Xantia - air in brakes ...

AndyP · Post by **AndyP** » 02 Oct 2005, 22:24

I bleed the brakes, they're fine and then they go spongy/pulsy again quite quickly. There always seems to be air in the offside rear caliper. Is it reasonable to assume that the sphere on that corner is leaking, or does the air just 'happen' to collect there ?

nick · Post by **nick** » 08 Oct 2005, 22:02

I can't offer much help, except to say that my Xantia does exactly the same thing! Always the offside rear calliper too, never the other 3.

Its been doing this for a couple of years, and I've replaced all 6 spheres in that time without it making any difference at all to the air collecting in the calliper. Mine only seems to do it in relatively warm weather, never in the winter, for some reason.

c7rlf · Post by **c7rlf** » 08 Oct 2005, 22:16

I had crappy brakes on my Xant when I bought it, The cure was to bleed a few litres of lhm from the rear brakes.

No bubbles appeared till i had filled a 2 litre container either side not really sure of where the air collects.
But the brakes have been fantastic ever since

KevMayer · Post by **KevMayer** » 08 Oct 2005, 22:40

Hey Paranoid,

You can still use your old name if you log on as Paranoid and then choose the option of "can't remember password".

They will email a new password to you. You can change the password in "edit Profile".

It worked for me.

Lets see you here as the Paranoid we're all familiar with.

good luck.

Kev

Mandrake · Post by **Mandrake** » 09 Oct 2005, 00:17

AndyP wrote:I bleed the brakes, they're fine and then they go spongy/pulsy again quite quickly. There always seems to be air in the offside rear caliper. Is it reasonable to assume that the sphere on that corner is leaking, or does the air just 'happen' to collect there ?

There is no connection between the sphere on one side and the caliper on the same side (but not the other) getting air in it - the oil from both sides of the suspension (both spheres) merges through a T junction or the hydractive control block before travelling up one pipe to the brake doseur valve.

On non-ABS systems I would say that the return from the doseur valve to the rear brakes is also one line which splits off at a T junction somewhere near the rear suspension chassis before going to each caliper.

On an ABS model then if it has independant rear ABS (does anyone know for sure on the Xantia?) then there may be two seperate pipes coming back from the ABS control block to each caliper independantly.

The main thing is though that there is a very long length of pipe that needs bleeding, and most people dont bleed enough oil. Connecting a pipe from the bleed nipple right back to the resoviour tank is the approach that some people use to get around it...(you can bleed as much as you like in one operation that way)

Regards,
Simon

AndersDK · Post by **AndersDK** » 09 Oct 2005, 12:19

Regarding the bleed process :

It is important to first do the Citaerobics removing air from the rear suspension. If not the rear brakes circuit will keep picking up air from here.

Rear wheels must not under any circumstances block during braking - or the car will loose steering immediately. Rather than riscing rear wheels blocking then both rear wheels are let free by almost any ABS system around. Also on the Xantia.

citronut · Post by **citronut** » 09 Oct 2005, 16:19

the way in which ABS works all four wheels have got to be indipendently suplied with presure,usualy its an acumalater sphere that dumps gas into the system that causes air in the brakes,so where xantias have other sphertes in the system besides on the legs and front acumalater,one of these could be the cause of air in your brakes
regards malcolm

c7rlf · Post by **c7rlf** » 10 Oct 2005, 16:38

Tried to be paranoid

!!!!!

But can't for the life of me can't remember the e-mail adress that I used can only presume it was the beer when I first registered

If any admin would like to restore me as Paranoid and send me a password I would be eternally gratefull

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