My Citroen XM 3.0 PR-Vestige

[White Exec]

Interesting details about bearing wear and lock-up.
Bearing wear could prevent the pump operating at higher speeds (bearing vibrational bind).

Wonder if using a 6+2 pump is a possibility, with the 2 being returned to reservoir.
Units seem to be relatively trouble-free.
Come with grooved pulley; only one other to change, if feasible.
Probably a dozen reasons why not.

[xmexclusive]

I think the larger the pulley the greater tension you can put on the bearing.
Citroen went over to SEEM belt tension checkers presumably to reduce instances of excessive belt tension.
I note that most of the posts for Vee belts on here recommend winding up as tight as you can get it.
That may not be the best option.
Perhaps in some cases perceived belt slip might actually be air ingress on the pump shaft bearing from a already over tightened belt.

John

[Dean]

Isnt output pressure on the 6x2 pump integral to the pump? in which case the 6 pot side would not produce enough pressure for the brakes and suspension, and the 2 pot side not enough flow for steering?

Interesting about wear and air ingress, the V6 pump is mounted rather high up in the engine bay so will have less head of pressure from the reservoir when stationary and may not be so willing to leak but air will be drawn in all the same, no air bubbles in the reservoir though, i looked last night.

I do not have a later pump, i do have a head full of fluff though, mine is 107mm overall diameter, thats why the longer belt was, um, too long.

Getting a later pump will reduce the drive gearing, pump speed and increase belt contact area and that may be enough to cure the problem on it's own.

Damn! new pump

D

[Dean]

Pleiades don't have any on the shelf but can do mine with a next day turnaround for £180 plus carriage.
Need to phone back tomorrow and speak to Phil though to see if they have a larger diameter pulley they can fit to it.

It's a lot of dosh considering im not really sure air is getting into it but it's a better proposition than a second hand unit. They supplied me with a recon unit for the 2.0 engine many years ago and it made a big difference to low speed steering feel so............................

D

[citroenxm]

Do you want me to seek out a larger pully pump dean next week or you wanting to sort it sooner..? I was at farm today and picked up a v6 pump but put it down again

[Dean]

If you have one Paul that would be good to have but I'm debating about a reconditioned one at the moment, i will need to speak to Phil tomorrow and see what he says and if they can rebuild mine with a larger pulley.

D

[Dean]

I think i have sort of solved the problem, after talking with Phil at Plaiedes today and looking into the idiots guide to V belts i have decided to switch to a solid style belt which although has a lower coefficient of friction it is infinitely better suited to applications where belt load changes suddenly, like with a switched hydraulic pump, i stumped up for a top notch belt and so far it is performing perfectly with hardly and tension, in fact, the slack side is flapping a little but without a hint of slipping.

image by Deanxm, on Flickr

So, lets see how we get on.

D

[White Exec]

Solid belt presumably provides greater frictional surface area, but is less flexible.
If not having to negotiate very small pulleys (like an alternator), it should run well enough.

[Dean]

We shall see, i'm away for the weekend so the car is put away but i may get some use out of it next week, i also have a spare solid belt as i bought two.

D

[MTXM]

That does sound positive Dean and hopefully you have solved the belt issue now! Regards, Matthew T.