Binding Front Brakes

Buchan Loon · Post by **Buchan Loon** » 22 Aug 2011, 09:46

Noticed that the front wheels are a bit warm after a run. Haven't had a chance to have a proper look but definitely need need handbrake cables as it looks like somebody's changed the pads without removing the cables and kinked the outers. Pretty sure that's not the problem though as the levers still go back to the stops. Do the pistons go sticky on these? And if so, is there any refurb possible or it it new caliper time?

Chris570 · Post by **Chris570** » 22 Aug 2011, 10:33

my 1.9td did this once, a good thump on the caliper released it and it didnt do it again. it was the handbrake peg sticking on mine though so i'd have a look at that. I can't remember how it comes out now but maybe if you get that out and give it a lube up?

Xaccers · Post by **Xaccers** » 22 Aug 2011, 11:03

Three rubber on the caliper shaft cash split causing it to seize up.
Take the retaining pin out and see how the caliper moves.

MJM · Post by **MJM** » 22 Aug 2011, 11:16

If both sides are equally warm after a run then it suggests that all is OK. (To get both sides to bind by the same amount would be difficult to achieve accidentally!) The Xantia is quite a heavy car and it doesn't take much to get the front brakes hot, and that heat creeps into the wheels.

Is the car easy to push on level ground with the handbrake off? Or will it roll down a slight incline easily?

Buchan Loon · Post by **Buchan Loon** » 22 Aug 2011, 12:41

Rolls easily enough but if you coast to a halt you can just feel a 'grab' as she stops. If you try to turn a wheel with it off the ground it takes more effort than I think it should, certainly more than other cars I've owned

DickieG · Post by **DickieG** » 22 Aug 2011, 14:47

How many clicks does it take to pull the handbrake on and when doing so can you feel the inner cable pulling through the outer or is it a case of little resistance then fully on if that makes sense?

kenhall1202 · Post by **kenhall1202** » 22 Aug 2011, 15:30

Binding front brakes on the XM can be caused by a lack of clearance or partial seizure concerning the relay lever which transfers the brake pedal pressure to the rubber button of the doseur valve (which being located in the XM front scuttle area means that these bits are exposed to the elements).

I am aware that the Xantia layout of the doseur valve differs from the XM but it may be worthwhile to check that the brake operating lever is fully retracting from the doseur button when the pedal is at rest.

Buchan Loon · Post by **Buchan Loon** » 22 Aug 2011, 16:12

DickieG,

I'm not with the car ATM but IIRC it's 3 or 4 clicks but a really long travel. Pretty sure it's not the cables as the levers are going back to the stops on the calipers

Ken,

Can the button be seen from inside the car or from the engine bay?

Gibbo2286 · Post by **Gibbo2286** » 22 Aug 2011, 16:47

More often than not it's the pad backplate rusted into the caliper frame. take the pads out and clean the rust off the edges and from the slots that they fit in so that they move freely.

What happens is that the piston has enough pressure to push them on but they don't come back off when the pressure's off., it wears the pads out prematurely too.

kenhall1202 · Post by **kenhall1202** » 22 Aug 2011, 17:40

Buchan Loon wrote:DickieG,

Ken,

Can the button be seen from inside the car or from the engine bay?

The Citroen Service diagram parts diagram shows the brake doseur valve mounted on the engine side of the bukhead and the operating lever and it's support on the cabin side, so i guess the answer is no. All you can do without dismantling is to make sure that the operating rod is moving freely.

I would second Gibbo2286's suggested check on pad seizure - they can become quite firmly stuck in the caliper. I always apply a smear of copper grease to all the pad and caliper sliding surfaces to reduce the chances of pad seizure.