Which LHM pipe?

PeteW1959 · Post by **PeteW1959** » 06 Apr 2010, 19:21

Hi, my first post on here.

I have a '98 Xantia 1.9 TD which has an LHM leak. It is leaking from one of the unions to the pump, tried undoing it and cleaning but it is still leaking. I suspect it is fractured at the flare. Tthis is not the type of union which has a rubber seal as described in the Haynes manual, it is just like a normal brake pipe.

I don't know what to call the pipe when I ring up to ask for a replacement. The pump is, as far as I can make out, a '6+2' type and the leaking pipe is one of the metal ones which goes from the port nearest the pulley and down to the unit on the front of the engine at the bottom.

Anyone know what it is called?

Cheers
Pete

Xaccers · Post by **Xaccers** » 06 Apr 2010, 19:52

Is it leaking from the pipe itself, or from around the larger 19mm nut it screws into?

PeteW1959 · Post by **PeteW1959** » 06 Apr 2010, 20:01

It is leaking between the pipe and the 12mm union nut

Post by **CitroJim** » 06 Apr 2010, 20:55

That's an easy one. This leak is easily fixed by replacing one O ring that costs pennies from a dealer...

Undo and move the pipe out of the way (you must use a flare nut spanner on the 12mm union nut or you risk rounding it) and then undo the 19mm nut taking acre that as it comes undone there is a big spring underneath it. It is in fact a delivery valve and under it is a long spring , a ball, a ball cup and finally a piston. Allow the spring tension to let go gently and leave the spring in the pump body to avoid disturbing the ball, cup and piston. be prepared for a good spillage of LHM so protect the alternator.

Slip the new seal on, reassemble and job's a good 'un Just nip up the 12mm union nut. Don't overtighten it.

Part No. for the O ring is 4026 88

PeteW1959 · Post by **PeteW1959** » 06 Apr 2010, 21:16

Thank you so much Jim, you have just saved me a possible fortune!

Off to the dealers first thing in the morning.

Regards
Pete

Post by **CitroJim** » 06 Apr 2010, 22:04

Pete, I'm sorry, I was talking utter rubbish earlier on.

I thought you meant it was leaking from the bottom of the 19mm nut where the 12mm union screws in. Re-reading it now, I get the impression that it;s leaking at the 12mm union.. Sorry. I'm so used to leaks nearly always being caused y the O ring under the 19mm nut I went into auto-pilot.

Right, if it's leaking out of the top of the 12mm union nut and making the pipe wet it's not always the pipe that's at fault. It can be caused by a very flat accumulator sphere causing very high pressure spikes at the pump outlet that's enough to make the union leak.

Easiest way to check your accumulator sphere is to listen for a regular ticking sound from the pressure regulator (that;s the block the accumulator sphere screws into down by the gearbox). With the engine idling, you should hear a distinct tick from the regulator no more than once every thirty seconds. The tick is the sound of the regulator cutting out when pressure is reached. Ticks closer together than thirty seconds mean the accumulator sphere is low on pressure and ticks that are very frequent (almost like a ratchet) mean the accumulator sphere is ruptured. Under these conditions pressure spikes will occur and result in leakage somewhere.

Listen to the pump working. Whilst it is building pressure you will hear the pump working and then on the tick from the regulator you will hear the pump ease as it idles (just pumping LHM back to the reservoir). On falling pressure you will hear the pump go to work again until the required pressure is then achieved. You can hear the pump cycling just as you can hear a pressure regulator tick. The pump should spend most of its time idling and only working briefly to rebuild pressure. If it's working hard all the time this can cause leaks at the union and again points to a flat accumulator.

If the accumulator passes muster (i.e log tick intervals) then do assume the pipe is damaged. It's easy enough to repace as it runs between the pump and pressure regulator. Pleiades can make you a new one.

One very important consideration with the pipe is that all of it's "P" clips are properly in place. Due to the pressures this pipe carries, lack of, or incorrect, support can cause it to fracture very rapidly.

Again, I apologise for giving duff information although it is always good to have one of those O rings on hand as they do fail regularly and cause a very similar leak to what you have.

PeteW1959 · Post by **PeteW1959** » 06 Apr 2010, 22:12

Hi Jim,

Thanks for the correction.

If it helps diagnosis, the leak has got progressively worse, from having to top up the fluid every couple of months to now when I am losing a litre of fluid on a 10 mile run.

Regards
Pete

PeteW1959 · Post by **PeteW1959** » 07 Apr 2010, 12:52

OK, I've had a look and TBH I can't hear the regulator making any sound, but then again being a diesel it is difficult to hear anything other than the engine!

How loud should the tick be?

Also the pump seems to be working all the time, but again I am not sure what to listen for. What I am hearing from the pump is somewhere between a whistle and and a whoosh

, which seems to related to rotation speed.

Post by **CitroJim** » 07 Apr 2010, 12:57

Pete,

Another test you can do to confirm Accumulator healt is the "sit in the boot" test.

Immediately after switching off the engine, go and sit on the boot sill. Feel the rear end sink undser your weight.

After about 20s, the stored reserve of pressure in a good accumulator will correct the height and lift the rear of the car back to normal ride height.

If it does then the accumulator is reasonable. Get out and the rear end should go higher than normal following the removal of weight. If the accumulator is OK then the car will sink back to normal ride height after about 20s

If neither of the above happen, you can safely assume the accumulator is due for retirement.

Ticks can be loud or soft depending on the pressure regulator. Some are so loud they sound like a ten-bob watch and others are almost undetectable. Listen carefully and generally they are just audible over the clatter of a diesel.

PeteW1959 · Post by **PeteW1959** » 07 Apr 2010, 13:40

Thanks for that Jim,

I've done the 'sit test' and there is not much movement at all; sinks about 1cm when I sit on the boot, but then doesn't come back, and does not move at all when I get out.

I am going for a new accumulator first, because even if the pipe is still faulty, the accumulator is clearly past it's best. I have had to replace all of the suspension spheres within the last year, so it's a fair bet the accumulator has had it too.

Thanks for your help
Pete

Dommo · Post by **Dommo** » 07 Apr 2010, 14:19

CitroJim wrote:Pete,

Another test you can do to confirm Accumulator healt is the "sit in the boot" test.

Immediately after switching off the engine, go and sit on the boot sill. Feel the rear end sink undser your weight.

After about 20s, the stored reserve of pressure in a good accumulator will correct the height and lift the rear of the car back to normal ride height.

If it does then the accumulator is reasonable. Get out and the rear end should go higher than normal following the removal of weight. If the accumulator is OK then the car will sink back to normal ride height after about 20s

If neither of the above happen, you can safely assume the accumulator is due for retirement.

Ticks can be loud or soft depending on the pressure regulator. Some are so loud they sound like a ten-bob watch and others are almost undetectable. Listen carefully and generally they are just audible over the clatter of a diesel.

I tried this sit in the boot test Jim just out of interest, it raised up and sank twice before the anti-sink valve closed, I assume that is the sign of a good/ok accumulator sphere??

Cheers (and sorry for for the off topic post).

Post by **CitroJim** » 07 Apr 2010, 15:09

Pete, from that I reckon we can safely assume the Accumulator is due to be put out to grass now...

Try a new one and see if the leak stops..

Again, sorry for leading you up the garden path a bit last evening...

Dommo wrote:I assume that is the sign of a good/ok accumulator sphere??

That one Dommo, is shown to be in the very pink (or green). To do two sets of raises both it and the hydraulics in general have to be very fit. No worries there

Dommo · Post by **Dommo** » 07 Apr 2010, 15:19

CitroJim wrote:
Dommo wrote:I assume that is the sign of a good/ok accumulator sphere??
That one Dommo, is shown to be in the very pink (or green). To do two sets of raises both it and the hydraulics in general have to be very fit. No worries there

Super duper. I still think the rear corners need doing so they will get done once a tool is made up - think my brother said he could make one at work, which is good of him, other than that and the sinking overnight, the suspension seems fine - especially since cleaning and lubing up the front height corrector!

Thanks Jim.

PeteW1959 · Post by **PeteW1959** » 08 Apr 2010, 20:06

Accumulator sphere arrived today, fitted it (10 minute job) and Hey Presto! Still leaking

However, I can now hear the regulator clicking in and out, and the fluid only weeps out when the pump clicks in rather than a constant flow.

Guess I need a new pipe as well.

Post by **CitroJim** » 08 Apr 2010, 21:12

Pete,

I know this sounds a bit strange but I had exactly this on my V6, not because of a worn accumulator but due to duff hydractive electrovalve that bled pressure away very rapidly and this made the pipe union leak.

It still leaked after fixing the original fault.

I undid the union and loosened off the supporting "P" clips, then pulled the union out of the pump and gave the flare on the pipe and the seating in the pump a good clean.

I then reassembled, keeping the pipe at such an angle as to be able to screw the union nut in by hand all the way until it was right home. I then nipped it up a bit tighter and then tightened the "P" clips to hold the pipe firmly.

It should have made zero difference to the problem but nearly 10,000 miles down the road it's still dry.

I can't guarantee this'll work for you but it's worth a try...

At least you know you have a good accumulator now! You were lucky, sometimes they can be right devils to remove...