I just got a '62 Hawk. The brakes are being re-built. The factory service manual says the limit to cut drums is .060. The parts place in Redwood City says I'll be OK up to .090 over. A trusted friend says that .090 is crazy risky and minimally I'll have to "crown" the linings to go that much over-sized. Anybody got an opinion?
The factory service manuals are a very good reference for this sort of thing. The people who wrote them pretty much knew their product. The guy at the auto parts store, maybe not so much. Of course, many people have machined drums oversize beyond the recommended limits and, predictably, will tell how that worked out just fine. Because it didn't thunder and lightning, the ground didn't open beneath thier feet, they are convinced they were no negative consequences. I'd check with Studebaker International and see what new drums cost and go from there. If you do decide to machine them larger than recommended, I suggest you check just how closely the lining on the new shoes matches the contour of the drums after machining. You may also find some really old automotive/truck machine shop who still has a shoe re-arcing grinder. Or, very careful use of a disc/belt sander (machine mounted on a stand, not a handheld variety) could improve a poor fit. Ray
You might ask over on the forum of the Studebaker Driver's Club or Racing Studebakers! Lotsa info and helpful folks in both places.
An easy visual for most drums is they have a small 45 degree bevel on the outside edge of the drum. If there's no bevel left, the drum probably won't turn within spec. Like Sunbeam said, the maximum diameter of the drum is probably cast into it.
The Guys at the Studebaker place in redwood City know their stuff. Look to The SDC for info- they are a great group of guys, and there are a lot of resources in the area for parts, if your drums are bad.
I had my front drums (55-later) turned out at .090 Let me tell you they didn't stop all that well even with new shoes, hardware kit, and wheel cylinders. Also I didn't get very long service out of all those new parts, before the wheel cylinders started leaking. This was before replacement drums were available on the market, and I didn't have much choice. So no, I would not recommend turning out that far. Try Studebaker International... http://www.studebaker-intl.com/2012_website_catalog.pdf
Most front drums had a limit of .060 over, rears were a little more lenient at .090 over. Some aftermarket fronts allowed for .090, I'd err on the side of safety and better braking and get new drums if I had any doubts. Bob
I will leave it to you to verify but I think the legal limit in California is .060 unless otherwise marked (some drums are marked with a max diameter). You might ask this question at a good brake shop. If I am correct on the legal limit you have a liability issue, both moral and legal. Charlie Stephens
Thanks for the replies. As is happens the drums were not as bad as suspected. The machine shop was able to clean them up and the barkes work quite well now. The front drums cannot be cut again, the rears have one more rebuild left on them.
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