Re: KPack's 1954 Panama

Posted by DavidPackard on 2021/5/28 12:53:33
I was thinking of taking my ’48 to a shop to have the rear end worked on. I specifically asked the mechanic on how he dealt with the shims, and his remark was ‘What shims?’, at that point I decided to do the work at home. Be cautious in selecting ‘shops’ to work on a 70 – 80 year old design.

Remember you measured the bearing clearance with feeler gauges before you re-assembled everything, and you had an acceptable number. Was it the measurement process you think an error could have been made?

I’m still skeptical about a bearing making a squeaking noise, especially one that you know has a good amount of fresh grease. I was just looking at the cut-away drawing of the rear brake, wheel, and axle bearing lay-out. I was quite surprised how close the outer most oil scupper comes to the outer diameter of the hub. Assuming a bit of oversized bolt holes in the outer shield I could imagine a bit of rub.

I’ll second BigKev’s remark about being on the lookout for witness marks. Also before the disassembly try to set-up a pointer close to the lathe center in the end of the axle (cotter pin removed), and see if you can detect a difference in axle ‘wobble’ one side to another. This pointer could be nothing more than a wire coat hanger and a few cement blocks. Nothing fancy, just a qualitative comparison.

The bearing clearance can be verified with everything assembled. The trick is where the measurement ‘stuff’ attaches. Think about some angle stock ‘C’ clamped to the leaf spring, or a dial indicator attached to a sizable mass positioned near the brake drum. Again both wheels removed, a helper pulling on the other side, and you pushing and pulling your side while taking the measurements.

Ross’s comment about the edges of brake shoes touching the drum is right ‘on point’. There’s one brand of old cars that uses the same tapered axle design that runs into that situation often. For that car there are aftermarket sheet metal shims available that fit between the axle tapper and the hub that effectively pushes the drum out board. I would think a bit of a bend in the backing plate would push a shoe out board, and that’s not a lot of clearance to begin with.

I’ve lost track . . . Is the noise coming from the side that had the ‘drum wobble’?


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