Calliper Problem

Tony Mundy · Post by **Tony Mundy** » 22 Mar 2004, 14:20

I changed the front pads yesterday on my 1994 Xantia 1.9td. Offside no problems but near side the calliper does not retract after applying the brake. I stripped the calliper down (there were no obvious signs of problems), cleaned it up and bolted it back to the car. But the problem still persists. My first guess is that the calliper is duff but because I am not up on Citroen braking system I am not %100 sure that the calliper is the problem. Any advice greatly appreciated.
Many thanks
Tony

Kowalski · Post by **Kowalski** » 22 Mar 2004, 17:54

Are you sure it is the piston that isn't retracting and not just the auto adjuster adjusting? Is the brake disc free to turn with the brakes off? If this is the case it's most likely that that is the auto adjustment mechanism working as it is supposed.

teabag · Post by **teabag** » 22 Mar 2004, 18:20

Hi,
I once heard of this happening. It turned out to be a flexible brake hose which had collapsed internally. The internal rubber was acting like a non-return valve.
Frankly its unlikely, but you never know.

bxbodger · Post by **bxbodger** » 22 Mar 2004, 19:40

Citroen callipers are no different to any others, its just the medium of operation that's different but they work in the same way, so the normal faults apply. The collapsed hose scenario is the most likely; it's quite common and easy to check; just undo it at both ends and blow through it; resistance should be the same both ways.
Is the brake binding a bit or fully stuck on? Quite often a new set of pads on a very worn disc can cause the brake to bind a bit, making it hard to spin the wheel freely; a hydraulic problem such as a flat hose is more likely to make the brake stick on firmly; you could also try sticking the old pads back in to see what difference it makes; it could be the piston is retracting but the pads are'nt, and are jammed onto the body of the calliper by rust, dirt, etc; the old ones would have worn their own groove.

AndersDK · Post by **AndersDK** » 22 Mar 2004, 23:21

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by bxbodger</i>

Citroen callipers are no different to any others, its just the medium of operation that's different but they work in the same way, so the normal faults ....
....
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Errrrrmmm ...[:I]
The caliper piston MUST be winded back in, exactly because of the handbrake adjuster mechanism.
- this is in fact rather special ...[8)]
If the piston at any time has been forced back in by tools - then the adjuster mechanism can be damaged - making for all sorts of trouble.

Norrie.com · Post by **Norrie.com** » 23 Mar 2004, 01:56

The O/S caliper on my ZX was binding slighty. The car had recently had new discs and pads fitted prior to me buying it. I did the following: remove the pads, move the caliper in and out. I had to tap it with a hammer to get it to move, but eventually it loosened up very slightly. Carefully lift up the rubber boots on the sliding bolts. Spray a little WD40 (using the tube attachment that comes with the tin) onto the bolts. Move the caliper in and out again, refit the pads. APPLY THE BRAKES to take up the 'slack'. This did the trick.

AndersDK · Post by **AndersDK** » 23 Mar 2004, 02:12

Norrie -
Your ZX brakes are different from Xantia brakes [:I]

noz · Post by **noz** » 23 Mar 2004, 02:28

Tony,
Another possibility is the mechanism between the foot pedal and the brake valve. I don't know the Xantia very well so bear with me. I'm sure someone who knows the car better will correct me.
On the XM there is a system of levers between the footpedal and the brake valve. One of the joints in this system is outside of the warm dry bodyshell and is prone to the weather. The joint gradually seizes and keeps the brake valve activated as if you had your foot on the pedal. For a reason I have not managed to decipher the brake pressure does not arrive at all the wheels at the same time. The drivers offside receives the pressure first. Seems implausible, I know, but believe me this problem is common to all RHD XM's. To fix the problem, find the offending stiff joint and grease well.
If of course, the Xantia is designed with the valve immediately behind the footpedal, please ignore these inane ramblings and I'll go back to sleep.
Cheers,
noz

Post by **RichardW** » 23 Mar 2004, 14:06

>If of course, the Xantia is designed with the valve immediately behind the footpedal,
It is [:D]
>please ignore these inane ramblings and I'll go back to sleep.
Night night!!