Changing Lhm, without depressurazing?

Hello

(first of all sorry if my english is a bit bad, i'm from Sweden and you know we swedes are blond )
I am eager to change my dirty LHM but doesent really have a good place to work or jack up a car, so it hasen't got done.
But then a citroen mechanic told me that I can do it without even loosening the pressure valve. He sad that I can probably do everything and only if the car doesent rise up after several minutes with the engine running i must loosen the screw.
Is this correct?


I surely be glad to not have to jack it up...

You'll get a PM...

Oh But we want to know what's going on, too

Read your PM.

I think you have to jack it up to release the preasure. You need to get so much LHM back in the reservoir as possible. It's not difficult but be sure to secure the car in the front. You know, a man's head between the car and the ground hurts...

There aren't many cm between the ground and the car in "low ride mode". It'd probably chrush your skull and then we don't have Perzy anymore and that would be tragic, wouldn't it?

Easiest way I've found is-

1. Put car in 'low' & let sink to the ground.
2. Turn off engine and leave a door or the boot open.
3. Chock wheels then pump brakes about 30 times to exhaust the accumulator pressure - this has the same effect as loosening the pressure release bolt.
4. Pump out the old LHM from the reservoir with a suction hand pump.
5. Remove reservoir and clean it. Clean filters.
6. Refit reservoir & filters and fill with fresh LHM.
7. Bleed brakes until clean LHM flows.

Takes me 1 hour tops now

I still think the good old PROPER way is to release the bleed screw on the regulator to release that little EXTRA air that can get trapped!!

This not a problem on 4 cylinder cars, Except 2.5 td, but a problem with the V6's and 2.5's as the regulator is SO WELL hidden from view..

Best bet - A set of ramps to lift the front up a bit surfice to get under to the regulator...


I nice procedure Wirdy.. I like it, will have to try it next time LHM needs dooing..


Rgds


C

Good points

I'd concur with citroenxm that a set of ramps are essential to maintain an xm at home and give so much more access to the hydraulic bits & pieces than axle stands do.
When doing my rear spheres on ramps I was able to remove the spare wheel & sit underneath the car with it on high to crack them. So much easier than grazed knuckles from the limited clearance you get when on axle stands.

You can get to it on the 2.5 by undoing the bolts holding the fuel filter housing to the battery box and moving it out of the way. There is then enough room to reach down to the regulator and get to the bleed screw from above (when I say enough I don't mean there is loads of room, just enough).

I'm not sure everbody agrees about that All these stupid questions...

Since i'm allready asking enoying questions I might continue

Why cant I just bleed all the LHM out at the brakes? Let's say I bleed the front left wheel, that should empty the resorvoar right? Then I can clean the filters , top up and be done.

Wrong?

Wirdy has it sorted. This is how i do it. Without a test set for modulating the ABS, it's the best you can do.

Wrong!

Unless you have about a week to wait for it to bleed out and risk starving the HP Pump, then NEEDING to essentailly undo the Regulator screw to bleed the air out..



Rgds

C

Never had a problem with air, keeping the feed pipe above pump inlet level and ensuring it's full before reconnection to the reservoir seems to work ok.

All you will get out is an accumulator full, unless you do it with the engine running and pumps don't like running dry.

Thankyou Derek, My point EXACTLY!



C