R230 ABC - odd problem. Help!

[Oldcodger]

Hi all,

At my wits end with this odd problem I'm having on my 03/04 SL500 ABC system. I've got 39K on the clock

Started with the dreaded red warning to Drive carefully etc etc.

System had been flushed and refilled about 18 months and few miles prior. First thing then check levels which were low on the AN dipstick so filled to level

Had a period then of the warning appearing/not appearing and pools of fluid appearing under the left front wing traced to the filter/filler area on the expansion tank

A friend with the right kit cleared the messages for me and rodeo'd it and then filled to correct level again.

After running for a while the car was left and the Red warning came back and fluid ejected from same place overnight.

The ABC will raise and lower happily so long as the level is kept at a point about half of the recommended on the AN dipstick. Put any more in and it spills its guts again once you switch off.

I did notice that the seal under the filter cap had been deformed when the flush was done and I tried to refit correctly but fluid certainly comes out of there rather than the filler /dipstick

It seems that I have a functioning system apart from this and nobody near me (in the North East) seems to be able to diagnose and fix

Any thoughts recommendations on this issue greatly appreciated.

Meanwhile I dont go out without a tin of fluid!

Thanks

 

[Richard Moakes]

It sounds like you have a weak (failing) ABC accumulator, it’s filling with fluid under pressure with the pump running and then pushing the fluid back to the reservoir when the pump stops, hence overflowing etc.

The challenge is identifying which accumulator, I think Xentry/ DAS can help with that?

 

[Malcolm Johnson]

I would concur with Richard re accumulator possibly as a start point. With the low mileage the system hasn't been functioned that much.
Rubber will be on its last legs due to age. Sadly at 20 years it is a lottery at what will go next. Be on good terms with your indie.

 

[Oldcodger]

Thx for replies

Wouldn't an accumulator fault lead to sagging? I dont have any movement at all in low or raised position...

 

[Richard Moakes]

Thx for replies

Wouldn't an accumulator fault lead to sagging? I dont have any movement at all in low or raised position...

Failed or failing accumulators don’t lead to sagging. The struts are valved off when the ignition is off. They are only active with engine on, pump running and provide a reservoir of pressure and damping of the hydraulic circuits.

 

[Oldcodger]

Ah Ok - perfect sense

Just need an Indie that is interested in tackling it then?

 

[Oldcodger]

I've been swotting up on the youtubes on changing accumulators and I may be tempted to give it a go myself

Problem 1 What are the correct part numbers? Do we have a part DB somewhere please?

Problem 2 Any supplier recommended in the UK? --Seem lots in the US/Canada

Problem 3 Am I mad for even thinking about DIY?

Cheers

 

[AMGeed]

Problem 1 What are the correct part numbers? Do we have a part DB somewhere please?

Here is a link to the Parts catalogue for your SL500

Mercedes FG 230.475 (65P) > Mercedes EPC Online > nemigaparts.com

Parts catalogs. Spare parts catalog Mercedes EPC Online. Mercedes. Car. Mercedes FG 230.475 (65P).

nemigaparts.com

 

[alexanderfoti]

As above, definitely the accumulators,

As they have failed, you need to flush the system fully after replacing all 3, you may as well do the pulsation damper at the same time.

Buy MB OEM , they are not much cheaper aftermarket and you want the quality behind you on these.

 

[Oldcodger]

Thx all. I know location of Accys but where is the pulsation damper located?

I've got a sympathetic Indy that agrees with the prognosis and is pricing the job up for me

 

[alexanderfoti]

Thx all. I know location of Accys but where is the pulsation damper located?

I've got a sympathetic Indy that agrees with the prognosis and is pricing the job up for me

Nsf front wheel arch, towards the rear, inside arch liner