Front Drum Brake Question

I just got this bike a short while ago. My front drum brake activated but did not grab at all no matter how hard I squeezed the lever. Everything external appeared to be moving and working as it should. I pulled the wheel and there was a thick layer of dust.rust adhered to both the shoes and the drum. I'm getting it all cleaned up. I also found the both the intake port and exhaust ports on the backing plate where intentionally blocked off. Someone did a very nice job of cutting some thin aluminum sheet metal to the exact dimensions and covering both the ports. It seems to me this is a problem as the dust has no place to go and you can not get any cooling air into the brake. What do the experts say?

The scoops can cause problems by collecting rainwater.

I’ve never seen bike brakes fill up with dust. I expect it finds its way out between the backplate and the drum.

The aluminum blanking plates were standard.
The brakes shoes are most likely worn out.

Drum brakes convert kinetic energy into heat which is absorbed by the mass of the brake drum ..... The air vents do little, if anything, to cool the drum mass, and can be closed off.

Slick

Slick[/QUOTE]

NASAman said:

I just got this bike a short while ago. My front drum brake activated but did not grab at all no matter how hard I squeezed the lever. Everything external appeared to be moving and working as it should. I pulled the wheel and there was a thick layer of dust.rust adhered to both the shoes and the drum. I'm getting it all cleaned up. I also found the both the intake port and exhaust ports on the backing plate where intentionally blocked off. Someone did a very nice job of cutting some thin aluminum sheet metal to the exact dimensions and covering both the ports. It seems to me this is a problem as the dust has no place to go and you can not get any cooling air into the brake. What do the experts say?

Click to expand...

There are 3 or 4 little holes in the corner of the inner drum face and wall that should be cleaned out. You can see them on the outside of the hub, between the 1st and 2nd ribs from the drive side. Toothpick sized.

The TLS drum brake can be made to work fairly good. First get new shoes. Make sure all the parts are there including the 'slippers' under the shoe ends or the cams. I think I used the high friction Fedoro from RGM or Commando Specialties if they're still in business. Upon assembly, glue some #80 sandpaper on the drum. Chamfer the ends of the shoes or grabbing will result. Assemble the front wheel without the 'slippers'. Loosen the axle and tighten the brake, you can use the adjuster. Tighten the axle with the brake tightened, centering the shoes in the drum. Make sure the 2 shoes come in contact at the same time using the TLS coupler. Now loosen the brakes, get the front wheel off the ground somehow and by hand turn the front wheel while gradually tightening the brake. At some point you will achieve about 90% contact of the drum and shoes. It will be fairly obvious on the face of the shoes, it doesn't take too long. Remove the sandpaper. Clean things up and install the 'slippers'. Re-assemble. Your front drum will now nearly be as good as the first disc brake Norton installed, but it will not hold up under constant braking, fading is a 'feature' meant to scare you.

Yes, those thin plates were installed at the factory. It really doesn't do much taking them off and it helps keep dust and water from the brakes. I didn't even use the new backing plate and am fairly happy with my early TLS brakes. It's better than dragging your feet which is what I used to do if gearing down wasn't good enough.

There is also a kit that keeps the shoes in better alinement, or you could sent it to Vintage brake and they will really get it to work as it should.

I used Dog's method and it works well. Be careful though good 80 grit removes brake material quickly. Brakes were a bit grabby at first so go carefully
early on.
Also sent my rear to Vintage and it is now so much better.

Actually it's norbsa's method. What does Vintage charge?

Re; “Someone did a very nice job of cutting some thin aluminium sheet metal to the exact dimensions and covering both the ports. It seems to me this is a problem as the dust has no place to go and you cannot get any cooling air into the brake. What do the experts say?”

You said it- the dust has to go somewhere, personally, I prefer open vents front and rear to help the cooling, unless you ride in a lot of water!

What is the word from those who have these brakes regarding the switch in the brake cable? I've read that replacing this with a one piece cable improves the braking but I don't know what one then does to activate the light.

T

rvich said:

What is the word from those who have these brakes regarding the switch in the brake cable? I've read that replacing this with a one piece cable improves the braking but I don't know what one then does to activate the light.

Click to expand...

This thread might help.

I won't bore you with all the trials and tribulations of 20 years of fiddling with my front TLS brake.
It was the removal of the switch in the cable that caused the brake to work - as in stop the bike.
It's now a bit of a novelty having a working front brake!
My basic problem was not being able to use a switch in the rear brake cable due to rear sets, but I've solved that too.
Sometimes I now brake and stop just for the fun of it!
By the way I'm not an expert - just somebody who has a working TLS front brake and a working switch (not in the cable) on the rear.
Bliss

Staytite said:

I won't bore you with all the trials and tribulations of 20 years of fiddling with my front TLS brake.
It was the removal of the switch in the cable that caused the brake to work - as in stop the bike.
It's now a bit of a novelty having a working front brake!
My basic problem was not being able to use a switch in the rear brake cable due to rear sets, but I've solved that too.
Sometimes I now brake and stop just for the fun of it!
By the way I'm not an expert - just somebody who has a working TLS front brake and a working switch (not in the cable) on the rear.
Bliss

Click to expand...

I'd be interested to know your rear switch solution for rearsets.

Hi Gadge,
As I'm not a VIP member I cannot post photos.
But I would consider the new part made by A-N 06 0482/SW. It looks neat, but is £29.95 + P&P + Vat
It was not available when I did my conversion.
I'm not sure how the switch works so it may cause the same effect on the back brake as having the switch in the front brake cable.
I believe only one brake light is required by law & for MoT. I prefer the rear brake light so I can flash it without actually braking.
Hope this helps

https://andover-norton.co.uk/en/shop-details/20513

Thanks for that. Yes, I've tried one of those. Wasn't impressed. Just trying to fit it and get it set up wasn't fun. No idea how would feel in use.

I've adopted plan B with a separate switch. Still work in progress but will try and add pics later. Busy playing with float heights currently.

https://www.accessnorton.com/NortonCommando/different-rear-brake-switch-location.10937/page-2

I have tried that on one of my cdo , cheap and work well........!

Didn't the original Proddy Racers have the switch mounted on the (vented) rear brake plate with an actuator bolted to the lever?
Haven't seen a decent close-up of one so can't be sure of the details.
I understand fitting the stiffening kit to the front drum makes an appreciable difference. I fitted one to my '70 Roadster/'S' (can't decide) but until I finish it and ride it I can't comment
Those inline switches are almost as legendary as the Triumph 'Comical' hub drum of the early '70s, although some claim they can be made to work...

This is my planned solution. The "mounting bracket" is a prototype but it works well statically. Not sure if it will stay put in use but hope to test soon. Will report back.