Front brake binding.

[Rock10]

Took my kawasaki for mot last year. The bike passed its mot even though the front brake was binding.
The wheel would not spin freely. I haven't used the bike much and the mot is due again, so I have change the 4 pistons and seals in both calipers and also fitted tow new brake discs, bled the system with dot 4 fuild and the brakes are still binding, but not as much.
Any ideas would be welcome.

 

[Hann]

What bike which type of master cylinder?
There are two holes in the master cylinder, an inlet port and a much smaller compensating port.
The compensating port may be only .010" to .015" round so can be difficult to see, if it`s blocked the brake circuit will not allow pressure to be released and you`ll get the syptoms of sticking calipers. Check this port is not gummed up, you seem to have covered everything else.

 

[Rock10]

What bike which type of master cylinder?
There are two holes in the master cylinder, an inlet port and a much smaller compensating port.
The compensating port may be only .010" to .015" round so can be difficult to see, if it`s blocked the brake circuit will not allow pressure to be released and you`ll get the syptoms of sticking calipers. Check this port is not gummed up, you seem to have covered everything else.

Thank you for the information. I never considered the mastercyclind been the problem.

 

[theoneandonly]

sliding pins ? are they lubed ? red rubber grease NOT coppaslip or LM grease or vaseline
rubber brake hoses ? collapsing ? broken internally causing pressure to remain after release of the lever ?

 

[richh]

If it's on original rubber hoses, they've been known to deteriorate internally and restrict the fluid returning also.

Are the brakes actually binding hard? You will get some pad touching the disc usually, won't be totally silent when you spin the wheel.

 

[Rock10]

sliding pins ? are they lubed ? red rubber grease NOT coppaslip or LM grease or vaseline
rubber brake hoses ? collapsing ? broken internally causing pressure to remain after release of the lever ?

I replaced the pins when I fitted new rubbers and pistons.
Thank for your input.

 

[Rock10]

If it's on original rubber hoses, they've been known to deteriorate internally and restrict the fluid returning also.

Are the brakes actually binding hard? You will get some pad touching the disc usually, won't be totally silent when you spin the wheel.

If I spin the wheel It will not do 1 full rotation.
Thanks

 

[Rock10]

If I spin the wheel It will not do 1 full rotation.
Thanks

The rubber brake lines are the original from new.
There doesn't seem to be any restriction in the brake lines when I bleed the brakes.
I have removed the mastercyclinder and gave it really good clearing, I have a mastercyclinder rebuild kit on order. What I've found strange is the brakes are still binding even though there's no pressure on the pads.!!!@@

 

[sye]

Did you ensure that the grooves were meticulously clean when fitting the new seals? I use a dentists pick and cocktail sticks when I've had to do mine. Any contamination could lead to the symptoms you describe.

 

[Kenny]

Go for a healthy ride, the pads may just need bedding in.