renewing SA drum brake performance

[GrasB]

I've got a drum brake which isn't performing nearly as well as it should do & had done in the past. I've taken the thing apart & cleaned it by lightly sanding the shoes & using some alcohol to clean the drum lining. After drying the whole lot out this has improved the performance a bit but not huge amounts, it's no where near as good as it was originally. What else would people recommend doing to get the brake working well?

 

[mickle]

I dont know. Im hoping this thread will provide the answer as i have a front wheel equipped with a useless SA hub languishing in the garage.

 

[mrandmrspoves]

Although SA hub brakes are quite robust and reliable eventually they will need a good service. Assuming that cables are running freely and tensioned correctly, and all parts are set up correctly mechanically, it may simply be time to replace the brake shoes. Old shoes can become glazed through overheating or just harden up over the years.. As you have nothing to lose - it may be worth taking the hub apart and wetting the brake shoes liberally, then seeing if there is any improvement over a few days. If no improvement - then invest in new shoes. SA sell service kits for about £25 - Try SJS cycles. ( note be sure to order correct size as SA made at least 2 size hubs.

 

[GrasB]

Although SA hub brakes are quite robust and reliable eventually they will need a good service. Assuming that cables are running freely and tensioned correctly, and all parts are set up correctly mechanically, it may simply be time to replace the brake shoes. Old shoes can become glazed through overheating or just harden up over the years.

But on an 18 month old hub?

 

[mrandmrspoves]

[/quote="GrasB, post: 2876530, member: 7408"]But on an 18 month old hub?[/quote

I would expect them to run problem free for much much longer than that - but IF everything else is set up correctly and working correctly, the only thing left to try is changing the shoes. My suspicion would be that something else is not correct, so I would take a close look to see how the actuation lever on the hub responds to the brake being applied and then see whether the wheel rotates easily when the brake is fully applied.

 

[GrasB]

So putting the whole brake mechanism & shoes in the old front wheel resulted in the old braking performance returning. The problem is the reason I replaced the front wheel was to install a dynamo hub on the bike, so the wheel that actually has decent performance leave the bike without working lights.

I think I'll need to make/find some kind of reamer to re-surface the drum on the dynamo hub.

 

[mrandmrspoves]

Are you certain that the two brake housings are the same size?

 

[GrasB]

Absolutely. In the manual all the part numbers for the drum side of the hubs are the same.

 

[mrandmrspoves]

....then I am as stumped as you are! :-(

 

[GrasB]

Okay so took the wheel apart & clamped the hub firmly in a lathe, took the smallest amount of metal off the braking surface of the hub shell until it didn't feel/sound gritty. Re-built the wheel & normal braking power has been returned. It's something I've needed to do on car disk brakes which have stood for longish period.

 

[mickle]

Okay so took the wheel apart & clamped the hub firmly in a lathe, took the smallest amount of metal off the braking surface of the hub shell until it didn't feel/sound gritty. Re-built the wheel & normal braking power has been returned. It's something I've needed to do on car disk brakes which have stood for longish period.

Good answer. Ill get my boy to take a lathe to mine too.

 

[mrandmrspoves]

Glad you got it sorted
.....and if I ever manage to wear the SA hubs out on my ancient old Trice, I will bear it in mind!

 

[fossyant]

Get real proper disks on your V8. Stop cutting corners.

 

[mrandmrspoves]

Get real proper disks on your V8. Stop cutting corners.

I never cut corners on my Trice - I have to go all the way round!

 

[GrasB]

Good answer. Ill get my boy to take a lathe to mine too.

The reason this works is because after standing for a while you get a light rust build up which pits the metal. You can wear through the pitted metal or lathe it off. If there is no sign of rust in the hub shell, mine had signs, then you may find that lathing the hubs doesn't help.

Get real proper disks on your V8. Stop cutting corners.

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