Seized-Up Brake Calliper

Its a regular occurance on motorbikes.Take the caliper off its mounts,remove the brake pads, then keep pumping the pedal until the piston is forced out.It pays to have someone else there, as you can clamp the hose quickly, once the piston has been forced out to stop excessive fluid loss. If the piston doesnt come out that way (unlikely), then you may as well get a new caliper, as it will take an age to get it out. If the piston is corroded, then get a new caliper (I shouldnt think pistons are sold on their own). Remove the seals inside the caliper, and give them a thorough cleaning if you are re-using them.Thoroughly clean the caliper, especially the groove into which the seal sits.Usually corrosion in this groove forces out the seal, thus then partially seizing the caliper. If all this goes well, get some of the special brake assembly grease from a motor dealer.This comes in a tiny tube for about £2.Use that on re-assembly of the piston.Grease up everything else on refitting (people recommend copperslip,but I find the white grease is better), then bleed all the brakes, starting and finishing with the one you had apart. If in doubt about the condition of anything, then get a new one, I think they can be bought for £45ish new from a Motor factors. Alan.

Following up after reading the message agian, you say the rear caliper? Didnt they have drum brakes? If so, just buy a new wheel cylinder, they are pretty cheap new. If it is a disc, then see my previous post. Alan.

If it doesn't come out as Alan has suggested, you might try putting it in a vice and pushing the piston in a bit. This will at least free it and then it may come out by putting it back on the hose and pumping.

Rob Graham

I have a citroen AX 1989 so similar age. Both front brake calipers were performing very poorly to point I didn't feel safe in the car after I got it. I had a brake test and sure enough they said it needed 2 new calipers.

I would say if the dust membrane is in tack it's unlikely the weather has got in and caused any problems. In my case I had to hammer out the pins the brake pads where mounted on (I had to actually remove the caliper from the car to do this) and clean up the caliper where the pads where moving with a file.

It didn't help that the last person who changed the brake pads actually installed the retaining clips wrongly as well further restricting the pads movement.

After the change the brakes are great.

I can understan why a garage says a caliper has seized and needs replacing it just saves them work and for the customer it's probably more cost affective. But if you are doing it yourself and you have the time try cleaning it up first.

Thanks for all the suggestions.

It does have disks on the front and back. The rubber boot is fine on the piston that seized so I'll give it a pump in the morning. Before removing it, I will try pumping with it in position minus just one pad to see what happens. There are pistons on both sides and I wouldn't want the good one to take all the force and pop out.

If it goes wrong, there is a bike in the loft. I'll post what happens tomorrow.

Does it get worse after using the brakes, then eases off ? I have an Uno, and there was deterioration in the flexible pipe causing a blockage, and giving similar symptoms to a siezed caliper.

Graham

Thanks for the suggestion but it's definitely a seized calliper. The pad needed replacing and after eventually resorting to a drill to help get a stubborn pin out, thinking I was nearly finished, I was not happy to find that the piston would not move back to let the new pad in - even with considerable force from a crow bar.

Easier than undoing a nut! I just removed the pad next to the seized piston while her indoors came outdoors and contributed three gentle pumps as the piston freed itself.

Thanks for the help! __