Hitchcocks Forum

Hello



On my 2001 350 Bullet the rear brake recently became bit sticky - the pedal sometimes failed to come back up. so I a took apart the brake mechanism, lightly sanded the pads, cleaned everything in alcohol and applied a thin film of grease to the moving parts. That cured the sticky pedal, but now the brake squeals and grabs. It makes a hooting noise and it's hard to brake smoothly at low speeds. Even a little bit of pressure and it's like it's trying to lock the wheel. What have I done wrong?

When I first got my bike the rear brake was a bit like that the lever on the brake drum was set at the wrong angle and needed to come down a bit it was pointing at 3:30 instead of about 5 thinking of it like a clock also brake bar was all bent like a bow. I need to check the shoes properly soon but have my pedal set quite loose now it sometimes snatches and growls at low speed but only when the bike is cold and the first couple of times I try the brake.

As Lord- Toady has said. Try moving the lever one notch clockwise, this will increase the mechanical advantage. It will cause you to have to wind the adjusting screw forward along the rod, but this won`t affect anything. My bike`s rear brake did these things and did actually lock up so badly that I couldn`t move it, I had to push it backwards to release the brake. I pulled everything apart and, like you, couldn`t find anything wrong. When I reassembled it , it worked perfectly and to this day, I don`t know what I did to fix it.

If the brake is applied and works as expected when the wheel is spun backwards then the problem in all likelihood is the positioning of the brake cam. Something which definitely needs to be rectified sooner rather than later.

Apply copper slip to the pivot pin and the cam faces. The brake should operate with the cam faces parallel to the faces on the brake shoes, before the brake is applied. If it isn't the brake can lock solid.

Hi Daveh



I don't know whether this applies to you but - having tried to kill the Bullet Whisperer (once) and myself (several times and twice halfway up a mountain) - I have a theory regarding this sliding cam bush thing. I refer, here, to the modification which suggests allowing the cam bush to slide along the slot.



Sooo.. my theory having torn several brake plates to pieces - including one made from 6mm think stainless steel - is that, with 1950's shoe materials, this self centering action was a jolly good idea but, with modern shoe materials, it is not as the brake can too easily lock up, rotate the brake plate, cause a hell of an expensive mess, and also cause some excitement for any one who is following close behind.



I can offer no science, to prove that this is the case, but can tell you that since I screwed down and Loctited the cam bush, I have a good brake, by 1950's standards; zero lockups; and the contents of my intestines where they are supposed to be.

Your brake shoes may have become 'glazed', the braking surface looks shiny as if it has been polished. This often happens after the shoes have been in partial contact with the drum for a while, similar to the way you described the brake operation before. You can fix this by roughening up the surface by gently sanding with sand- or emery paper. Do not inhale the dust! There probably won't be asbestos in the linings any more but the dust is still harmful and best avoided.

REgards, Mark

Sorry about the boldness. Not sure what happened there.

@ Count Johnny, it actually highlights the important bit of your message, so thank the HTML fairy for that one!



Slackening off the cam bush for centralising/aligning the shoes on assembly and THEN nipping it up nice and tight makes sense.



@ Mark M, I'm pretty certain that all European brake lining material now has to be asbestos-free, but I can't say the same for Indian materials.




A.

My rear brake also 'hooted' when I applied firm pressure and felt like it was about to lock. There was still plenty of lining on them but when I fitted replacements the problem vanished.