Rode up to BMF no problemo (60 miles) On return ,after 10 miles rear brake caliper burns out for the second time . All I felt was a little lose of power and I knew from last time things were going the same way. Pulled over to find pads completely gone and discs blued. Manages to split caliper remove metal discs and proceed on journey . Anyone got any ideas. I confess that i did adjust the piston, as before the bike went through the MOT and nearly failed on the rear brake . I had put a new caliper complete, plus new rear master cylinder on a few weeks previously. 4D
How much clearance have you got between the activating rod connected to the brake pedal and the piston in the mastercylinder, also have you got a rear brake pedal return spring fitted.
On the ST (and maybe all Dukes) there's a screw insert on the front brake and clutch levers. It looks for all the world as if it's purpose is to adjust the span, but I know that if you dick around with it, the master cylinder piston doesn't come back far enough to let the fluid return when you let the brake off. That's in laymans terms, it may not be what really happens but the result is that the brakes tend to 'pump up' until they lock on.
I reckon that the rear master cylinder must work the same way? If any adjustment is stopping it return properly, the rear brake is going to drag pretty badly. If you think about it, brakes are more powerful than the engine, because you can slow down quicker than you can accelerate, and they do it all by using friction to turn the energy of a rolling bike into heat. That's a lot of heat. It wouldn't take much of a dragging brake at a constant 80mph to make the brakes red hot, wear down the pads and start weld metal to metal
I think Jools is right,it sounds like you went too far when you adjusted the "slack" out of the lever. I nearly did the same thing on the MTS.I adjusted the lever to where I wanted it but when I spun the rear wheel I could hear and feel the brake dragging on the disc.Best back it off then!
Thanks lads, Points taken,Hav'nt had much time to look at it ,but i thing maybe me adjusting the piston could be the way to go . It make sense. The return spring looks OK, Kev Ill have to fit another one and screw in the piston to its original position. Must admit the rear brake did work a treat though and thats a first. Regards 4D
you will find that it is you just resting your foot on the brake leaver put a bit more free play in problem solved, i burned my pads out twice befor i found out.