CB77 brake cams

[Kaiser Karl]

Hi folks
I've posted this in "transmission" due toat senior moment! G has already replied however I'm re-posting in the correct section.
Relined shoes in both brakes; the rear has the cable fully adjusted and the brake is poor. The front isn't as bad but not as good as it was with the worn linings! The levers are lined up with the dots. I've just seen that the cams for front and rear are different part numbers and I didn't separate them after disassembly. I've just taken the rear brake out again as G asked if I had adjusted the linkage so I'm give it a look to check the operation of the shoes.
Anyone experienced similar before taking the front wheel out to check the difference in the cams?
Thank s for any suggestions especially about the cams being different.

[AlanW]

Hi, Could you post your location please?
From memory the rear cam spindle is longer than the front = different part and number, if you put the front ones in the rear the splines won't come all the way through the brake arm and you can't get the bolt through. I think G is on the right track with adjustment.
Cheers Al.

[Kaiser Karl]

Good afternoon Alan
I live near Oxford/Cotswolds.
I took the brake plate off again to re-check G's suggestion. Both shoes expand at the same time E and distance! The snag is even with the cable fully adjusted to max the wheel doesn't even show resistance so can't check it when installed. I appreciate the info re the cams; it's the length that differs so they are correct. I've owned this bike for about 25 years and never experienced this before. The shoes are the same ones just relined and the cable is new a d there's no difference with the old cable fitted and the dots are in line. It must be my doing but I can't figure out what!
I recently fitted a clutch to my Beemer R100RS and put the diaphragm in back to front but that was easily diagnosed and quickly sorted. Grey hair I think😚

[G-Man]

How about some pictures? You're suggesting that the linings are not touching the drum so you have done something wrong. Without pictures it is difficult to see what.

The setting drill usually involves getting both levers pressing on the linings so that they are touching the drum with the linkage slack. You can then just take out the slack and tighten the locknut.

G

Good afternoon Alan
I live near Oxford/Cotswolds.
I took the brake plate off again to re-check G's suggestion. Both shoes expand at the same time E and distance! The snag is even with the cable fully adjusted to max the wheel doesn't even show resistance so can't check it when installed. I appreciate the info re the cams; it's the length that differs so they are correct. I've owned this bike for about 25 years and never experienced this before. The shoes are the same ones just relined and the cable is new a d there's no difference with the old cable fitted and the dots are in line. It must be my doing but I can't figure out what!
I recently fitted a clutch to my Beemer R100RS and put the diaphragm in back to front but that was easily diagnosed and quickly sorted. Grey hair I think😚

[AlanW]

Just a thought, is the new cable the same as the old one, could the new inner be longer?
Al.

[DJM]

From memory the original linings on these bikes were 5mm thick.

I understand that many re-line companies now only use 4mm stock material, if yours have been done that way your new shoes are probably already smaller than the old ones were, certainly worth checking out.

Even if your new linings are the correct thickness they will take a while to bed in and work properly but, if you've got he right shoes and put them together correctly you should have plenty of came adjustment available, if you're using up most of the adjustment from the off your linings are probably too thin.

Best way by far is to have the shoes relined with oversize material and then have them machined to fit the drums, which of course might themselves be worn oversize after fifty years.

Getting them done this way is a little more trouble and expensive but you might be amazed how good the brakes will be, well worth the money.

There are a few specialist companies who will check and re-skim the drums too if necessary obviously before machining the shoes which will give you brakes far better than even a new bike had.

[G-Man]

DJM

I use a company near you who put thick linings on which necessitates machining the new linings to fit.




I was able to skim the drum and still needed to machine the linings for my CB72 build.



G