Rear Brake Plate Movement

Hello - my rear brake plate is moving when the brake is applied and 'knocks' - basically I can see that the torque stop pin moving (vertically) when brake is applied which is causing a knocking when applying the brake when riding. It wasn't doing this prior to a recent tyre change but is now an issue. Do these stop pins wear and need replacement..?

When I spin wheel backwards there's no movement or issue on applying the brake but when I spin it forwards and apply the brake it 'clunks' as the torque stop pin moves up ever so slightly in the frame. I can move the brake plate up and down by what is only 2mm or so by holding the brake lever arm - everything is tightened up when doing so. It shouldn't do this surely...

Any advice very gratefully received as this is somewhat unnerving me.
I have a 1971 Commando btw with quick release rear wheel.
Many thanks,
Gunther

The torque stop pin is locked in place against the plate by a large nut on the inside of the brakeplate. So take the brakeplate off, dismantle the shoes to gain access to the nut and apply some blue Loctite and tighten. If the pin still moves then the brakeplate/pin is too distorted for the nut to keep it all in place, so either buy a new brakeplate or pin to restore tightness.




So parts 9, 10 and 13

However with the nut on the drive side done up to spec and the spindle on the timing side also tight the brakeplate should not move by hand, so likely you have the parts in the wrong order or missed a spacer out. The pin is still needed as the torque applied when braking is many times that of a hand.

Mine (torque stopper pin) got loose too.

Gunther said:

Hello - my rear brake plate is moving when the brake is applied and 'knocks' - basically I can see that the torque stop pin moving (vertically) when brake is applied which is causing a knocking when applying the brake when riding. It wasn't doing this prior to a recent tyre change but is now an issue. Do these stop pins wear and need replacement..?

When I spin wheel backwards there's no movement or issue on applying the brake but when I spin it forwards and apply the brake it 'clunks' as the torque stop pin moves up ever so slightly in the frame. I can move the brake plate up and down by what is only 2mm or so by holding the brake lever arm - everything is tightened up when doing so. It shouldn't do this surely...

Any advice very gratefully received as this is somewhat unnerving me.
I have a 1971 Commando btw with quick release rear wheel.
Many thanks,
Gunther

Click to expand...

What kommando said. But first, there should be very little "slop" between the pin and the swingarm slot. If there is, then determine if the pin or swingarm is worn and correct.

Most likely, kommando is correct and the pin is loose in the back plate, or the various spacers are not right. At any rate, to not ride until at least you know what's wrong. If that nut that holds the pin is loose or the rear wheel is improperly installed, bad things could happen. If that's all good and the pin and slot have too much clearance then hopefully you only need to change the pin and figure out why that happened.

It just sounds like a loose LHS spindle nut to me - Item 3.

Tightening the nut on the RHS secures one side of the wheel to the swingarm, but the LHS nut needs to be tight too.
Remember to apply the rear brake before tightening - it centres the shoes and makes for a better, less spongy rear brake.

BTW, Part 21 in the drawing is shown in a confusing way. If the backing plate rubs on the drum, then you need 21 and it goes behind the backing plate, not behind the drum. If it does not rub, then you don't need 21 but I've never found one that didn't need it.

Thank you all, that is a lot to think about. I have the whole thing apart now and the torque stop pin looks worn and wasn't very tight. The brake plate looks fine and not distorted. I am now trying to work out all the spacers, washers, seals etc to ensure all is 100% in the correct order - the diagram (thank you) is useful and I have it in the parts book but confusing to follow in places especially where certain parts are concealed with the hub of the wheel and the brake drum (between dummy axel and the cup washer) but I think I'm slowly making sense of it. I'll order some new seals / felt washers and the torque stop pin/nut and re-construct it all soon.
I won't be riding it again until all is well. In some respects changing that tyre has done me a favour in solving this brake issue!
I do love my Commando. Best wishes and I'll update soon.

Hello all - I’ve finally been able to re-build the back break set up. I replaced the (worn and loose) torque stop pin and added locktite to the nut/thread. All the spacers are correct and now in the correct order (they weren’t).

So the result is much, much better than it was - there is still a very small gap between the torque stop pin and the swinging arm slot it fits into but I don’t believe this should be a snug or tight fit?. The brake works well and rolling down my steep drive (engine off) it brakes progressively with no noise or knocking noise. When I ride it and there’s more force then there is an audible click I think (if I concentrate) as the torque stop pin moves against the swing arm slot - this also happens if I turn the wheel in the direction of travel with the bike on the centre stand. It’s only a very small click and not a clunking as before. I can also no longer move the brake plate with the brake lever arm, so that has been solved.

When riding the brake is effective and otherwise the ride is great. I couldn’t say if there was an audible noise from the torque stop pin previously (to the recent issues) as with engine and road noise it’s hard to tell - it’s there if I really concentrate on it but not the clunk / knocking that was there recently when the problem arose.

Does this sound OK you all. Have I fixed it..?

Many thanks,
Gunther

kommando said:

The torque stop pin is locked in place against the plate by a large nut on the inside of the brakeplate. So take the brakeplate off, dismantle the shoes to gain access to the nut and apply some blue Loctite and tighten. If the pin still moves then the brakeplate/pin is too distorted for the nut to keep it all in place, so either buy a new brakeplate or pin to restore tightness.

Andover Norton Parts Drawings - Genuine Andover Norton Factory Parts - Commando Parts

Andover Norton Parts are the only Norton spare parts in the market manufactured to original drawings, within the factory-approved tolerances, from the correct materials, and with the correct finish.

andover-norton.co.uk

So parts 9, 10 and 13

However with the nut on the drive side done up to spec and the spindle on the timing side also tight the brakeplate should not move by hand, so likely you have the parts in the wrong order or missed a spacer out. The pin is still needed as the torque applied when braking is many times that of a hand.

Click to expand...

Hello all - I’ve finally been able to re-build the back brake set up. I replaced the (worn and loose) torque stop pin and added locktite to the nut/thread. All the spacers are correct and now in the correct order (they weren’t).

So the result is a working brake - there is still a very small gap between the torque stop pin and the slot in the swinging arm it fits into but I don’t believe this should be a snug or tight fit?. The brake works well and rolling down my steep drive (engine off) it brakes progressively with no knocking noise. When I ride it and there’s more force then there is an audible click I think (if I concentrate) as the torque stop pin moves against the swing arm slot - this also happens if I turn the wheel in the direction of travel with the bike on the centre stand. It’s only a very small click and not a real clunking as before. I can also no longer move the brake plate with the brake lever arm, so that has been solved.

When riding the brake is effective and otherwise the ride is great. I couldn’t say if there was an audible noise from the torque stop pin previously (to the recent issues) as with engine and road noise it’s hard to tell - it’s there if I really concentrate on it but not the terrible clunk / knocking that was there recently when the problem arose.

Does this sound OK to you...have I fixed it..?

Many thanks,
Gunther