The Stovebolt Site Forums The Shop Area Driveline 46 chevy 3/4 ton 8 lug brake drum thickness

I would like to have the front drums turned on an 8 lug 3/4 ton chevy pickup. From the inside of the drum measurements are 2 1/8" by 11 inches. They are huck-style brakes and shoes. It would be nice to keep the axle and new kingpins as conversion to disc brake kits are not available with the 8 lug rims.

Anyway, my question is, can anyone advise me based on the info provided here? The man who would do the work was not sure if they had been turned too much or not and suggested I find a 'really old' chevy mechanic who could advise me. I didn't tell him I know a bunch of 'really old' gear heads on the bolt. I'm pretty old myself but not a chevy mechanic!

thanks in advance,

Lane

Looks like 11" is the nominal size. Generally speaking, .030" over is the maximum machining, with .060" over as a discard measurement, provided they are not scored and the braking surfaces are fairly flat.

I would think that they are still good at .060 over. However, most sources quote that as the limit. If they are not out of round, I would not turn them.

Most 3/4 ton drums can go .090" oversize without problems, but don't take any more out than necessary to clean up the majority of the roughness. A couple of grooves in a drum with most of it smooth and round will not cause major problems. The old style riveted-on brake linings used to cause a couple of deep grooves where the rivets started contacting the drums without causing other problems. I've turned many drums mostly smooth while leaving a groove or two. No problems with those drums.
Jerry

thanks everyone ..... I think the man who was going to turn them for me was a little gun shy and didn't really know on this old truck what the limits were .....

Lane