The Ford Barn

AL in NY · 11-02-2018, 06:20 PM

I have been helping a club member with a brake problem on his 30 Coupe. When we got around to miking the brake drums, we were shocked on how thin they were. All the drum were steel(not cast iron). The front miked out around .105" and the rears were both about .060". The low end of the spec is .120". I don't know how he was able to get his coupe to stop at all. VERY UNSAFE. We are now in the middle of doing a complete brake job with 4 new hubs with case iron drums.

Synchro909 · 11-02-2018, 06:31 PM

He'll have to peel his face off the windscreen next time he uses his brakes!

BRENT in 10-uh-C · 11-03-2018, 06:24 AM

Al, be sure to check the rear axle housing races for being worn on the bottom due to lack of grease during its lifetime. Also, check the dry-fit of the brake drum bearing races and the diameter. The easiest method for checking the axle housing aces is to measure the OD of the race in the 3 o'clock to the 9 o'clock position, and then at the 12 to 6 position and compare the two readings. Anything more than about 0.010" is cause for concern because the hardening of the race area is only about 0.010" deep, and the wear in the hub and housing moves the drum out of the centerline of the brake shoes.

12secvx · 11-03-2018, 11:00 AM

What is the spec for cast drums? I have a set of 35 drums I turn and they are around 12.14” and .100 thick. I know thin. But I still might try them and keep my eye on them as they are hard to find.

Bob Bidonde · 11-03-2018, 12:23 PM

When new, the OEM drums had a 0.140" wall thickness. Allowing for a total of 0.030" depth of cuts in their lifespan, a reasonable minimum would 0.110" remaining wall thickness.

hazelhoff · 11-03-2018, 01:30 PM

Sponsored Links (Register now to hide all advertisements)

Maybe a 'farmer' solution, but ... Years ago I decided to buy a peace of steel tube (big one) almost matching the inner diameter of the front brake drum.
Had a ring turned on a large lathe. To just fit the plate steel drum. Before drilled 4 holes through the brake drum. Then pressed the ring in. Welded the four holes. Turned the assembly on th e big lathe to finish the new inside diameter.
This way you keep the appearance of the steel drum, which is much more better than the cast drums. The latter having sharp edges you don't want !

fredski53 · 11-04-2018, 03:25 AM

What's a "windscreen."

Tom Wesenberg · 11-04-2018, 05:46 AM

Quote:

Originally Posted by fredski53

What's a "windscreen."

Windshield

11-02-2018, 06:20 PM	#1
AL in NY Senior Member Join Date: May 2010 Location: Southern Upstate New York Posts: 1,160	Have you "miked" your brake drum lately I have been helping a club member with a brake problem on his 30 Coupe. When we got around to miking the brake drums, we were shocked on how thin they were. All the drum were steel(not cast iron). The front miked out around .105" and the rears were both about .060". The low end of the spec is .120". I don't know how he was able to get his coupe to stop at all. VERY UNSAFE. We are now in the middle of doing a complete brake job with 4 new hubs with case iron drums. __________________ AL in NY

11-02-2018, 06:31 PM	#2
Synchro909 Senior Member Join Date: Jun 2014 Location: Melbourne, Australia Posts: 7,495	Re: Have you "miked" your brake drum lately He'll have to peel his face off the windscreen next time he uses his brakes! __________________ I'm part of the only ever generation with an analogue childhood and a digital adulthood.

11-03-2018, 06:24 AM	#3
BRENT in 10-uh-C Senior Member Join Date: May 2010 Location: Eastern Tennessee Posts: 11,508	Re: Have you "miked" your brake drum lately Al, be sure to check the rear axle housing races for being worn on the bottom due to lack of grease during its lifetime. Also, check the dry-fit of the brake drum bearing races and the diameter. The easiest method for checking the axle housing aces is to measure the OD of the race in the 3 o'clock to the 9 o'clock position, and then at the 12 to 6 position and compare the two readings. Anything more than about 0.010" is cause for concern because the hardening of the race area is only about 0.010" deep, and the wear in the hub and housing moves the drum out of the centerline of the brake shoes. __________________ . BRENT in 10-uh-C . www.model-a-ford.com ...(...Finally Updated!! ) .

11-03-2018, 11:00 AM	#4
12secvx Member Join Date: Nov 2015 Posts: 91	Re: Have you "miked" your brake drum lately What is the spec for cast drums? I have a set of 35 drums I turn and they are around 12.14” and .100 thick. I know thin. But I still might try them and keep my eye on them as they are hard to find.

11-03-2018, 12:23 PM	#5
Bob Bidonde Senior Member Join Date: May 2010 Location: Long Island, NY Posts: 3,462	Re: Have you "miked" your brake drum lately When new, the OEM drums had a 0.140" wall thickness. Allowing for a total of 0.030" depth of cuts in their lifespan, a reasonable minimum would 0.110" remaining wall thickness. __________________ Bob Bidonde

11-03-2018, 01:30 PM	#6
hazelhoff Senior Member Join Date: Dec 2013 Location: The Netherlands Posts: 387	Re: Have you "miked" your brake drum lately Sponsored Links (Register now to hide all advertisements) Maybe a 'farmer' solution, but ... Years ago I decided to buy a peace of steel tube (big one) almost matching the inner diameter of the front brake drum. Had a ring turned on a large lathe. To just fit the plate steel drum. Before drilled 4 holes through the brake drum. Then pressed the ring in. Welded the four holes. Turned the assembly on th e big lathe to finish the new inside diameter. This way you keep the appearance of the steel drum, which is much more better than the cast drums. The latter having sharp edges you don't want !

11-04-2018, 03:25 AM	#7
fredski53 Senior Member Join Date: Jul 2013 Location: La Porte, IN Posts: 143	Re: Have you "miked" your brake drum lately What's a "windscreen."

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