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Brass Era Brake Drum Problem/Seeking Help..


AVS619

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Greetings,

I have a 1909 Regal Model 30 Touring that my wife and I tour as much as we can but recently a jerking motion has developed in the application of the brakes. It appears that the left rear brake drum may have warped sligtly after a long down hill almost panic braking of the car (I was not the driver of it at the time). The drum appears to be a bit oval shapped now by about 50,000 of an inch (I did not do the measurement). Has anyone ever had a similar problem? Since I am not a machinist and have no tools for anything remotely like this, is there someone who could true the drum, any professionals or even a fellow hobbyist? Is it possible to use the good brake drum as a pattern and have a new one or two cast, and if so, where could this be done? Just to ask, does anyone else own a Regal that may have a spare brake drum sitting around? Anyway, we have signed up for a number of tours this year and need to find a way to solve this before Spring arrives. Please email me at edfors@charter.net. I can send email photos of the drum and brake mechanism if one wishes. Joyce and I will greatly appreciate any and all help. Thank you. Tom.

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Guest Rustybits

Tom,

I would be surprised if many brake drums are any better or that the slight warp is the problem. To check this swap the back wheels (complete with drums)and try it again.

Oil on the brake linings is a possible cause and I would also look for looseness in some of the rear axle mounting gear. If my memory is correct that car has trackrods from diff to chassis to prevent rear axle steering.

Also check the internal braking mechanism for problems.

Hope this helps,

Stuart (Australia)

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  • 4 months later...

I am too far away to help you, but I can tell you from experience exactly what to do. I have rebuilt a lot of brake drums over the years. I do not look for this work because building up the inside surface of drums reflects a lot of heat onto the wire feed metal spray gun, and the hand that controls it. In brief the process involves:

1) make mounting plates to machine the drums accurately on the lathe.

2) thoroughly degrese/clean.

3) Machine worn surface in coarse thread form

4) grit blast with fairly coarse aluminium oxide grit to further etch the surfac for bonding.

5)Do not touch the surface to be sprayed.

6)Carefully coat areas adjacent where build-up is not desired with Metco antibond.

7) Preheat slightly with metal spray gun to drive off any moisture.

8) Spray a bond coat of Metco 405 nickel aluminide, which alloys as it strikes the surface of the job, with exotherm which virtually creates a metallurgical bond.

9)Build up surface as required with Metco Spraysteel LS. This is a machineable work-hardening carbon steel with considerable Molybdenum content.

10) Seal pores of the coating with Metco air-hardening phenolic sealer.

11) Machine to size with a tungsten Carbide tool, at slowest possible speed; taking care to avoid vibration and tool chatter. About a month ago I rebuilt the brake drums of Bob Schuhkraft's 1914 Chev. I machined the inside first with a length of 2"x 1/4" leather strapheld tight around the outside with a "hoseclamp." Then I machined the outside while holding a short wearpiece of the same leather inside the drum as it rotated, inside where the tool was cutting outside.

A drum like this will last indefinitely. The friction characteristics are similar to SG cast iron, and the job is compatible with modern brake lining materials. Drums expand less in use because there is more mterial to absorb the heat. It is sensible practice to cut a series of diagonal grooves in the ling, a couple of inches apart, angled so the drum with expell any rain and brake debris towards the inside so your wheels do not get as dirty.

(Napier used diagonal grooves in their cat iron brake drums in steel drums as early as 1911.)

One of my customers used new cast iron linings in the badly worn brake shoes of a brass car, and never told me till years later. They are still working well, and the drums not worn after about 25 years.

Ivan Saxton

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