LHM leak at pinion valve

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Old-Guy
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LHM leak at pinion valve

Post by Old-Guy »

The Xantia's been dripping on the drive - not much but enough to make a mess. Got the chance to put it on a lift late yesterday afternoon for a quick look - the major problem is LHM leaking from somewhere near the top of the ?pinion valve block?. From underneath I can see two steel hydraulic pipes going into the bottom of this, both are wet with LHM with drops hanging from U bends. The LHM loss isn't serious (yet), but I need to fix it before long - no time at present.

I've had a quick Google search of the forum for appropriate posts, but I'm not much wiser on the likely cause, so can the Xantia experts advise please:
Given that the car is 15 years old but has only done 109k, what's the most likely cause?

Thanks in anticipation.

Please tell me that it's just another return pipe failed with age.
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Re: LHM leak at pinion valve

Post by Xaccers »

Cassy was leaking from there, Jim and I replaced the pinion valve. Oh it was such a fun job.
Talk to Martin at Plaeides and see if he can recon it or exchange it for a good one.
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Post by addo »

If LHM comes out when squewezing the rack boots, it's an internal leak. If it is oozing out the top seal (hose it clean with brake cleaner spray, then start engine and observe) then you need to at least renew the pinion valve internal seals.

Many simply leak from a failed return hose; this is relatively easy to renew, although if you honour the original routing it is a mongrel to feed up in the bundle of return hoses at the nearside firewall corner. You may want to make a brass or aluminium "tree" as it joins into a bunch of returns just below the tank.
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Re: LHM leak at pinion valve

Post by VertVega »

Old-Guy wrote:... Given that the car is 15 years old but has only done 109k, what's the most likely cause? ...
My Xantia had the same problem once. The seals of the pinion valve was the problem.
You can buy the Pinion Valve Repair Kit which have the seals and replacing will fix it.

I found a link from Japan describing the same job on a BX.
Have a look at this which would give some idea ---> Pinion Valve Repair of BX

Edit: Take a note of which grooves have O-ring.
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Re: LHM leak at pinion valve

Post by Old-Guy »

Thanks chaps.

I think I can rule out an internal leak as the pressure pipes to the pinion valve are wet to their gland nuts. In fact, from a prolonged wash with LHM, they and the pinion valve body look like new.

From underneath, I could only see these two pipes, so my next question is "Where does the return pipe come out of the pinion valve body?" I apologise for being lazy and for being slow with my thanks, but I'm very pressed for time at the moment.

Guy
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Post by addo »

It is the fatter black pipe shown here. You can see a slight drip out its end.

Image

Apparently racks are difficult to remove.
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LHM leak at pinion valve - FIXED

Post by Old-Guy »

FIXED
Loose flare-nut! :evil:
That's the third in the last 6 months or so!
For the benefit of anyone else with a leak in this area: -
On Wednesday afternoon I was able to borrow the use of a 2-post lift for a leisurely look with under-tray and O/S/F wheel all removed. There was LHM everywhere around the pinion valve - dripping off all the pipes, the rack boot, even the underside of the turbo's compressor casing! But the very top of the pinion valve body was clean and dry. I spent a while mopping it all up with large quantities of cheap kitchen roll. Having identified the 4 pipes:
the larger diameter pipe that comes out at the top (17mm flare nut), curves down and goes into a 'rubber' hose is the leak-off pipe (Thanks Addo),
the smaller diameter one (12mm flare nut) immediately below and to the rear of it is the HP feed from the pump,
the other two are the feed/return pipes to each side of the ram piston.
With torch and mirror-on-a-stick, I checked all the pipes for splits or signs of damage/corrosion - all appeared perfect.
Before dropping the lift to start the engine (for safety), I thought I'd just check all the flare nuts for tightness - starting with the HP supply. Loose! It's a bit of a pig to get at (half-a-flat at a time alternately from under the wheel arch and over the rack from the rear) but it was a good 3/4 turn slack. The exposed threads were dirty but not really wet, so I guess there was a fine spray coming out between nut and pipe. All the other gland-nuts were really tight.

Checking the pads while I was at it, I was annoyed to see that the outside O/S pad was nearly down to the backing (3 out of 4 crappy wear sensor wires rotted away!). Changed the pads this morning - no sign of LHM around the pinion valve. :) :)
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Re: LHM leak at pinion valve

Post by NewcastleFalcon »

I replaced the steering rack because of MOT "Centre front power steering component (s) leaking".

Not a nice job but I did notice when dismantling the various bits that one of my flare nuts was remarkaly easy to remove.

When the racks were off and I looked at them side by side there was nt any noticable difference.

I could probably saved myself a bit of work by tightening the flare nut up first.

steering rack pinion pics

Is there any logical explanation for why flare nuts come loose?

regards

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Re: LHM leak at pinion valve

Post by mirafioriman »

Yet again the old adage comes up trumps. 'Check the simple things first'.

I had a damp area on my Xantia once. I checked all the flare nuts and one was quite loose. Tightening it fixed that leak too. Perhaps over the years the seals shrink making the pipes loose?
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Re: LHM leak at pinion valve

Post by Old-Guy »

NewcastleFalcon wrote: Is there any logical explanation for why flare nuts come loose?
The flare nuts that I've had come loose were all what I would call High Pressure Supply (coming from the Accumulator or Pump at full pressure). The other flare nuts on the pinion valve were all up really tight when checked. I can only think that if a flare nut isn't done up quite tight enough, the cycling of temperature and pressure over time can work it slightly loose and LHM at 60+ bar will find a way to escape if it can.

Less than £20 for a complete set (8-17mm) of good flare spanners has turned out to be a sound investment - and the only way to obtain 12 and 14 mm sizes.
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Re: LHM leak at pinion valve

Post by jgra1 »

did mine (again last night oldguy)

I had a pinhole in one of the two short pipes from pinion valve a few weeks ago.. got another pipe made up but the leak returned.. back under last night and changed both pipes with a spare set kindly donated from Kenny on here.. did them up tight.. found that its a touch easier doing one pipe before the other..

fingers crossed.. LHM gets expensive after a while!
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Post by addo »

Does it what! I'm hanging to commission a metal return "tree" for the main return harness but keep needing the car - and hence it keeps bleeding as it drives...
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Re: LHM leak at pinion valve

Post by jgra1 »

seems to have made my hair nice and shiny though

if a bit green-rinse ;)
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Re:

Post by Old-Guy »

addo wrote:Does it what! I'm hanging to commission a metal return "tree" for the main return harness but keep needing the car - and hence it keeps bleeding as it drives...
IMHO there's a fatal flaw in the original design: because the 'tree' is upside down, a leak in one of the branches drains the LHM from all the others. The tree really needs to be above the reservoir with the trunk sloping down to it.
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Post by addo »

Good point. Even lying hozirontal would be better.

Fingers crossed I can start on it (redesign) next week. Nobody in town seems to have a tube beader, though.
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