Pump Clicking, every three seconds

There are all sorts of other problems that cause more rapid clicking, both mine have new accumulator spheres and both tick at 5-10 seconds, the green one appears to have a leaking distributer valve, but anything that allows the fluid to return to the reservoir to quickly will cause it. On high mileage vehicles it can be general hydraulic system wear.

Peter.N.

That's interesting. So as dynamics of the hydraulic system is always changing - either as planned or just down to use - the problem could come and go. I will wait and see what happens.

Before it rapid clicking started, the car had been on a number of very short trips (5 minutes) with 24 hr gaps in between. If there was a slight problem with the hydraulics, this might have exacerbated it, while a long trip with fluid moving around a bit more could have relieved it.

MAybe.

Either way, you now have it going every 15 seconds or so, much better than the 3 you were originally getting.

As with Peter, my 2.0i (which I changed the accumulator sphere of on Saturday), is still ticking a bit too frequently, maybe 15-20 seconds instead of 10. A marginal improvement, but at least I know the spheres been done and there wont be any issue with braking capacity etc.
I think the pump is just tired on that car, it is heading for 18 years old, though it only has 80 odd k on it mind you. Its dead slow to rise from cold in the mornings too, taking almost a minute before the pressure warning goes off, then it rises quickly. Could be a number of things, but I guess its better to rule out the easy (and cheap) fixes first, and I wouldn't want to be without a sound accumulator...

My 2.1TD psssssts frequentish, but only clicks every 40-50 seconds or so, more if I press the brake a bit. It rises in 10 or 15 seconds flat too. Its a '95, but it does have more mileage than the 2.0i, so perhaps the S2 pumps are just more efficient.

Either way, ruling out the sphere helps you narrow down other possible causes.

I don't want to depress you, but I fitted a brand new pump on mine - no difference! I have had them fail in the past when one or more piston stops pumping, but not this time, its quieter though.

Peter.N.

Agree, the pump's state shouldn't relate to the cycling time, but only to the time it takes the pump to inflate the accumulator to from the low to the high pressure as governed by the pressure regulator (Of course a good/weak pump shows more in the morning when the system is likely to be low or 0 on pressure). A pump reinflates the accumulator from low to high in just an instant, as I've seen live with a pressure gauge. The cycling time is only an indication of how fast the pressure available from the accumulator is being consumed from the system's components (suspension cylinders, brakes, height correctors, hydractive valves). The prescribed pressure range for the accumulator on the XM -and most Citroens- is 145 (low) to 170 (high) bars. If the pump enters every 15secs, it means your system has consumed a volume of LHM that corresponds to the difference between 170 and 145 bars in the accumulator sphere of 400cc with a static pressure (when new) of 62 bar. This in reality amounts to a few cc. In an XM with the old pump (not 6+2), all the pump's effort goes to the FDV and is diverted between steering and pressure regulator (which then feeds the rest of the system). I'm not sure of the 6+2 arrangement, but the following will be valid if it also has an FDV: the first things to check after changing an accumulator to no avail, are:

0/ return pipes on LHM tank (any notable leaking from a component that shouldn't leak?> suspension cylinders, brake valve, and height correctors are not suppose to leak drops, if only to be "wetted" with LHM; hydractive valve(s) must not leak at all; don't know about steering)

1/ FDV (Does it leak? >refurbish with Citroen kit, few £)

2/ pressure regulator (Is it loosing more than 10 bars from low pressure point in 3 mins after switching engine off? >throw away. Does it regulate to the 145-170 range? >adjust pressures with shims)

Most people could carry on this tests easily but the problem is to build a pressure gauge (to read pres.reg. and re-tune FDV after refurb). C'mmon, someone in the group must have a connection to plumbing/heating ??!!! I'm sure the appropriate adaptors exist as I've seen photos on the web with nice DIY gauges for Cits!


regards
George

With new spheres, lots of Hydraflush and filters cleaned six times in 6 months I've recently found that my pressure reg clicks every 305 seconds (yep, I'm that sad to have timed it because I thought it wasn't clicking at all!)

Loads of fine black sooty particles have come out of the system during this time and now the filters have remained squeaky clean for 3 months.

So over 5 mins to bleed away to the cut-in pressure....that seems like a very clean & healthy Hyd system to me (115K miles).

Just gotta sort my front bushes now

This post has been edited by wirdy on May 30, 2007 08:10 pm

I reckon you've got an extra large accumulator sphere !

Peter.N.

So presumably Wirdy your suspension is nice?

Any advances from anyone on 305 seconds or does Wirdy have the record?

Yep, it's sweet.

The only niggle I've still got is a rattle from the front end over cobbles which I think is the wishbone bushes or the ARB bushes- have the wishbones bushes to fit, just waiting for some new pivot bolts to come from France. Even Peugeot didn't have any in the country (as they're the same as Pug 605 items).

Do I have the biggest (green) balls then?

...he's my hero !!!

George

...but has my hero bled the brakes after changing spheres??? In mine I got 2mins+ after changing all spheres on same day but next day after brake bleeding it was back to usual 30secs...

My advice: if u have not bled brakes, leave it as it is, u might have a bad surprise!

George

I've pulled 2 litres through all the brake lines

My alfa alloys mean I don't have to jack the car up or remove the wheels to do this. Easy.

This post has been edited by wirdy on June 01, 2007 12:55 am

That's very interesting folks, cheers for the suggestions on other possible causes.

I really must get round to diagnosing some of the other ones at some point (the 12th of never if this week is anything to go by!)

I still haven't fixed the alternator or windows on the green one... will need to book the test soon too, its up in august and the damn waiting list is like 10 weeks still......

Oh well, one day soon I'll have two perfect XMs

It'll never happen.....there's always that little something......