My TLS drum brake has been reworked on a lathe, brake shoes also adjusted and a stiffening kit added. Everthing is lubed with copper paste. When I roll to a traffic light or a stop sign the brake does not open up when pulled. This only happens at slow speed. (thankfully!). I have to pull the bike back a little when coming to a stop and the brake opens up. Maybe the shoes fit too well ? What can I do to prevent this?
TLS brake shoes normally have a large taper on the front of the lining and the lining is also shorter than on SLS brakes so you need to check the shoes against known good shoes. Also as the shoe springs new, old ones can sag and lose tension so they do not pull the shoes together fully.
I usually install a spring between the cable stop and lever to make sure the brake fully releases when it is first rebuilt. After using for a while you should be able to take it off. The inline switch causes some stickiness also.
Good idea with that extra spring!
My front brake cable is without inline brake light switch.
TLS brake shoes: well, I was not aware of the differences. The shoes came with the spare parts.
I bought the bike it as a basket case and used the shoes without checking.
Check the actuating cam and the ends of the shoes.
Is it possible that the cams/shoes are worn out to the point that the cam is going over center?
I saw something similar on a bike years ago. It turned out the cams were put in 180 degrees out. It was braking on the shorter side of the lobe. i.e. short side facing outwards.
When you say the drum has been re-worked on a lathe, I guess this has been skimmed to true it up. Obviously this makes the internal diameter bigger and this can let the cams go over the optimum angle and get wedged. The best fix for this is to get thicker linings fitted and make sure they are a close fit all around the drum with the cams at rest. The relining company should have the whole wheel to get the linings accurate.
I have rebuilt a tls brake with the cams out 180 degrees!, easy to do. Also cam wear and a dry plate bush can give problems.
Today I fiddled around with brake adjustments. I lubed the cams, cable etc. Still locking up.
So I pulled out the brake , grabbed a file and tapered the brake linings a bit more. I also used copper paste for lubrication on the brake shoe pivots. First short testride showed better results, no sticking at low speeds. Hopefully solved the problem.
Thanks for all the hints!