I have a problem with my brakes!
B31 mainly the front end 7” variety but the problem applies to the rear as well.
Spongy action etc. and the brake cam is a sloppy fit in the brake plate (what do you call that hole in the plate that it fits into?). I wanted to drill/bore out the plate and fit a suitable bush to take up the slack, however the metal seems to be particularly hard as my drill and reamers don’t make any impression.
Anyone got any ideas how I can sort this out? The 8” version has a cam bush that you can replace but not the 7” which has the offending part riveted onto the plate.
These are pictures of a chromed example but I have others with the same hardness problem which are not plated.

Cheers
Pete

email (option): petercomley@web.de

Pete,

Your brake plate cam spindle boss is not strong enough to bore out and fit a bush as the wall thickness will be too thin after opening out. Either remove this boss and make a new one to fit your cam or buy a new cam and fit to the original brake plate boss. Your spongy brakes are because of poor fitting shoes. I always fit the shoes to the plate with a suitable shim fitted under the shoe to cam at either side. Fit the brake plate on a mandril in a 3 jaw chuck and turn at slow speed the oversize linings to the drum size. You will be amazed how far out these shoes will be, once shims are removed the shoes will then have the drum clearance and your brake lever will feel hard. Don't forget to back off the shoes at the leading edge.

Tim W

email (option): t.j.walker@btinternet.com

And don't overlook wear in the handlebar pivot and the cable itself.
We tossed out a 100 meter roll of bowden cable because the outer was not wound tight enough so it would spring together rather than pull on the inner.
I have seen cheap Chinese made cable where the outer was rolled with round wire which creates the same effect.
OK for single strand cable like a mower throttle but won't work for high load braided or laid up inner.

You can also clean up the sleeve in the backing plate and then put a bush on or build up the brake cam and turn it down to size.
The grease passage does very little and you can live happily without it.

email (option): bsansw1@tpg.com.au

There can also be the problem of the cam spindle boss and or the brake plate flexing under heavy braking. I have two Velo's and Velo overcame this problem with a support plate between the cam boss and wheel spindle. Just a plate with two holes really. You can make it out here on my MDD. Ron

email (option): ronpier@talk21.com

I think I'm right in saying some WB30s have an outer support plate, I'm surprised they weren't used on the B31 as well?

Rob

email (option): robmiller11(a)yahoo.co.uk

The B31 has a support plate like that on the rear brake. It's really the front end that is causing me concern though.

thanks for all the suggestions!

Cheers
Pete

email (option): petercomley@web.de