Rear brake binding.

[Irezumi aka Reuben]

Was putting on chain lube yeterday evening and found out the rear brake was binding. Adjusted the chain Sunday so it's happened between then and now. Stripped the caliper last night and found nothing wrong so put it all back together, today it was happening intermittently. Any idea's what could cause this that doesn't involve the caliper? What should I check bar obvious wear, which is ok.

Bike is a GPZ500S.

At the moment my soloution is to disable the rear brake so it doesnt damage the disk as I need to use the bike tomorrow and Friday.
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Pictorgraphicalfantastical

[Nath]

What do you mean by 'stripped' the caliper? Did you pop the piston out and look behind the seals? Normally hydraulic brakes bind because of corrosion behind the seals.

You say it happens intermittently... How are you noticing when it happens? If it's binding enough to prevent the bike moving easily then there is something seriously wrong, most likely with the master cylinder.
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Hard livin', hard luck.

[finpos]

The one thing to watch is that when you adjusted the chain, you moved the whole back wheel back a little bit. So if there is any problems with the various bits and bobs which mount the actual caliper (e.g. whatever it pivots on, the reaction arm etc.) being stiff or seized that could be the source ot the problem.

It's something you have to be extra-careful of if you have a mechanical linkage for applying the back brake.

finpos.

[Kickstart]

Hi

A Nath says, pop the piston out and clean behind the seals. Likely to take a while to clean it out thoroughly. Also clean out and lube the pins the caliper slides on.

Also worth replacing the fluid (well, err, not really a choice if you strip the caliper). Water in the fluid will get hot and turn to vapour, pushing the pads on slightly. However only going to have an effect after the brake has been used a bit.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Irezumi aka Reuben]

By cleaned I mean removed the piston. It was fine as a new seal was put on no more than 6 month's ago, nothing in there.

Had a quick overhaul and will see what happens, seemed ok this evening. Not binding enough to affect movement.

[irving]

[Nath]

[Kickstart]

Hi

I got some dental tools for the job. Worked well.

Seals can get damaged. They can also get contaminated and swell up.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing