Mk1 Xantia hp pump

[aerodynamica]

The hp pump on old Katy is seemingly drawing air and pumping it into the system from cold. I think it's caused by the spindle bearings or the end float being worn and going all over the place. You can hear it for the first couple of miles in the morning rattling away.

I'm hoping to track down one of the elusive rare 2 pipe hp pumps and I might be able to get a nos item that's from a petrol model ( mine is a diesel ) that has a larger pulley. It's the only difference.

Question: has anyone ever removed this pulley? Does it press off/ on and do you know if it needs heated and pressed off. Just weighing up the possibility of the job

Any advice greatly welcomed

[RichardW]

Phone up Plaedies, and have a natter to Martin - he'll tell you all about it. IIRC removing the pulley is not possible.

[Stickyfinger]

I can confirm the quality of Plaedies rebuild work, superb company to send pumps to.

[aerodynamica]

Ok guys I'll call them thanks. G

[Old-Guy]

Are you sure it's the HP pump that's letting in air? Don't forget that it has to suck LHM up out of the reservoir, so the whole of the uptake system, from the bottom of the reservoir top moulding to the pump intake, is under partial vacuum; made worse when the LHM is cold and more viscous. And air has such a low viscosity that under the slightest negative pressure it will leak in at places that would require several hundred psi of positive oil pressure to show a leak (e.g. injector leak-off pipes).
The rattling when cold may well be effect of air bubbles removing the lubrication and damping of LHM.
The Green Lady suffered from air in the pump uptake (intermittent loss of PAS first thing in the morning) - fixed by making sure the filter was clean and trimming a few mm off the end of the rubber pipe onto the reservoir top moulding so that it could be pushed slightly further onto the plastic spigot to sealed better (pipe had stretched and gone a bit hard with age - must have been NFP or I'd have replaced it).

[aerodynamica]

Thats a good point, the suction pipe and all the LHM tank connections have all been off in the last 7 months because I cleaned the filter block and added an 'anti bubbling' set up for the return pipes so it's possible they've worked a bit loose since then. I did fit new jubilee clips to the suction and large return pipes (specifically sized so should have a good tight fit) but still, could be air getting sucked in.

The other reason I thought it might be the pump itself was that I had the same symptoms on my old Xantia 'Charlie Brown' and that certainly was worn pump bearings - you could visibly see the end float when it was running!

The mileage on Old Katy is genuine 80k so I'd like to think the pump wouldn't be worn yet and it would be nice to find it was just an air leak as that'll cost a lot less to fix!

I'll have a good look at the weekend and see what's what.

[Old-Guy]

Thats a good point, the suction pipe and all the LHM tank connections have all been off in the last 7 months because I cleaned the filter block and added an 'anti bubbling' set up for the return pipes so it's possible they've worked a bit loose since then. I did fit new jubilee clips to the suction and large return pipes (specifically sized so should have a good tight fit) but still, could be air getting sucked in.

The other reason I thought it might be the pump itself was that I had the same symptoms on my old Xantia 'Charlie Brown' and that certainly was worn pump bearings - you could visibly see the end float when it was running!

The mileage on Old Katy is genuine 80k so I'd like to think the pump wouldn't be worn yet and it would be nice to find it was just an air leak as that'll cost a lot less to fix!

I'll have a good look at the weekend and see what's what.

The Green Lady is only 3 years younger, but with 131,000 on the clock. The HP pump has never been touched, and is fine apart from a slight weep from the shaft seal - hence my comments.

The problem I found with the suction pipe is that it gets hard and slightly stretched over the 'swage' of the plastic stub and I couldn't get a good seal. Trimming the end slightly enabled me to push it tighter onto the 'swage' and hold it in place with the original size and type of hose clip. No troubles with it for the last several years despite being disturbed in August 2015 to clean filter and tank - just a matter of remembering that it needs to be refitted with attention to best possible seal.

[aerodynamica]

Re. trimming the pipe end: Citroen were not very generous with the pipe length! It is routed so close its whole length that trimming can make a bit of a stretch to refit. Note to self: don't trim too much!!

[Mandrake]

I'm hoping to track down one of the elusive rare 2 pipe hp pumps and I might be able to get a nos item that's from a petrol model ( mine is a diesel ) that has a larger pulley. It's the only difference.

Are you sure ? There are a number of variations of the pump which have different entry angles for the low pressure feed hose and the high pressure output(s). Although you might be able to work around the low pressure hose inlet being at the wrong angle if the high pressure output is in the wrong place you're probably stuck.

Question: has anyone ever removed this pulley? Does it press off/ on and do you know if it needs heated and pressed off. Just weighing up the possibility of the job

As Richard suggests, the pulley is non-removable, therefore the shaft seal can't be replaced. There is another seal that can be replaced though - there is a large o-ring under the triangular flange that you can access when the triangular piece (along with the pulley and shaft, which is permanently attached to it) is removed. It's not available as a spare from Citroen (it's not even listed) however I have successfully replaced it with a sphere neck seal on my first Xantia.

Another thing to check is whether the inlet spigot is tight in the housing - they can actually start to come adrift and admit air in the gap between the spigot and the body of the pump - I put some high temperature glue around the spigot on my first Xantia as a preventative measure just in case it ever leaked there.

[aerodynamica]

Quite right Simon. It's an assumption that the rest of the HP pump is the same save for the pulley. Anyway, it was only a thought for a solution.
This afternoon I bled the rear brakes again (air trapped in the LH rear brake only) and they're back to normal service once more, I took the opportunity while I was at the garage to remove all 6 suspension spheres in turn to check each for pressure drop and for any visible leaking. All 6 checked out at the right pressure (they're all each <1 year old) the only one that seems lower on pressure was the front Hydractive sphere that read at 70bar instead of the 75 it should be (400cc) but I think I recall that it was 70 b when I checked it out of the box last year. Anyway. I 'bled' the rear spheres upon refitting. And also the front corner spheres. The car rode very finely on the way back home. Anyway, I checked The HP pump pick up at the LHM tank and found the fitting to be tight. I checked the HP pump retun to the tank while it was running with the 12mm bleed open and no amount of tugging, twisting wriggling of the pipe connection would produce bubbles in the pump's return at the tank so I'm fairly sure the HP pump fitting is good at the tank. I've not looked at all at the HP pump end of the fitting though so that will be next to address.

[aerodynamica]

I had a look at this a few days ago before going on a work trip and with the car started from cold with the 12mm bleed screw loosened there are no bubbles fed back to the LHM tank. It ran for several minutes like that. As soon as the bleed screw on the preussure regulator is nipped up and the accumulator charges, the return of LHM to the tank at regulator cut out is a foam of bubbles. It remains cut out and the bubbling continuses. Surely this is evidence that the HP pump is drawing air under load? You can hear it too in this state. With the bleed losened the HP pump is totally silent as you'd expect but surely it would still draw air in the unloaded state too?

[Mandrake]

A couple of thoughts:

Accumulator sphere leaking nitrogen, but only when the diaphragm is compressed ?

Also that early model has a FDV doesn't it ? With the bleed screw open does the power steering still carry most of the return flow or does it only carry most of the return flow with the bleed screw closed and the accumulator up to pressure ? In that case perhaps the low pressure return from the steering rack is drawing in air ?

[aerodynamica]

Hi Simon, that's right it had the FDV. If I recall when the bleed is open virtually all the flow goes back to the tank via the bleed and a tiny amount goes through the pinion valve via the FDV. A strange phenomenon is that with the engine running and the big red stop light on, turning the steering wheel actually allows a bit of pressure to build up enough to put out the light of a few seconds as the flow is part restricted by the pinion valve.

I suppose you're right it could be another source but with these return pipe sort of air leaks I'd expect LHM to leak out in service and there are no leaks at all apart from around the pump itself

As for the accumulator leaking nitrogen, it is just such high pressure that you'd always be getting bubbles. The bleed screw being open would still catch the bubbles and let them through (possible mure so as they'd be technically 'vented' in that state. The other thing is that it does it only under the initial HP pump load and also only for the forst bit of time whereafter it seems to clear or 'prime' or other. I still feel it's the pump itself.

[xantia_v6]

Maybe when the pump is loaded the shaft bounces around more, exceeding the flexibility of the shaft seal?

[xantos]

Damn bubbles! When will we get to the bottom of it!