Can a leaky hydraulic pump be repaired?

geoff_h · Post by **geoff_h** » 27 Nov 2005, 12:09

My L-Reg Xantia 1.9td (non-sinking suspension type, no air-con) has a leaking hydraulic pump.

(Symptoms are :- Brakes take 0.5 sec to react, then come on very hard.)

Before I remove the pump I would like to know if the existing one is repairable, so that if possible I can avoid buying a new/recon one ready to put back on.

So how do I know it's leaking? I removed the feed pipe from the reservoir and put an air line on it briefly. Even at pressures as low as 5psi this causes fluid to come streaming out between the mounting flange and the pump.

I remember on my BX, I saved a lot of money when didn't buy a new diesel injector pump when fuel started pouring out, but simply bought a new rotary seal.

Regarding the current problem with the hydraulic pump, I've never looked at one close up, but isn't the most likely cause of the leak a rotary shaft seal also?

Anyone know if that is indeed a comon failure mode and if so whether you can get a replacement seal (either thought motorspares trade or if not general engineering supplies)?

Most grateful if anyone more knowledgeable can help.

Geoff.

fatboyslimfast · Post by **fatboyslimfast** » 27 Nov 2005, 13:52

I don't think so, the pulley looks to be an interference fit. Best bet would be to take it to a diesel pump specialist to see if they can get it off and more importantly back on tight enough. I thought mine was leaking but after a good wash it wasn't (luckly).

Post by **Peter.N.** » 27 Nov 2005, 16:32

I think your best bet would be a secondhand one from the scrappie. A leaking pump is not a common fault but I have had one do it on a BX so I know it can happen. I have just replaced the one on my XM it was £115.00 plus vat from GSF, but they charge a whacking deposit, my total bill was £288.00! so I shall be hurrying back with the old one.

Mandrake · Post by **Mandrake** » 27 Nov 2005, 18:57

geoff_h wrote:My L-Reg Xantia 1.9td (non-sinking suspension type, no air-con) has a leaking hydraulic pump.

(Symptoms are :- Brakes take 0.5 sec to react, then come on very hard.)

Thats not a faulty pump symptom, thats a faulty accumulator sphere, and/or air in the brake lines.

Before I remove the pump I would like to know if the existing one is repairable, so that if possible I can avoid buying a new/recon one ready to put back on.

So how do I know it's leaking? I removed the feed pipe from the reservoir and put an air line on it briefly. Even at pressures as low as 5psi this causes fluid to come streaming out between the mounting flange and the pump.

Ah, but was it leaking when it was in normal operation ? Are you sure you're not creating a problem that wasn't there before ? Remember the inlet pipe of the pump is not designed to operate under pressure, it operates under suction. Applying positive pressure on the inlet is an abnormal condition, and the type of seal used may not take kindly to that.

I have a side on diagram of the original single output pump, but unfortunately I dont have one for the 6+2 pump used in the anti-sink models...

The older model pump has a press-in type seal on the shaft immediately behind the pulley itself.

Regards,
Simon

fastandfurryous · Post by **fastandfurryous** » 27 Nov 2005, 19:09

I have to agree with Mandrake here...

This is just air (or, more likely nitrogen) in the brake lines, and nothing wrong with the pump...(well, there wasn't anything wrong with it, but you may have blown the shaft seal by pressurising the inlet.)

geoff_h · Post by **geoff_h** » 27 Nov 2005, 20:32

>>Thats not a faulty pump symptom, thats a faulty accumulator sphere, and/or air in the brake lines.

See previous thread entitled "93 Xantia VSX Brake Problem".

- Summary - much deliberation about where the air was getting into the system, but consensus - most likely somewhere between the reservior and the pump. Finally fault was also traced to the pump flange in that case.

I should have said that I already suspected the pump or its pipe union because the area was moist with LHM and and some LHM "fling marks" in the area.

I felt putting some pressure in seemed like a good way to find out if I had the same failure without taking the pump off.

I don't think 5-10 psi would be enough to blow a shaft seal out of it's housing would it? And a good shaft seal would surely take more than that to cause a leak wouldn't it? If not it can't really be relied on to keep the air out when the pump kicks in.

Anyway leak rate returned to zero (moistness aside) afterwards.

The cross-sectional view sounds interesting. I'll bet the press in seal is a standard component even if Citroen won't sell it.

Thanks,

Geoff

jeremy · Post by **jeremy** » 27 Nov 2005, 20:39

With some confidence I can say that no-one posting on this board ahs been able to dismantle any Citroen pump and get it back together again. They can be done as they are reconditioned commercially but no-one here knows how. (we wish we did!) The same goes for the pulleys.

geoff_h · Post by **geoff_h** » 27 Nov 2005, 20:53

Thanks Jeremy, that's good enough for me. Looks like it's down to the scap yard (sorry, vehicle recycling centre) then.

Geoff

andmcit · Post by **andmcit** » 27 Nov 2005, 23:13

jeremy wrote:With some confidence I can say that no-one posting on this board ahs been able to dismantle any Citroen pump and get it back together again. They can be done as they are reconditioned commercially but no-one here knows how. (we wish we did!) The same goes for the pulleys.

I HAVE!!

At first it did dismantle itself though...

Two of the the three longitudinal through bolts decided the volume of high pressure LHM generated in the end bowl was too great to handle and gave up with dramatic consequences, "fun" when you're flinging a VSX TD around some single lane twisties flat out around the back lanes near the house!!

OK, the pump itself is very strightforward. I'm assuming my 6 piston FDV type will be generic enough to be the same as most others I've seen on various Xantiae. The end pulley drives the motive power into the the pump and is a separate interchangeable end section so it could be swapped around with another sized one dependant on the required pulley arrangement of your engine. The drive into the main pump body operates an offset cam which pushes the 6 obital spring loaded pistons away from the main shaft centre line. These pistons individually feed channels to the last section collecting bowl and out of the high pressure feed pipe.

The later two HP pipe pumps [which will be ALL post 93/94 cars] work on exactly the same priciple but I've not had the need to take one of these apart fully YET. I've stolen an end O ring out of a spare one as an immediate dodge to get the other dodgy one going mind, so can take it all apart and post piccies if anyone wants to see the pump's innards...

The through [longitudinal] bolts that shreared, thread right through the whole lot from the front pulley flange face to the end bowl. As with everything else Citroen these days it seems the whole assembly relies on an O ring on the pulley flange to the pump's main body and another on the joint to the end bowl. If either of these two O rings was duff believe me you'd know about it quick smartish - it wouldn't be JUST damp areas of LHM for sure!!

More likely in this case the culprit will be an O ring that sits beneath the main high pressure feed output pipe 'bolt/nut' that in real term is the size of a polo mint etc. I've seen a few with very noticeable leakage from this point. Citroen lists these on PR.net for a few quid each and they should be easily available.

The problem with my VSX TD so far as I can ascertain to this day was somewhere amongst either a sticking regulator, a flat accumulator and [being an early FDV car] an obstruction that reduced the effectiveness in the FDV. It's still not perfect but after 3 times of rescuing the car home and even rebuilding the whole lot at the roadside through the wheelarch, it doesn't 'go' these days.

Hope this helps,
all the best, Andrew

andmcit · Post by **andmcit** » 28 Nov 2005, 00:57

AndersDK · Post by **AndersDK** » 28 Nov 2005, 01:04

Andrew -

The earlier Xantia pump type is exactly the same design as found on DS, GS, BX, CX. Which is more or less a "sealed unit". These types have a pressfit housing with welded/moulded feed hose stud. The housing is held by an immense force of a large circular rubber seal pressing outwards on the housing.

On these earlier types the only safe way of removing the housing is applying moderate pressure to the feed stud. Best done using another (working) pump.
But the pulley will not survive any attemps using any standard DIY tools for removal. It is essential to remove the pulley for replacing input axle bearing and seal.

The later type pumps are a different design held together by bolts. But still the pulley is not easy to remove.

Mandrake · Post by **Mandrake** » 28 Nov 2005, 03:40

AndersDK wrote:Andrew -

The earlier Xantia pump type is exactly the same design as found on DS, GS, BX, CX. Which is more or less a "sealed unit". These types have a pressfit housing with welded/moulded feed hose stud. The housing is held by an immense force of a large circular rubber seal pressing outwards on the housing.

BX, CX and DS yes, GS and early ID's, no.

The GS had a single piston pump attached to the engine sump driven by a small crank inside the sump, which was (permanently) connected to the oil pump pulley shaft.

Just for completeness sake, as I remember painfully well how long a GS used to take to pressurize with that tiny little pump.

Regards,
Simon

andmcit · Post by **andmcit** » 28 Nov 2005, 08:36

I run an EARLY Xantia VSX Hydractive on a '93 and it has a different hydraulic circuit to the later cars in that it has a FDV, just like the Xm's system. That said it uses the same design of pump as the later Xantiae.

I can only refer to my experiences with these that's all I'm pointing out. Believe me - I know the sealed ones on the Cx's and Xm's to know the difference, but I thought this thread was about a leaking Xantia pump?

I still believe the leakage on Geoff's pump will be item 5 on the illustration I posted!

The single pushrod pump on the Gs is a bit puny isn't it - almost an afterthought!!

All the best,
Andrew

Mandrake · Post by **Mandrake** » 28 Nov 2005, 08:49

andmcit wrote:I run an EARLY Xantia VSX Hydractive on a '93 and it has a different hydraulic circuit to the later cars in that it has a FDV, just like the Xm's system. That said it uses the same design of pump as the later Xantiae.

Hmm, a 6+2 two output pump and a FDV in the same car ? Are you sure ?

The single pushrod pump on the Gs is a bit puny isn't it - almost an afterthought!!

I guess because it didn't have power steering they got away with it. From memory the pumping capacity was only 1cc per revolution and it ran at half engine speed

Not so bad when the car was new and it didn't loose pressure too quickly, (even so you were looking at about a 30 second lift up time from just overnight) but when the entire system got old and worn out and leaked pressure faster you could be in for a long wait. I seem to remember my Dad's GS got to the point where it was taking a minute and a half to lift up before it finally went off the road for rust reasons...

His was a '74 which didnt have the one way valves in the HP feed to the height correctors thus went down much faster and went down at the front first, whreas my '77 had the one way valves, and went down at the back first, much like a BX...

Regards,
Simon

andmcit · Post by **andmcit** » 28 Nov 2005, 10:30

Hmm, a 6+2 two output pump and a FDV in the same car ? Are you sure ?

Ok - semantics here - "That said, my car uses the same method of pump construction as later Xantiae" - yes FDV and ONE high pressure output pipe NOT TWO - a rare bird I kept being told when I enquired about a replacement pump!!

The Gs's pump does OK really - never felt it's under strength so to speak.

Andrew

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Can a leaky hydraulic pump be repaired?

Can a leaky hydraulic pump be repaired?

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