Horrible experience: TLS brake locked

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Tom Bramler said:
Hello together,
I managed to have a closer look to my TLS-brake today - but the result is frustrating: no obvious mechanical failure found!
In detail:
  • Cable operation and linkages work perfect and smooth
  • Brake shoes are from RGM bought in 2015, lining thickness still around 4,8mm
  • No broken, detached or dislodged linings
  • No broken return springs
  • Cam surface as good as new, cam is far away to go over the centre
  • No rust or any loose debris in the drum
Nevertheless I had two minor findings:
  • Chamfer at the leading edge of 1 shoe is very small
  • Also on this shoe the contact pattern is not equal: to the inside of the drum is a strip which shows stronger wear
I found in my documents that I changed to the RGM "high friction" brake shoes (GF1091) in 2015 which really showed a better performance, but never locked - until yesterday.

I cannot believe that the minor findings above are the rootcause for the locking?!
Currently I see only one solution for the problem and to get confidence again: changing to a disc brake.
Thanks a lot for your intensive and motivating input
Regards Tom
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Interesting. Any update since? Are you still using this drum brake setup with some modifications, or none?
 
One of my friends was the first Australian soldier to be killed in Vietnam. A couple of years before he went there, he bought a new Suzuki Hustler. He gave me a ride on it. I'd been used to Triumph SLS front brakes. I rode his bike around the block and as I stopped in front of him, I gently applied the front brake which was TLS. The bike immediately jumped out from under me and ended up in it's side on the road. We picked it up, and there was not a mark on it. I often wonder if my mate ever forgave me for dropping his brand new bike.
His name was John Desnoy - he died at Fire Support Base Coral in about 1964. A Russian rocket got him. His older brother now lives in the USA, if he is still alive.
 
robs ss said:
I had not seen this thread when it was created.
I had a similar experience some 7 years ago and posted about what I found and did to prevent recurrence. It must have worked as I haven't seen any more issues - so (hopefully) here's a post I made about 5 years ago: https://www.accessnorton.com/NortonCommando/john-tickle-brake-springs.21523/post-321455
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Scary experience. Did you put a chamfer in since ? What friction material were you using? I only use Green Permatex lube on the pins. I have used White Moly grease but it tends to dry out over time? I am also replacing worn bare steel pins with new plated ones. The new pins come in Zinc plate but I will probably throw into my in Cadmium re-plate bin. Cadmium has a lower co-efficient of friction. The aluminum shoe on the stock bare steel pin has problems; I have dismantled two two brake plates where they where fused together.
 
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As I posted in another thread, the demise of drum brakes in racing and the switch to discs was not the result of inferior braking power, it was due to heat-caused loosening of the spokes. a properly-set up 4ls drum will haul you down like an anchor-at least until the spokes loosen. Of course, everyone knows now discs are simpler, easier to set up and require very little spoke maintenance.
 
oldmikew said:
I would suggest damp linings...
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That was my thought exactly. I replaced the lining on my 71 with shoes from Madass. Excellent fit and function but wet weather and low speeds can make it very grabby.
 
MikeG said:
That was my thought exactly. I replaced the lining on my 71 with shoes from Madass. Excellent fit and function but wet weather and low speeds can make it very grabby.
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This has been my experiance ,when the bike has been in the garage in wet weather and damp gets an opportunity to get into the linings
 
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