New brake drum availability?

[MSeriesRebuild]

I have never found good drums to warp easily but I don't live in the desert either. the NW is mild.

The key word here is "GOOD"; however there aren't any take-offs that fall into the "good" category.

[ZGjethro]

How would one measure their drums to see if they are in spec? Inner diameter? Wall thickness? How about out of round? Is there a way a guy can tell if drums are decent or not without going to a brake shop? I ask since there are none within an hours drive. I have at least one brake giving me a pedal pulse, and two spare drums in the garage. My truck barely pushes 45mph downhill at 8000', but the high revs stop me from pushing it. I will probably try new cylinders and shoes before I go to discs. Even before that I'd like to do a dual circuit master cylinder for a little redundancy.

[Kaegi]

a drum mic is the best way. or if you have a mic that will measure that large a hole.

[ZGjethro]

That would be a big negative. Digital calipers only, I could easily buy a micrometer, but I'd want to get one for general usage. Can you tell anything about how true they are by spinning thin on the axle and checking outer surface true?

[Kaegi]

cant be judged at all by the outer surface. castings are not precise enough for that. in my experience the warpage has rarely been what makes them bad. more often they have just been machined too many times.

[Cal_Gary]

Well, based on all the guidance offered, I suppose I've gotten lucky since I had my drums turned last fall. I now have plenty of pedal, no pulsing (indicative of out-of-round drums) and the truck stops straight and true without the brakes fading. Since I'll be putting few miles on it versus thousands per year I feel the brake overhaul more than met my expectations but recognize that it might not for those who use their trucks heavily with a lot of miles annually.
Just my experience for what its worth, knowing that Bert and others are planning a brake job in the near future.
Gary

[Elwood]

That would be a big negative. Digital calipers only, I could easily buy a micrometer, but I'd want to get one for general usage. Can you tell anything about how true they are by spinning thin on the axle and checking outer surface true?

Used analog drum brake micrometers are not that expensive. The digital drum brake ones are more expensive of course, but have an advantage (other than the ease of use and precision) in that they can often be set to take the ID of the drum at different depths. If the drum is bell mouthed, a traditional analog drum brake mic will not show it, as the mic measures at only one depth, usually close to the outer edge.

[Elwood]

No one here has yet mentioned using a brake shoe truing machine, such as the old Barrett Brake Doktor. Any reason why that method wouldn't work on an M37's Lockheed brakes? The old Ford guys seem to think they're a great tool.

[Kaegi]

No one here has yet mentioned using a brake shoe truing machine, such as the old Barrett Brake Doktor. Any reason why that method wouldn't work on an M37's Lockheed brakes? The old Ford guys seem to think they're a great tool.

I have a shoe arcing machine and arc all my shoes before installation. it really makes a difference in Lockheed brakes. the brake relining shops will do it for free if you have your shoes relined with them and give them your drum measurements. Or if you have shoes you can take your drums and shoes to a reliner and they will do it for a small fee. but it wont help oversized drums get smaller. ;/)

[MSeriesRebuild]

Arcing relined shoes is a must with turned drums as the original arc will no longer fit the inner drum radius. We have one on our relining machine; however there is no use to think this will make a hill of beans worth of difference in a drum that is cut too thin.