the bottom arms, not the bottom of the strut like the SL. The arms are around £150 each from Mercedes I think.
Bit of a change/progress since then. After filling the fluid up and it not doing anything I left the car for a few days. The level didn’t drop at all, but I fired the car up and the suspension raised to where it should be and all of the warning lights went off. I took it for a drive and the warning light came back on again (just the ABC Drive Carefully this time) and then a very noticeable leak developed. On driving though the car felt superb with the suspension raised, none of the bounciness from when it was on the floor. So there is a leak, but it only leaks when the suspension is moving or the car is running.

I’ve had diagnostics plugged in and it now says low system pressure (this comes back on immediately after clearing the fault codes) and after driving it, it comes up with faulty ride height sensors on all 4 corners (doubt that all 4 have gone, guess it’s just reading that as there is a problem with the pressure due to the leak). Next step is to get it up and see where the leak is coming from, but this feels like massive progress and really happy with how great the car felt when the suspension was up.
Strange, low pressure normally brings up a red warning...

I've had afew random errors on level sensors, a rodeo normally clears them but I wouldn't advise this with low pressure!

My guess is the pump but could be a burst line!

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