I fitted my newly built back wheel and fitted the brake pedal. Despite having loads of meat on the shoes I am taking up nearly all the adjustment on the brake road. The parts list shows 2 caps
ref 41-6078 on the 1971 Version of the Thunderbolt. I did dismantle the brake plate when I had it aqua-blasted, BUT I cannot remember if the shoes were fitted with the caps when I assembled the hub. Do they make that much difference ? Thanks.
If they are original shoes then the pads are essential. They sit on the pivot end of the shoe and are about 1/16 inch thick so have a significant effect on brake geometry.
If the shoes are pattern items I do not know.
Yes you will need them. They are a bit weird shaped which makes the edges that slip over the brake shoe 'clip' on, a bit like its got shoulder pads! The idea is the shoes become fully floating so centralise automatically. Note I use the word 'idea' as it should work in theory. In practice?????
Have a dig around in your box of bits and see if you find something close. If not they are available at places like Kidderminster M/Cs
Chris
In my experience with the Conical rear brake, the standard BSA pivot pads 41-6078 are not thick enough. Consequentially the brake lever has to turn past 90 deg to the brake rod rod before it begins to bite. You can fit a Triumph modified pivot pad 37.4037 which has a plate spot welded onto it to increase the effective thickness and take up the 'slack'.
I think this will sort out your problem.
Triumph service bulletin showing the modified pivot pad.
All answers appreciated. I have looked at many photos of this model, all the brake adjusters seem to have taken up much slack. Hope fully this tread may also help others. I am considering ordering new shoes with the modified caps from a Triumph parts dealer as the conical hub should be identical on both BSA and Triumph in 1971-2.
I am sitting here with the brake plate next to me, the shoes have quite a bit of meat on them and are fitted with the caps 37-4018. The shoes are actually stamped MCD2 37-4018, can't be original, can they ? The problem remains, too much adjustment required. The drum looks good with no real sign of excessive wear. I have googled 37-4018 which is listed as correct. I am considering ordering new Bonneville Conical Hub shoes with the modified caps ( 37-4037 ). I thought I would throw this open to the readers first, thanks.
I would just buy the modified pivot pads 37.4037 first.
I think that you'll find most of the slack disappears.
New shoes and modified pads arrived from SRM today, will let everyone know how it goes.
Fitted new shoes with modified Triumph pivot pads supplied by SRM ( £4.00 ). Could not get the brake plate back in the wheel. Tried with standard pads, still too much adjustment. I ground about just under 2 mm off the modified pads. Now have a very nice back brake, job done. Hope this helps someone else.