Rear Brake Lock up

[alan_nc]

Rode in a Trial last weekend on my 74 TY250A. 3 Sections had creeks, so I was in the water 9 times (dumped it one of those times).

My problem: After about the third wetting my brakes would lock up and not allow we to move the bike backwards - moved forward fine. I assumed the glue on one of the shoes had softened and the shoe had come loose. This has happened to me before and the shoe then comes over the other shoe and locks the wheel up. Not so this time.

I have everything apart and there is nothing (that I can see) that would cause the wheel to lock up on either forward or backward movement. It does appear that there are grind marks on the side of the shoes (internal side)very slight.

I have cleaned everything within an inch of it's life and am ready to reassemble but hate to do it without really fixing the problem.

Any thoughts?

Edited June 29, 2011 by Alan_nc

[dombush]

Hi

was there originally a grinding noise or gritty feeling during the move backwards before locking, or did it immediately lock up whatever the position of the wheel ?

Now that you have cleaned it out is it still locking?

The reason i ask is that if a stone crept into the drum during the submersion it could lodge between a casting web in the drum and one of the brake shoes...

just a thought

Dom

[alan_nc]

That might be a possibility. Between the noise of the TY and the other Trials bikes I never heard anything unusual.

[charliechitlins]

I came across this once in the murky recesses of my past, but don't remember just what it was.

Maybe something to do with excess play or flex in the shackle that holds the drum...allowing the drum to move and the brake rod would push the arm....or something...

I'm pretty sure it had something to do with the shackle permitting the backing plate to move too much.