Xantia Hdi - brakes 'hanging on'

neil2 · Post by **neil2** » 28 Dec 2003, 03:09

Problem - Xantia brakes. They're not binding (they were, but have been freed by dealer and I've had the car on a wheel-free ramp to check they aen't now) but are now 'hanging on' - ie they apply as well as ever but take 3-5 seconds to release fully, during which time the car is notably sluggish under accelleration or will 'hill-hold' stationary on quite a substantial slope. Once they do release fully they're fine, but its very irritating. Any idea? Dealer baffled - well there's a change! Fortunately it's still under warranty, so they can continue to fault-find by changing expensive lumps at Citroen's expense but I'd rather we got to the bottom of this quickly! Thanks in advance.

jeremy · Post by **jeremy** » 28 Dec 2003, 04:40

Sounds like air in the brake pipes. Press brake and fluid flows into pipes normally but continues to do so until the air is compressed. release brake and air has to force oil out to release brakes.
You probably need to bleed all brake calipers until the air has been expelled. The next and more interesting question is how did it get there as most gas in the system (from sphere leakage etc) simply by-passes the dead end brake circuits and is expelled harmlessly.
jeremy

neil2 · Post by **neil2** » 28 Dec 2003, 06:07

"How did it get there"... Hmm!
It's just had the rear spheres replaced (well, twice actually, they put saloon ones on the first time which turned it into a very strange device!) by a Citroen dealer.
Could that explain air in the system?

jeremy · Post by **jeremy** » 28 Dec 2003, 14:42

Probably - gas has probably escaped from the old spheres as well.
I suppose o my BX i discharges when the car sinks - but of course you have anti-sink and so it probably doesn't just go away.
Its worth trying some 'cit-aerobics' to see if it makes any difference. Simply start the car and raise it to full height and drop it a few times - this will cause fresh LHM to be pumped through the suspension circuits and with luck the old fluid will carry the gas out with it. If there is a lot of air - repeat it after a few hours just in case there is air dissolved in the oil.
Remember the rear brakes are fed off the suspension circuit - so air in the suspension may affect the brakes.
If this makes no difference then the air has got into the brake lines and the brakes will have to be bled.
jeremy

neil2 · Post by **neil2** » 28 Dec 2003, 16:46

Thanks Jeremy - sounds like a job for the dealer, not because its hard but because they seem to have caused it! I don't mind getting dirty to fix something of my doing, but I'm certainly not doing their job for them. Good to be armed with the right info though - much appreciated!
Neil