'47 Tudor brake issue

[don-wi]

I did a complete brake job a while back on my car. The brakes are OK but not what I feel as 100%. I installed new wheel cylinders, brake shoes, master cylinder. The drums measure out at 3/32" oversize on the left rear and 1/16" oversize on the right rear. I have pressure bled the brakes a few times so I'm sure that I don't have air in the system, I also adjust them to a light drag before I bleed them. When I pulled the rear drums the other day I see that my shoes are making poor contact. Just looking for some opinions but I think I am going to need to replace the drums. Thanks for taking a look.

[mfagan]

You might consider getting someone arc grind the shoes to
fit the drums.

[1931 flamingo]

If the drums are that much oversize you probably need to replace them, turn them and then have the shoes arced to the new drums for full contact.
Paul in CT

[DICK SPADARO]

You have pretty much trashed the drums, 3/32 over is around .090 large and 1/16 over is .062 over, these drums max out at around .080 over. Unless you have over thick brake material you do not have equal radius of the shoes and the drums so it produces a spotty braking surface until they wear in. This can be addressed if you find someone with a brake shoe arch sander to marry the oversize radius.

[Roger W Gerow]

My local machinist did the following for the brakes on my '40 Ford. He turned the drums, measured things out, then used thicker brake lining. Turned out great.

[don-wi]

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Thanks for the input. I have the drums that have the hub on the outside of the drum. How can I determine if I have cast or steel drums? I have been told that turning steel drums is very difficult. I am going to have my drums machined to .100 oversize, have the shoes relined with thicker material and then have them arched to fit the drum.
Thanks Don

[19Fordy]

Drums on a 47 Ford are cast. You are endangering your life by machining those drums
to .100 over as the drums are made to absorb heat generated by the brake shoes. Brake fade will be the result. If you have an accident, your insurance company may just check your drums, especially since you posted your intentions on the internet. Go to http://www.mtcarproducts.com/ and buy new components. Your life and the lives of others on the road are well worth it and you'll be happier knowing your brakes are in good condition.

[Charlie Stephens]

Originally Posted by 19Fordy

Drums on a 47 Ford are cast. You are endangering your life by machining those drums
to .100 over as the drums are made to absorb heat generated by the brake shoes. Brake fade will be the result. If you have an accident, your insurance company may just check your drums, especially since you posted your intentions on the internet. Go to http://www.mtcarproducts.com/ and buy new components. Your life and the lives of others on the road are well worth it and you'll be happier knowing your brakes are in good condition.

One minor comment, it won't be don-wi's insurance company checking the brakes it will be the lawyer for the person or persons he hit. Another thing it will be hard to find a machine shop that will turn the drums that far knowing that they might be liable in case of an accident. It is none of my business what color he paints the car but cutting corners on brakes affects us all.

Charlie Stephens

[V8COOPMAN]

For don-wi's reference, and what nobody has specifically mentioned yet, it is UN-LAWFUL to turn those particular drums more than 0.060", which equates to a max diameter of 12.060". DD

[19Fordy]

Excellent point! Remember that song, "I Fought the Law and the Law won."

[Charlie Stephens]

Originally Posted by V8COOPMAN

For don-wi's reference, and what nobody has specifically mentioned yet, it is UN-LAWFUL to turn those particular drums more than 0.060", which equates to a max diameter of 12.060". DD

I also had the understanding that it was unlawful to turn more than 12.060 unless otherwise indicated on the drum but have been unable to find the specific law. Do you have a reference (even in your state)?

Charlie Stephens

[V8COOPMAN]

Originally Posted by Charlie Stephens

I also had the understanding that it was unlawful to turn more than 12.060 unless otherwise indicated on the drum but have been unable to find the specific law. Do you have a reference (even in your state)?

Charlie Stephens

Charlie S.....I have NO specific reference handy, but have been given to understand that the .060" was a FEDERAL kind of mandate to be adhered-to UNLESS the drum had a different, acceptable dimension demonstrated upon itself by the manufacturer. I know I've seen Buicks and even the current MT drums with .090" on them. If Richard Lacy is lurking, I'd bet he could shed more light. DD

[19Fordy]

The DOT does have brake drum rules for commercial carriers, but the following seems to apply for other cars and trucks as specified by each state.
WARNING: DO NOT TURN OR WEAR A BRAKE DRUM OR ROTOR BEYOND THE MAXIMUM
DIAMETER OR MINIMUM THICKNESS STAMPED OR CAST ON THE BRAKE DRUM OR ROTOR.
The maximum diameter or discard diameter is the maximum diameter to which the brake drum may be turned or worn, and still be usable. If any portion of the brake surface exceeds the maximum diameter it must be discarded. The maximum diameter cast into the back plate portions of the brake drum supersedes all other specifications.

Here's what Ohio Law states. It's quite specific.
4513.202 Brake lining, brake lining material, or brake lining assemblies standards.
(A) No brake lining, brake lining material, or brake lining assemblies for use as repair and replacement parts in motor vehicles shall be sold in this state if these items do not meet or exceed the minimum standard of specifications established by the society of automotive engineers and the standard of specifications established in 49 C.F.R. 571.105 , as amended, and 49 C.F.R. 571.135 , as amended.

(B) All manufacturers or distributors of brake lining, brake lining material, or brake lining assemblies selling these items for use as repair and replacement parts in motor vehicles shall state that the items meet or exceed the applicable minimum standard of specifications.

(C) Whoever violates this section shall be punished as provided in section 4513.99 of the Revised Code.

(D) As used in this section, "minimum standard of specifications" means a minimum standard for brake system or brake component performance that meets the need for motor vehicle safety and complies with the applicable SAE standards and recommended practices, and the federal motor vehicle safety standards that cover the same aspect of performance for any brake lining, brake lining material, or brake lining assemblies.

Effective Date: 01-01-2004 Here's the MT drum spec as mentioned earlier.

[don-wi]

I was told by a parts supplier that the drums could be turned .100 and then have shoes arched to fit the drums. I'm not interested in turning my car into a ticking time bomb. I'm going on the hunt for a new set of drums.

[19Fordy]

Good move. I would not trust the .100 measurement suggested by " a parts supplier".
Just doesn't make sense.