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[ric]

In your latest photo, left and right movement/positioning of the cam correlates to vertical movement on the plate and up and down positioning is horizontal towards the center brake plate hole. Any paint removal or scuffing on the face of the center hole will also indicate whats been happening when the brakes are applied.
If anything err adjustment towards the side of caution so if you find the wheel locking solid when you gently apply the brake make sure its only happening whenever the wheel is spun backwards. The brakes are the most important things on the bike and need to work both efficiently and correctly and best left to an engineer or other expert.

Once everything is sorted you'll finally have a brake the designers intended. Then you'll only need to work out the correct order to do up the three nuts after moving the QD hub

[Chris [Stockport]]

Is there a thing about slightly chamfering the ends of the shoes so they don't grab by the ends, but it's the whole surface of the shoe that does the braking?

[ric]

Once you've got everything adjusted correctly and have the axle falling through the brake assembly, you can snug those bolts and their locknuts down and then recheck the axle is still completely free before fitting everything back together on the bike. They only need to be loosened off for readjustment whenever a new set of shoes are fitted. It does seem a good idea to leave them loose because the shoes will always self center every time the brake is applied IF they were never correctly centered in the first place but it can lead to catastophic consequences further down the line because this also allows the cam spindle to move horizontally as well. .

[Jamesy]

I am sure they brake cams or on a splined shaft and removing them you can then move them clock or anticlockwise.Clean the drum with brake cleaner,grease the cams,Emery the shoes.Do the front brake modified trunion and adjustment shown on this site and take it from there.

[another Allan]

Is the pivot for the cam spindle able to move because the fixing bolts are not tight?


If so, I think that this is a problem.


The pivot fixing bolts should be tight so that the pivot is fixed in position on the brake backplate.


With the wheel in the bike and the brake pivot fixing bolts slightly loose, apply the brake and hold it on hard (an assistant at this point can be useful.) This will centralise the brake pivot so that both shoes come into contact with the drum at the same time.


With the brake held on, tighten the brake pivot bolts.

[Lord-Toady]

I am getting a bit confused now shouldnt the brake cam bush just be central to hole and its bolts done up tight to stop it moving?

[ric]

Ignore the hole. it's there to provide adjustment not symmetry.
Look at the third photo; it's quite obvious the cam itself needs to move upwards so its end disc sits in the middle of the shoe plates. Unhook brake arm spring, Reassemble the shoes with the cam bush lock nuts loosened and the bolts slightly loose to provide resistance and push the cam into position. That's the horizontal position set.

Then put the brake plate carefully inside the drum, push the axle through and tighten into place on the swinging arm with the large nut.

Leave spring unhooked and apply very firm pressure to the brake pedal, this will move the cam bush vertically and centralise the shoes within the drum, keep the brake applied and turn the cam bush bolts anti clockwise from the outside using the ends of the bolts which have been machined specifically for this one purpose which will hold the bush lightly into position. Carefully disassemble everything checking the round disc on the end of the cam has remained centrally in its horizontal position, ignore the hole. If it has moved repeat. Then snug down the bolts from the inside using the hex heads and tighten their respective lock nuts on the outside. Refit shoes and position shoes inside drum, fit axle, apply brake by moving the brake arm with fingers. With the brake applied the axle should be free to drop or be gently pushed out if the cam bush has been tightened into place without being moved. Repeat until successful.
Refit brake arm spring and after fitting everything else into place and back on the bike but before tightening any of the nuts apply rear brake pedal firmly, tighten both wheel nuts up, forcefully rotate wheel forwards with brake still applied to sit the brake plate bolt down against the bottom of its slot and tighten its lock nut. Release brake.

The cam bush is now positioned correctly on both horizontal and vertical planes for that particular set of brake shoes. Repeat process in 40-50,000 miles time with next set of brake shoes.

[Lord-Toady]

Hi Ric, thats for that I understand what you are saying now, I should let the force of the brake shoes pushing against the rim find the correct position for that bush themselves. Do up the bolts from the outside and then take apart and do the bolts up properly.



That makes sense except that those bolts that hold the bushing in place they do not seem to have a provision for being done up from the outside on my bike. Infact one of the nuts looks badly rounded off. I think to set things up as you are suggesting I need to replace the bolts and the lock nuts?









I suppose i could tighten up those bolts tight enough so it still allows a little bit of movement from the inside then apply the brake hard so the bush is forced to shift postion with the bolts still tight enough to keep it where it ends up and then take apart again and torque them down hard. I suppose I can leave the bike on the jack in the garage until an order from hitchcocks comes in as it looks like it will be a wet weekend anyway.

[Lord-Toady]

These the the bolts that hold the cam bush down according to the parts catalogue:


PART No. 110282 - PIN, REAR BRAKE CAM BUSH, LONG

PART No. 110286 - PIN, REAR BRAKE CAM BUSH, SHORT


Held in place with these nuts:


PART No. 140369 - NUT, 1/4 X 26TPI, THIN


They just look like they have round ends on the bolts they dont have an end you can turn and do up by turning anti-clockwise, hmmm.

[ric]

New bolts are not absolutely necessary, as you mention tighten the bolts enough so the bush can be moved into position by the force of the brake pedal.