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[beamish]

On the road today on Classic Efi on which I have travelled many a mile. Touch rear i.e. foot brake and it locked the rear wheel and would not release! Result 20 yard slide. Could not fathom why. Slackened brake rod and continued on way resolving not to use rear brake. 8 miles on and brake is binding, but this time gradually, but still brings me to a halt with smoke from drum. Release rod even further and make it home. BUT why so sudden and in first instance could have been catastrophic. I'll have a look inside ASAP but what do you think I'll find?!

[Paul M H]

Only time I've had this happen was when the brake hub securing bolt/anchor bolt snapped allowing the brake hub to turn with the wheel and even bending the brake rod it locked the brake solid whilst I was riding over the Hammersmith flyover at a fair old speed. Nice big skid lucky i stayed on the bike and it was a dry day that was a hell of a shock

[Paul M H]

P/s should of added that was on and old bullet iron barrel so same may not apply to modern bikes as im not sure how they are set up.

[beamish]

Thanks, but the puzzle is that I can't spot any external damage nor reason for the sudden siezure. Mark, what you describe happened to me on my DOT many years ago, but I could immediately see what had happened and why. I.e. my failure to properly secure the brake anchor. I'll get the back wheel off and investigate sometime soon

[vince]

Hi, the two bolts holding the cam bush have loosened allowing the brake to jam on. You will probably find the backplate is now distorted. Vince

[beamish]

Sorry, I meant Paul, not Mark.

[beamish]

Thanks Vince,...I think!

[Adrian]

As far as I can tell the EFI drum rear brake is the same as the earlier models, except that the wheel has been flipped over for the new chain run and the brake operating arm is longer.



As part of your checks you might find the brake cam spindle has partly seized in its housing. I bought a Redditch Bullet a few years ago that had been in storage and the wheels would hardly move. Once it was all stripped, cleaned and a small dab of crease smeared on the cam spindles it all worked fine.



A.

[Tim NZ]

Paul M H:


It is not at all an uncommon fault, and in extreme cases can result in buckling the swing arm too...


Some times it is metallurgy (Sheared torque stay) but more commonly is the initial direct result of excessive servo action in the brake shoes.


Leaving the brake cam to Float may be OK with the 6" SLS front break, but not in the rear as has been advocated here in the past.




With a fixed pivot (un-adjusted/corrected) SLS brake, inadvertently switching brake shoes about can result in dire consequences, especially if done to the front brake. The potential for excessive servo reaction can lock the brake in an instant!!!

[steve hunt]

H'i this happened to me luckily just round the corner from home, when I striped the back wheel it was one of the brake shoes had broken off and jammed the brake on. It bent the back plate as well as the anchor mount on the swing arm.steve