Xantia 1.8i 16V 1996. It's got the 6+2 pump (one thick high-pressure hose in and two thin metal pipes going out to the accumulator/regulator). One of the thin metal pipes goes into the top of the hydraulic pump, nearest the pulley, it screws into the middle of a big nut. The big nut had been leaking a while which I noticed after checking the car as I'd found the LHM fluid level had dropped a fair bit over the week.
I cleaned the entire pump so it looked like new and started the engine, immediately I noticed that in time with the clicks from the accumulator valve, a thin film of LHM was welling in the recess around the big nut that has the thin metal pipe screwed into its middle. Only a small amount just in the recess but a couple of days later, I checked again and noticed that now the LHM leaking out was going all down the pump and dripping off. Not a terrible leak but enough to lower the LHM level over time.
So... Off to the Citroen garage. I went up to the parts counter, waited my turn and then as the fellow behind the counter acknowledged me I gave him a hefty slap to make sure he understood I meant business. I told him the part that was leaking and walked out with an 83p rubber 'O' ring.
Got back, left engine running and set to lowest setting, then waited a couple of minutes, switched engine off and unscrewed the pressure release screw a turn. After this I took out the smaller pipe going into the middle of the big nut and put it out the way, I then unscrewed the big nut and removed it, making sure to grab hold of and keep safely the spring that comes half-out as the Citroen Parts man had told me. (Incidently, I discovered I should have disconnected the high pressure hose feeding the pump from the reservoir, as syphon action made sure I had my bucket under the pump full of LHM before I could do anything else...).
Near the top of the nut's body there was an 'O' seal that I removed and inspected - it was "frayed" around the edge, not in the best of condition - and then cleaned the entire part, lubricated the new 'O' seal and nut with new LHM and put new seal in place. Before doing this I inspected the new seal to make sure it was perfect and it was.
Put the whole lot back together, etc and then started the engine. No leak visible so I was happy and gratefully returned inside to collapse quietly on the sofa.
Today I checked again under the bonnet after a good drive in it. Still no sign of leakage around the nut or on pump body, but I noticed that with each click of the accumulator, a slight glint of LHM becomes visible around the recess of the nut and then seems to get sucked back in again!
Aaarrghh, I grabbed my spanner, loosened the little pipe nut and then successfully managed to tightened the big nut with the new seal a tiny bit. Tightened little pipe fitting again and restarted the engine. Still there's a tiny amount of LHM visible in the recess every now and again. It's definitely better as it's nothing like before and hasn't yet seemed to come out further than the recess so at least it's not losing LHM now but still, I like things to be right and I also want this working perfectly before I start looking into why the back-end sometimes won't rise after having the car on the lowest suspension setting in case this slight leak is allowing air to be sucked in and somehow causing the back-end problem.
Why didn't the new seal do the job? The area where the new seal sits on the nut was clean and unmarked, the area it presses against inside the pump was cleaned by me and appeared flawless. Did I overtighten the nut in the first place and perhaps score or damage in some way the new seal? (I did do it up as tightly as I possibly could within the limited space...). And if I did overtighten it, how tight should it be, etc.
I just want to know why the bloody thing is still leaking ever so slightly before buying another seal and doing the whole thing again. It's so disappointing to do a job and find it's better but not right! [V]
Anyone who can help will automatically get their name entered into a free prize draw for a Mars bar. [8D] Terms and conditions apply. [:o)]
Thanks all, James.
Xantia hydraulic pump leak - help!
Moderator: RichardW
83 p suggests that you have the middle size of hydraulic seal. I have never inspected a Xantia properly but would have thought the pipes on the pump were of the largest size. there are 3 sizes of pipe used and naturally 3 sizes of seal. the smaller 2 are very similar to look at and the larger one looks - well large.
As I found out it is possible to get a seal using the wrong size of seal (too-small a seal).
When assembled properly the system is highly effective, forming a good seal without metal to metal contact etc. There is a chemical reaction between the seal and the LHM which causes the seal to swell and seal better.
Sometimes there seems to be a little dampness on the first couple of inches of pipe. If this is all it is I suggest there is nothing to worry about. I have known seals to leak if the pipe is not straight when it enters the fitting and assume this is due to a sideways force dislodging the seal.
So assuming you have the right seal and have made the joint carefully it should be ok. Dont try and wrench the pipe up really tight - but the joint does need to be fairly tight. Overtightening won't improve iit!
Jeremy
As I found out it is possible to get a seal using the wrong size of seal (too-small a seal).
When assembled properly the system is highly effective, forming a good seal without metal to metal contact etc. There is a chemical reaction between the seal and the LHM which causes the seal to swell and seal better.
Sometimes there seems to be a little dampness on the first couple of inches of pipe. If this is all it is I suggest there is nothing to worry about. I have known seals to leak if the pipe is not straight when it enters the fitting and assume this is due to a sideways force dislodging the seal.
So assuming you have the right seal and have made the joint carefully it should be ok. Dont try and wrench the pipe up really tight - but the joint does need to be fairly tight. Overtightening won't improve iit!
Jeremy
James -
I can do w/o the Mars bar - should I apply for it [:D][:D]
First :
The big rubber hose is NOT a pressure hose - it's in fact the opposite : the pump's suction (inlet) hose from the reservoir - therefore it's under vacuum. Also then the most common cause for air getting in to the system. The hose usually surface cracks on the pump stud - telling you it's time to get a new one.
This hose is a REAL bargain from your Citroen dealer :
Right now it's on sale for the reduced price of UK£130 - yes - amazingly the reduced low price of 130 - one-hundred-and-thirty [:D][:D][:D]
See this thread :
http://www.andyspares.com/discussionfor ... IC_ID=3835
Second :
The pipe leaking (and it's mate) - are the 2 pressure output pipes from the pump - carrying upto some 170bar - where the regulator cuts-out. Even higher on the pipe leading to the PAS servo.
No wonder even the slightest seal problem will leak out LHM.
The pipe nut/union & seal should seal correctly by tightening with normal hand force using appropriate tools.
It will NOT help tightening even further - because of the method of the sealing.
The way the seal works :
The seal itself is compressed by the pipe union nut - thereby pressing against both the pipe and the port hole internal walls.
The pipe has a small raised ring - to be held in place by the pipenut.
I suspect that the pipe itself is either oval or has a hairline crack - right where the seal is located.
I can do w/o the Mars bar - should I apply for it [:D][:D]
First :
The big rubber hose is NOT a pressure hose - it's in fact the opposite : the pump's suction (inlet) hose from the reservoir - therefore it's under vacuum. Also then the most common cause for air getting in to the system. The hose usually surface cracks on the pump stud - telling you it's time to get a new one.
This hose is a REAL bargain from your Citroen dealer :
Right now it's on sale for the reduced price of UK£130 - yes - amazingly the reduced low price of 130 - one-hundred-and-thirty [:D][:D][:D]
See this thread :
http://www.andyspares.com/discussionfor ... IC_ID=3835
Second :
The pipe leaking (and it's mate) - are the 2 pressure output pipes from the pump - carrying upto some 170bar - where the regulator cuts-out. Even higher on the pipe leading to the PAS servo.
No wonder even the slightest seal problem will leak out LHM.
The pipe nut/union & seal should seal correctly by tightening with normal hand force using appropriate tools.
It will NOT help tightening even further - because of the method of the sealing.
The way the seal works :
The seal itself is compressed by the pipe union nut - thereby pressing against both the pipe and the port hole internal walls.
The pipe has a small raised ring - to be held in place by the pipenut.
I suspect that the pipe itself is either oval or has a hairline crack - right where the seal is located.
James -
As I read this drawing - there is in fact 2 seals :
1 bottom O-ring for the larger insert nut (item 2 on drawing) - and 1 seal for the pipe (not shown) :
http://citroeny.cz/servis/bxser/cerpadlo_LHM_6+2.gif
(Can't make the pic show here using the usual img codes ?)
As I read this drawing - there is in fact 2 seals :
1 bottom O-ring for the larger insert nut (item 2 on drawing) - and 1 seal for the pipe (not shown) :
http://citroeny.cz/servis/bxser/cerpadlo_LHM_6+2.gif
(Can't make the pic show here using the usual img codes ?)
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Dave Burns
- Posts: 1915
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- Location: United Kingdom
- My Cars:
- x 2
You say the LHM only comes up to the recess and goes back down without ever coming out, well if it took 2500 psi to shove it out in the first place it sure as hell wouldn't go back in.
What you are seeing must be the residual oil around the pipe union being forced up as the pipe seal is compressed under all that pressure, if there was a leak it would be all over the shop again, and as said earlier it would not go back in, no way.
Dave
What you are seeing must be the residual oil around the pipe union being forced up as the pipe seal is compressed under all that pressure, if there was a leak it would be all over the shop again, and as said earlier it would not go back in, no way.
Dave
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JamesQB
- Posts: 375
- Joined: 13 Aug 2003, 18:01
- Location: North Wales, United Kingdom
- My Cars: Citroen Xantia 1.8 - I miss this car a lot.
- x 5
Thank you everyone who has replied. I'll be checking the car again shortly to make sure that there isn't fluid leaking out down the pump again. To clear things up, I'll just confirm that Anders is correct on this part:
"As I read this drawing - there is in fact 2 seals :
>>>>1 bottom O-ring for the larger insert nut (item 2 on drawing)<<<<
http://citroeny.cz/servis/bxser/cerpadlo_LHM_6+2.gif - This is the one I'm talking about. The LHM is welling up around the base of the head of this nut. I changed the O-ring which is marked as item 2 on the image.
This nut, as you can see on the image, is in fact a barrel with a hexagonal head on it. The bottom of the barrel presses against a spring which is inside the hollow of a piston-type part.
I thought that maybe this piston was able to pull the liquid back down inside but when the pressures are stated (as per Dave Burns) it does seem extremely unlikely. Hopefully it is just fluid caught in the recess being pushed up when the seal is compressed under that tremendous load and sinking back out of sight when the pressure reduces and the seal expands again. It makes perfectly logically sense. Thanks for that Dave.
I'll keep you posted on it.
James
"As I read this drawing - there is in fact 2 seals :
>>>>1 bottom O-ring for the larger insert nut (item 2 on drawing)<<<<
http://citroeny.cz/servis/bxser/cerpadlo_LHM_6+2.gif - This is the one I'm talking about. The LHM is welling up around the base of the head of this nut. I changed the O-ring which is marked as item 2 on the image.
This nut, as you can see on the image, is in fact a barrel with a hexagonal head on it. The bottom of the barrel presses against a spring which is inside the hollow of a piston-type part.
I thought that maybe this piston was able to pull the liquid back down inside but when the pressures are stated (as per Dave Burns) it does seem extremely unlikely. Hopefully it is just fluid caught in the recess being pushed up when the seal is compressed under that tremendous load and sinking back out of sight when the pressure reduces and the seal expands again. It makes perfectly logically sense. Thanks for that Dave.
I'll keep you posted on it.
James