2000 rm 250 rear brake sticking

[rmrider45]

today drained all the fluid out of the rear caliper and put new fluid in . used a bleader tool and made sure all air was out. still after all of this the brakes are late and have to push all the way down hard to get 100% braking power..?AND SOMETIMES STICK ON :( what could be wrong caliper or master cylinder. looks as the caliper is working as it should .also where the caliper slides on to the bracket that the axl goes threw and onto the swing arm seems to have some play /up and down not sure if the part on the swinger should have say a rubber piece? not sure.. thx for any help on this :ride: :ride: :ride: :ride:

 

[rmrider45]

thx for any help on this

 

[arnego2]

I can imagine that you are being desperate but well anyway here it comes: Have you cleaned the pistons of the rear brake. Once they stuck they are dry, so if the pistons' surface is not lubricated they have a tendency to stuck.

How to repair: Pull the whole assembly take of the brake pads and push the pistons out one at the time. Take a socket or nut to block the other. Once out. Be carefull not to push them out completly clean them and use fine sand paper (1000 to 2000 grain) and polish the pistons. Use good grease to lubricate them and do the same on the other. All in all about 30 minutes to one hour.

I keep a old tooth brush in a grease can and use the it on the pistons and the chain drive.

 

[BSWIFT]

Replace the pin that the caliper floats on. If there is any ridge on the pin from normal wear, it will catch and prevent the caliper from expanding.

 

[WoodsRider]

Could also be the seals in the master cylinder are leaking. Had similar symptoms on a KDX once. Rebuilt the master cylinder and it worked perfect.