Pulsing rear brake

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Silverspur
Posts: 34
Joined: 16 Oct 2018 17:21
Location: London

Pulsing rear brake

Post by Silverspur »

Has anyone come across a rear drum going out of round?
My Strada's rear brake appears to pulse on and off at slow speed such that, with the rear brake, I cannot bring the bike lo a halt without a lurch. It works fine when up to speed. It feels just like a warped disc.
I've got the wheel off the bike but I cannot a get my dial gauge inside the drum to measure whether it's round or not!
Any thoughts?
mbmm350s
Posts: 666
Joined: 22 Jun 2018 10:18
Location: Reading UK
Location: Berkshire UK

Re: Pulsing rear brake

Post by mbmm350s »

Hi,
Just to confirm for the benefit of those more knowledgable who can answer with more authority than I,
it is a rear drum, with wire wheels.
Mark
Richard
Posts: 48
Joined: 08 Jan 2018 17:04
Location: Doncaster, UK
Location: North Lincolnshire

Re: Pulsing rear brake

Post by Richard »

Yes I have, both front and rear. Thought that you would have left wheel on bike and turned it to test for runout. My fronts made the bike unrideable. Rear was causing a lurching feeling when coming to a halt, but no problem if used at speed when just slowing down a little.
Mine had been skimmed by previous owner, and when I tested with dial gauge there was little runout. Problem with skimming is that it removes chrome from high spots and leaves it on low spots and this alone causes pulsing. Replacement rear solved the problem.
Silverspur
Posts: 34
Joined: 16 Oct 2018 17:21
Location: London

Re: Pulsing rear brake

Post by Silverspur »

THanks, Richard.
It never occurred to me that the entire wheel could be oval! I assumed it would be the hub which is why I tried to measure the inside of the rotating hub with a (too big) dial gauge. And failed. If the entire wheel is out of whack I would have thought that it would need re-building rather than skimming, no?

Either way, I need an engineering shop somewhere near north London in order to get it checked out. Anybody know one?
'It must be a .....'
Posts: 365
Joined: 12 Sep 2010 12:25

Re: Pulsing rear brake

Post by 'It must be a .....' »

Hi, first have a good look at the drum as it could be some light surface rust on a portion of the drum braking surface from sitting/lack of use.
A couple of minutes with wet & dry might be the solution? De-glaze the linings and grease the pivots at the same time.
The brake operating cam's pivot could be worn (bush?) also the brake plate might be cracked at the cam pivot or even slightly bent.

Hope the solution is simple and cheap, good luck
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