XM hydraulic/brake pressure warning lights on!

robbocop33 · Post by **robbocop33** » 02 Dec 2005, 19:35

Just bought XM 2.1 td(1993)and on getting it home decided tocheck everything was alright undernath,discovered 4 union pipes going into the pressure regulator were slack!!Tightened them up,tried suspension up and down a few times and it was flying up and down.But,all the time when i started the car there was a constant ticking form the pressure regulator about every 2 seconds,this went away while moving steering.It would also click getting faster and faster while going up to its full suspension height at rest,then,turning the car on later Brake pressure loss and Hydraulic pressure loss came up on the dot matrix display and the 'stop' warning light stayed on,no steering,no brakes and no suspension at all?The ticking also stopped.There are absolutely no fluid leaks now whatsoever.There was a recon hydraulic pump fitted to the car two years ago but maybe there has been some strain on the pump with the last guy driving around all the time with the fluid leaks all the time?Anyone any ideas?thanks.

Mandrake · Post by **Mandrake** » 02 Dec 2005, 19:46

Sounds like you could have two problems,

A totally flat accumulator sphere would cause the regulator to cycle on and off very rapidly - 2 seconds is quite believable if the accumlator was punctured.

If it is you should get that replaced ASAP as a flat accumulator puts a lot of strain on the hydraulic pump as it has nothing soft to pump against and may damage itself long term.

Your other problem sounds like an air leak on the rubber inlet hose from the hydraulic tank to the pump - usually if the car will pump up and pressurize one time, and yet another time for no apparent reason it will sit there with the stop light on and not pressurize, its because there is an air leak that is big enough for the pump to lose its prime.

Note: depending on where the leak is, it probably won't cause any oil to leak out, so just because there are no oil leaks doesn't mean there are no air leaks.

So I'd check/replace that accumulator first, then start looking for a crack on the pump inlet hose and check the hose clamps for tightness as well.

Have a look at this recent thread about air leaks on the pump:

http://www.frenchcarforum.co.uk/forum/v ... sc&start=0

Oh, and it probably goes without saying, but since you mention there may have been leaks before, check the fluid level in the tank. (Although you won't be able to do this until you get it pressurizing again as the suspension has to be right up)

Regards,
Simon

citronut · Post by **citronut** » 02 Dec 2005, 19:51

replce the acumalater sphere then with susp lever/switch on highest setting,engine running open bleed valve thats the 12mm bolt head on the front of the regulater,only undo it about 3 quarters of a turn,let it sit there like that for 2 to 3 minuits then close the valve and see if susp/brakes/steering work corectly
regards malcolm

robbocop33 · Post by **robbocop33** » 02 Dec 2005, 21:07

There is also a receipt that came with the car saying that the accumulator sphere was replaced exactly one year ago,they must have taken it on a few forrest rallies:-)I'm taking it by your replies that Hydraulic pumps are quite hardy things and should be the last thing looked at.I just couldn't believe how quickly everything went dead.Fluid levels are ok.I'll order another accumulator sphere tommorrow,thanks for the quick replies!Appreciate it.

AndersDK · Post by **AndersDK** » 02 Dec 2005, 23:19

The complete "manifold" in the LHM fluid reservoir can be lifted up (wriggle it - jiggle it). Then you can see the attached filters which can (and must from time to time) be cleaned. They detach smartly by small clips. Clean in petrol and blow dry.
Blocked filters give exactly the same symptoms as airleaks on the pump's suction side.
Note that the pump is surprisingly weak on the suction side despite its 300+ bars (yes !) capability on the pressure side.

A '93 model pump is quite sturdy. Should easily last the liftetime of the car - 200K+ miles.