Leaking pump likelyhood ?

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Mandrake
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Leaking pump likelyhood ?

Post by Mandrake »

Hi All,

In another thread I mentioned that I was replacing the hose on my Xantia from the LHM tank to the pump due to an air suction leak.

I have a clear loop of hose connected on the main overflow return pipe (the second one back from the front of the tank) to monitor any bubbles returning from the pressure regulator to the tank.

In theory there should be none once the system is bled, but in my car there definately were intermitantly significant amounts of bubbles. In particular when first starting the car after standing overnight, or while bleeding the regulator, but also at random while the car is idling.

After replacing the hose it is no better, if anything it seems to have got even worse, even though I've confirmed with 99% certainty that the new hose is not leaking. (Brand new good quality hose, all the connections are tight fitting and have jubilee clips)

So am I now facing a faulty pump ? How likely is this ? How many different ways could the pump suck in air on the suction side ?

Am I likely to be able to solve any such leak by stripping the pump and renewing all the seals ?

Am I missing something obvious ?

The reason I'm searching for an air leak in the first place is problems with harsh ride and "bouncyness" which (sometimes) goes away after thoroughly bleeding the suspension and regulator, but always returns after less than one day.

The clear piece of pipe I'm using to watch bubbles in the return path does indeed seem to indicate the pump is sucking in air, but is there any way that this could be fooling me ? (False readings from an air leak in another return pipe for example?)

Regards,
Simon
Simon

1997 Xantia S1 3.0 V6 Auto Exclusive in Silex Grey
2016 Nissan Leaf Tekna 30kWh in White

2011 Peugeot Ion Full Electric in Silver
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Post by Homer »

Could be a leaky sphere diaphragm putting nitrogen into the LHM?
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Mandrake
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Post by Mandrake »

Possibly, but the accumulator sphere is only 6 months old, and the bubbles are present when the regulator is in the bypass mode - eg when the pump is just recirculating back to the tank, and in this condition the pump is isolated from the accumulator sphere.

So I don't think its that...

Regards,
Simon
Simon

1997 Xantia S1 3.0 V6 Auto Exclusive in Silex Grey
2016 Nissan Leaf Tekna 30kWh in White

2011 Peugeot Ion Full Electric in Silver
1977 G Special 1129cc LHD
1978 CX 2400
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Post by Dave Burns »

I would think that the only place your pump could be sucking air in would be via the drive shaft, if so the bulk of any such intake of air will be going to the power steering, for the obvious reasons.

Check out then the return from the power steering, if it runs clear of air then you have'nt got a pump problem, doing this will eliminate any possible confusion with nitrogen escape from the accumulator.

Dave
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Post by Mandrake »

Dave Burns wrote:I would think that the only place your pump could be sucking air in would be via the drive shaft, if so the bulk of any such intake of air will be going to the power steering, for the obvious reasons.

Check out then the return from the power steering, if it runs clear of air then you have'nt got a pump problem, doing this will eliminate any possible confusion with nitrogen escape from the accumulator.

Dave
Which hose is the return from the power steering though ?

I thought it was a seperate hose at the tank, but all the other return hoses are much smaller than the main one, also the main one has several other hoses joining into it.

It's not clear to me which hose it is...good idea to check it though if I can figure out which one it is.

Regards,
Simon
Simon

1997 Xantia S1 3.0 V6 Auto Exclusive in Silex Grey
2016 Nissan Leaf Tekna 30kWh in White

2011 Peugeot Ion Full Electric in Silver
1977 G Special 1129cc LHD
1978 CX 2400
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Post by goldfinche »

Hi It might pay you to very carefully check the actual plastic filter holder/tank top, thats a bit silly isnt it, cant think of the proper name, if there is one, had one with a crack in it and it was a swine to find. Only found it with a glass.
Have had a leaky sphere before now.
Cheers Geoff.
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Post by Dave Burns »

Follow the return from the pinion valve to its location at the reservoir.

Dave
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Post by Mandrake »

goldfinche wrote:Hi It might pay you to very carefully check the actual plastic filter holder/tank top, thats a bit silly isnt it, cant think of the proper name, if there is one, had one with a crack in it and it was a swine to find. Only found it with a glass.
Hi,

Thanks for that, yes a crack in that tube did cross my mind. To eliminate it as a possibility as a test I tried simply poking the end of the new hose I was installing into the tank through the top filler hole, thus eliminating the feed tube completely - no difference at all.

Regards,
Simon
Last edited by Mandrake on 30 Apr 2006, 11:56, edited 2 times in total.
Simon

1997 Xantia S1 3.0 V6 Auto Exclusive in Silex Grey
2016 Nissan Leaf Tekna 30kWh in White

2011 Peugeot Ion Full Electric in Silver
1977 G Special 1129cc LHD
1978 CX 2400
1997 Xantia S1 2.0i Auto VSX
1998 Xantia S2 3.0 V6 Auto Exclusive
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Mandrake
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Post by Mandrake »

Dave Burns wrote:Follow the return from the pinion valve to its location at the reservoir.
Easier said than done!!! :lol:

I think one of the books I have might actually have the pipe routing to the tank so I'll have a look at that tommorow. Thanks.

Also I wonder if I'm being a bit too fusy.... sometimes the bubbles I can see are tiny (although lots of them) but as far as I can tell there should be ZERO bubbles, and any bubbles are a sign of trouble ? Especially when the number and size of the bubbles seems to vary randomly.

(After all they will eventually collect and build up in the suspension, especially on an anti-sink model where it doesn't self bleed from going down over night)

Regards,
Simon
Simon

1997 Xantia S1 3.0 V6 Auto Exclusive in Silex Grey
2016 Nissan Leaf Tekna 30kWh in White

2011 Peugeot Ion Full Electric in Silver
1977 G Special 1129cc LHD
1978 CX 2400
1997 Xantia S1 2.0i Auto VSX
1998 Xantia S2 3.0 V6 Auto Exclusive
goldfinche
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Post by goldfinche »

Hi its me again,getting a bit slow nowadays, came across a crack in the stub brazing on the pump at one time, lot of very very small bubbles does indeed sound very much like a sphear leaking N through the diaphram this can go on for weeks, best of luck.
Cheers.
Geoff.
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Post by Mandrake »

goldfinche wrote:Hi its me again,getting a bit slow nowadays, came across a crack in the stub brazing on the pump at one time,
Do you mean the inlet tube on the pump ? Mine doesn't appear to be brazed, it looks like its just an interference fit in the housing.

Regards,
Simon
Simon

1997 Xantia S1 3.0 V6 Auto Exclusive in Silex Grey
2016 Nissan Leaf Tekna 30kWh in White

2011 Peugeot Ion Full Electric in Silver
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1978 CX 2400
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Post by AndersDK »

Hi Simon -

Xantia owners have previously reported on leaking pumps here. Leaks from the pump body that is. Caused by snapped housing bolts or cracks in the body parts.
The earlier wellknown BX/CX pump type failures does not seem to apply here as the Xantia/XM pumps are of a totally different design. A much more DIY repair friendly design I'd say.
Anders (DK) - '90 BX16Image
goldfinche
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Post by goldfinche »

Ah maybe the pump that I came across had been got at, yes it was the short inlet pipe on the pump body which was metal and it had been brazed in. I could be wrong but I'm sure that I heard of a pump with a plastic body that was supplied for a short time. Anders will know I'm sure.
Cheers.
Geoff.
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Post by Mandrake »

AndersDK wrote:Hi Simon -

Xantia owners have previously reported on leaking pumps here. Leaks from the pump body that is. Caused by snapped housing bolts or cracks in the body parts.
Hi Anders,

Do you mean one of the main long bolts that is visible from the outside snapping and thus allowing the pump housing on that side to open slightly along the join ?

If so I should be able to see this from the outside, right ? Or would I have to try torquing the housing bolts slightly to see if they hold firm or turn freely ?

If the problem is a crack, is it likely to be repairable ? (Even if I get an engineering shop to make a small repair it is going to be MUCH cheaper than a new pump)

Were there also any mentions of the seals being a possible source of leaking as well as cracks or damaged bolts ? I'm sure I remember somebody saying they had a leaking shaft seal but I'm unable to find that thread...

Regards,
Simon
Simon

1997 Xantia S1 3.0 V6 Auto Exclusive in Silex Grey
2016 Nissan Leaf Tekna 30kWh in White

2011 Peugeot Ion Full Electric in Silver
1977 G Special 1129cc LHD
1978 CX 2400
1997 Xantia S1 2.0i Auto VSX
1998 Xantia S2 3.0 V6 Auto Exclusive
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Post by AndersDK »

Hi Simon -

Yes
&
Yes
&
Yes

Me thinks it was the old style pump leaking from shaft seal as this is certainly prone to do that after a long service life.
Anders (DK) - '90 BX16Image
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