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Back brake problem

Posted: Sun Nov 10, 2019 3:02 pm
by boxofbits
Just re built a Spanish small block new shoes and uni hub threaded cable, it does have an remade arm so that could be one issue but when I brake its like it off and on judders will not bite as such at all. If I adjust it up yo much its rubbing any ideas pointers

Re: Back brake problem

Posted: Sun Nov 10, 2019 4:17 pm
by GTFOMWSC
boxofbits wrote: Sun Nov 10, 2019 3:02 pm Just re built a Spanish small block new shoes and uni hub threaded cable, it does have an remade arm so that could be one issue but when I brake its like it off and on judders will not bite as such at all. If I adjust it up yo much its rubbing any ideas pointers
possibly your hub is not circular could be slightly oval hence biting then not biting

Re: Back brake problem

Posted: Mon Nov 11, 2019 7:26 pm
by gaz_powell
Im not sure any hub and shoes match as perfectly as we would expect
I had the same.
You just need to work the shoes looking for the high spots - ball ache of a job but worth it.
Interestingly i bought a 30 quid hub for the vespa and new ebc shoes......perfect straight away .....

Re: Back brake problem

Posted: Mon Nov 11, 2019 7:41 pm
by boxofbits
Cheers also the outer cable seems really long how long should it be

Re: Back brake problem

Posted: Thu Nov 14, 2019 12:21 pm
by Warkton Tornado No.1
IMHO it's always worth putting a generous chamfer on the leading edges of the shoes & does no harm doing the trailing edge so that the shoes are interchangeable.

If time permits, the 'engine' can be used to bed in the shoes quicker, one method being running the bike on the stand with a jacked up rear end to allow drive. The brake should be set originally 'dragging' to allow for an accelerated bedding in period. Whilst this process takes place, the hub doesn't need the rim fitted, or the hub nut to final tightness, thus allowing easier removal for the inspection & very careful dust removal.

As soon as a consistent finish overall to both brake shoes has been achieved, the hub can be properly fitted.

BTW. The shoes & cam should have a good grease. Either a lubricant designed for purpose (Girling etc) or a Copaslip HMP type.

I hope this helps :)

Re: Back brake problem

Posted: Mon Nov 18, 2019 9:12 pm
by boxofbits
Thanks