How to free up a seized caliper?

[Rabbitson]

Hi there,

I'm trying to change the discs, pads and fluid on my 1100GS and I've noticed that two of the calipers are seized in and I'd like to free them off (preferably without changing all the seals and dismantling the calipers completely)

Any tips on how I can persuade the calipers out?

David

 

[ebbo]

Do you mean “two of the ‘pistons’ are seized in”

Start on the seized ones, but I’d recommend doing them all while your in there.

Remove one caliper at a time, remove pins pads etc. Spray interior liberally with aerosol brake cleaner and clean up the caliper/pistons as much as you can, use a tooth brush to help.

Cut and place a piece of wood to fit snugly between one pair of pistons. Put a G clamp on one of the other pistons but don’t screw it down, its just to stop that piston coming out. This leaves one piston free to be pumped out.

Gently squeeze the brake lever, the remaining piston should move, even if it’s partially seized. Don’t pump it out too far; clean it up with aerosol cleaner and the toothbrush. Let it dry then apply a little brake fluid to the piston wall and seal as lubricant, then put the G clamp on it and squeeze it back in to the calliper, gently…

Clean up pads, don’t get the friction surface dirty, lube the backs and metal to metal surfaces with a light dab of copper grease, replace the pads in the same positions they came out of. Clean up all pins etc, treat with a light coating of copper grease before refitting.

Pump pads back fully on to the disc before riding off or you might get a nasty shock

Good luck

 

[Stan Pinn]

Thats some good advice, have a good go at this. A repair kit is £41 from BMW and a new caliper is £250!!!!!

 

[Blackal]

In lieu of cutting pieces of wood - you may just find that one of the sockets from your toolkit is the exact size to wedge between the piston faces.

Sockets are great things for pushing bearings out of pockets - if you happen to find the right size.

Al

 

[ELIMINATOR]

At work I use a hydraulic pump that goes up to about 1000psi, I have successfully blown out seized pistons on my Yamaha, and done the same for someone else on the Yamaha Diversion web site, his pistons were really bad, someone had tried welding a bar into the pistons (god knows why), but I managed to blow them out eventually. The dust seals had swollen & allowed corossion into the grooves, even though water pissed out where the main seals were also shagged, such is the volume of water that I can push through the caliper, it still blew the pistons out.

If you have problems getting the pistons out, pm me.

Ah, location deepest Benelux, perhaps this isn't viable then! where in europe are you?

 

[Rabbitson]

Hi there,

Thanks very much guys, I'll try some of those suggestions and let you know how I get on.

All the Best,

David