Rear Backing Plate Blues

Stinch

Stinch

Senior Member
I've got my rear rear backing plate for the brakes cleaned and primered. New bushings for the new brake camshaft have also been installed. The lever for the camshaft has been hot peened on and now the camshaft is hard to move for both the right and left side.

Figured no big deal, I'll grind the heads of the pins, drive them out and start over. Not so much. The pins will not move and frankly I've had it. My favorite local machinist closed up and I'm at the point where I'd rather just send it to someone who knows Model A's and what they are doing. Bratton's offers a backing plate service but in my case most of the work is done including the roller tracks. I just need the camshaft rotation sorted out. Any recommendations are appreciated.

Thanks
Rich
 
When bushings are installed a certain amount of distortion will usually occur. The bushings need to be reamed before the camshaft is installed. I'm surprised that you didn't notice the drag when you slipped the camshaft in place. Bratton offers a special reamer for this purpose part # 3101 price $67.35 . I can see where this is probably too expensive for a one time use. Before I could afford the reamer, I used a brake cylinder hone in the drill. I don't know what to do about the pins, maybe drill them out. Good luck.
 
It's been a couple of years since I put it all together but I seem to recall the camshaft turned okay. I probably peened it knowing it was binding but thought it would work itself okay. Seems I've dug myself a hole. It is likely binding on the dust seal ring but it isn't opening up very easy either. I spent a hour tonight turning the camshaft/arm by hand hoping it would seat but all I'll getting is a sore arm. I know if I try to drill out the pin I'll open up the hole in the arm. My machinists got the original pins out but now he has closed up shop otherwise I'd bring it back to him. Frustrated, I'm hoping to find someone who does this work and maybe I can get the brakes in the car this year.
 
How about putting the cam block between a couple of bricks and then give the arm/shaft a good "whallop" with a BFH (Big fat hammer - not usually fat)

You may compress the dust ring enough - or mash it into the shaft housing to allow the shaft to develop some free play?

Or try the "t'other" direction and beat on the cam block?

You should be able to take off the head of the rivet and then using a nearly fully size drift whack it out. Don't drill though - that's setting yourself up for failure.

Joe K
 
You don't need to drill the hole as big as the pin. If it's a 1/4"
pin drill a 3/16" hole and it will relieve the pressure on the pin.
 
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