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Brake Drums

Posted: October 24th, 2019, 10:08 am
by David R.
What are maximum turning diameters for AA drums? Are replacements available?

Re: Brake Drums

Posted: October 24th, 2019, 11:16 am
by Chris Haynes
I picked up a good used set of cast iron '32 drums for mine.

Re: Brake Drums

Posted: October 27th, 2019, 7:30 pm
by tiredtruckrestorer
The original AA pressed steel drums are hard to turn on modern drum turning equipment. Back in the day, pressed steel drums were ground true on brake drum grinding machines. I found an old truck drum grinding machine and did a few drums, but when I ran out of grinding stones I haven't been able to find any replacement stones for the machine. Like Chris said, BB cast drums will fit, but I also found some cast drums with AA part numbers on. Don't know if they were late '31 cast drums or later replacement ones. Never got to the archives to look up the part numbers to see when they were actually made available.

Keith

Re: Brake Drums

Posted: October 28th, 2019, 4:18 am
by David R.
Thanks Keith. Does any one know what minimum wall thickness should be, or maximum turned diameter is? Why are they hard to turn? Do they chatter?
The brake linings on this one axle were hardly worn at all, but thoroughly grease soaked.

Re: Brake Drums

Posted: October 28th, 2019, 3:56 pm
by KimVanOrder
I thought the Min. wall thickness was ref. in the Red Model a ford mechanics hand book.. I'd look it up , but it is in the barn. Google it?

Re: Brake Drums

Posted: October 28th, 2019, 4:05 pm
by KimVanOrder
just found this...

Snyder's catalog indicates .130 is the minimum. Some of the "How to Restore Your Model A" books indicate .120.

Re: Brake Drums

Posted: October 28th, 2019, 6:53 pm
by Bob C
Those numbers are for Model A's I think AA's would be thicker.

Bob

Re: Brake Drums

Posted: October 29th, 2019, 4:02 pm
by KimVanOrder
My AA is a "28, same parts as an A. Newer may have different parts.. When in doubt, Thicker is better. Get new or drive slow.. :lol:

Re: Brake Drums

Posted: October 29th, 2019, 7:09 pm
by David R.
I bought spare front and rear axles when the opportunity came along. I worked on disassembling spare front axle this evening. Brake drums just do measure 14” so I should be good there? Linings hardly worn; but grease soaked. I believe the grease came from the Loray tar pits.

Re: Brake Drums

Posted: November 1st, 2019, 2:38 pm
by Chris Haynes
David R. wrote:
October 29th, 2019, 7:09 pm
Linings hardly worn; but grease soaked. I believe the grease came from the Loray tar pits.
Would that be The LaBrea Tar Pits? I have never heard of Loray Tar Pit. Neither has Google. :-)

Re: Brake Drums

Posted: November 2nd, 2019, 4:52 am
by David R.
Yes, thank you and excuse my ignorance. The grease was very sticky and tar like.