lhm leak

i3 · Post by i3 » 10 Nov 2010, 18:15

hey all, xants is leaking lhm from the hydraulic pump. i assume its leaking from the pump as there's green stuff on the alternator which drips onto the floor roughly below. on the floor beneath the car there is two areas where lhm spills...both close to each other, one larger than the other both roughly under the hydraulic pump. citroen said there are three different sized o-rings they sell, wasnt sure which it was so i got one of each. two are fairly small, and one is really quite large, i dont have a clue where the large one would fit onto. anybody have any pics or diagrams of where the o-rings are on the hydraulic pump, so i could establish where the leak is from. thanks all

DickieG · Post by **DickieG** » 10 Nov 2010, 18:25

i3 wrote:I dont have a clue where the large one would fit onto. anybody have any pics or diagrams of where the o-rings are on the hydraulic pump, so i could establish where the leak is from. thanks all

The leak is usually from the rubber seal around the outlet pipe union, here's a photo below.

Post by **CitroJim** » 10 Nov 2010, 18:29

hello isa, good to hear from you again!

The most likely place for leakage is from the delivery valve O ring as shown by the red circle and item 5 in the picture below..

It is easy enough to swap, albeit messy. Release the P clips on the pipe, undo the 12mm upipe union using a flare nut spanner (very important) and carefully withdraw the pipe, taking care not to bend it.

Then undo the 19mm hexagon and carefully lift the unit out, minding that under it is a strong spring and at the very bottom a ball and ball cup. It you lift the valve very carefully, the spring and ball/ballcup will not be disturbed.

Plenty of LHM will leak though... I find a baby nappy laid on top of the alternator is a good way to catch spilt LHM. If anyone was ever wondering, that's why there's a bag of nappies in my workshop!

Renew the O ring (which will be at the top of the threads on the valve body and reassemble.

Don't overtighten anything, especially the 12mm pipe union, it only needs to be nipped up.

Try to clean up the alternator as much as you can. LHM can hurt an alternator. If it is really full, take it off and wash it out using an airline and a gentle electronics solvent...

The picture will show where the big o ring goes...

Hope that sorts it, it's a very common leak...

Post by **CitroJim** » 10 Nov 2010, 18:33

Ha ha, you beat me to it Richard

citronut · Post by **citronut** » 10 Nov 2010, 19:29

also note that No. 4 is a smaller diamiter, so dont purchase the wrong one's,

regards malcolm

Xaccers · Post by **Xaccers** » 10 Nov 2010, 19:45

Handy thing I've found if the pipe weeps around the actual pipe that goes into the 12mm nut after you put it back together;
Slacken the bolts which hold the pipe brackets in place on the side of the pump, slacken the 12mm nut enough so that the pipe can wiggle, then pull the pipe up directly away from the 12mm nut, then nip the nut up.
This ensures the pipe's flare is seated properly inside the nut.

Jim/anyone, have you got the number for the large o-ring between the piston section and the bell end?
I'm thinking of replacing that on Juliet to see if it has the same effect as it did when Cassy's was replaced.

i3 · Post by i3 » 10 Nov 2010, 19:52

hey Jim, good to be back..problems as usual...ok...assuming that the diagram is showing the pump the right way up as it is in the engine, with alternator below it...the large o-ring is very big, it wont fit on any of those...however the larger of two small ones,looks like it will...so im assuming the huge one they gave me is not for the pump...?

Xaccers · Post by **Xaccers** » 10 Nov 2010, 19:58

the large one is most likely the one I'm after for Juliet.
It goes between the piston part of the pump and the bell end.

scratcher · Post by **scratcher** » 11 Nov 2010, 08:51

Hi, hint I was given , on putting things back together loosley fit the outlet pipe into the union nut before putting it back into the pump. Tends to avoid getting it in cross threaded.

Old-Guy · Post by **Old-Guy** » 11 Nov 2010, 18:42

Leaving LHM in the alternator is likely to lead to an expensive alternator replacement. Alternators for S1 Xantiae with the pump above the alternator are over £100 exchange; for those with the sensible arrangement with the pump at the bottom, the exchange price is under £50!

I presume Renault or Peugeot were responsible for the layout of the air-con engines and the Citroen engineers had to put the HP pump where they could?

i3 · Post by i3 » 11 Nov 2010, 19:15

hmm..it doesnt really look covered with lhm,,,however there are clear signs of lhm on the alternator...its been bit too rainy to try sorting the o-ring today...hopefully will be able to have a look tomorrow...

HDI · Post by **HDI** » 19 Nov 2010, 15:07

Need to replace the output valve and that blanking cap O rings on mine, they both weep, only very slightly but it really causes a mess over time.
Hope I have both sizes in my O ring assortment box !

Pshemsky · Post by **Pshemsky** » 10 Dec 2018, 14:08

Hi Guys.
I know that this topic is more than 9 years old, but i think that this could is my case and decide to join this discussion.
I've noticed that LHM weeping from one pipe connectors on pump itself. Just want to make sure that I'm thinking about same seal for my issue I decide to ask before I go any further.
Here's my problem - pipe with blue mark on it

As you can see, some lhm running down on pump right towards alternator :/

Post by **xantia_v6** » 10 Dec 2018, 17:33

It is very likely to be the 19mm o-ring that is leaking, I have needed to replace them on most of the Xantias and XMs that I have owned.

You could buy an identical replacement o-ring from Citroen, but I would recommend buying o-rings made in Viton, which is more heat resistant and has a longer life than the original o-rings, which I think are made from nitrile rubber.

In this application I also recommend slightly increasing the cross-section size (from 2.4 to 2.5mm) as I think that Citroen were a bit mean with their sizing, and the 2.4mm o-ring is a bit of a sloppy fit in the groove.

Here is one supplier of 2..4 x 19mm Viton o-rings: https://www.ebay.co.uk/itm/Metric-Viton ... rk:20:pf:0 I am just giving this link to illustrate that they are readily available, I have not used that particular supplier.

Pshemsky · Post by **Pshemsky** » 12 Dec 2018, 12:21

xantia_v6 wrote: ↑10 Dec 2018, 17:33 It is very likely to be the 19mm o-ring that is leaking, I have needed to replace them on most of the Xantias and XMs that I have owned.

You could buy an identical replacement o-ring from Citroen, but I would recommend buying o-rings made in Viton, which is more heat resistant and has a longer life than the original o-rings, which I think are made from nitrile rubber.

In this application I also recommend slightly increasing the cross-section size (from 2.4 to 2.5mm) as I think that Citroen were a bit mean with their sizing, and the 2.4mm o-ring is a bit of a sloppy fit in the groove.

Here is one supplier of 2..4 x 19mm Viton o-rings: https://www.ebay.co.uk/itm/Metric-Viton ... rk:20:pf:0 I am just giving this link to illustrate that they are readily available, I have not used that particular supplier.

Many thanks for quick reply. I followed advise and ordered 2.5mm, as mentioned above.
I'm guessing that whole operation need to be done after complete system depressurising (car suspension on low setting and release pressure - bolt beside acc sphere in front) ?

French Car Forum

lhm leak

lhm leak

Re: lhm leak

lhm leak

Re: lhm leak

Re: lhm leak

Re: lhm leak