rear brakes on an AA

Ken Arms

Ken Arms

Well-known member
Hi folks, im helping a friend with his rear brakes on his AA truck. It appears that the rear brake adjusters are stripped. I assume they are threaded so as you turn them in they would move the wedge in to expand the shoes out closer to the drum surface. they turn but dont seem to go in. Is this a common problem? I dont understand how they can get stripped in the first place! It looks like there is a cap that would need to be removed to get the adjuster out from the inside. could they be tapped and heily coiled or if its the threads on the adjuster it self are they available? Any help would be wonderful. Ken
 
It may be your adjusters are "at the limit of their adjustment." As in the shoes are worn to the point where the pointed end has passed both the bevel "Brake Adjusting Shaft" AND the threaded neck of the backing plate.

You can see what is up - tap the now loose adjuster thread and see if that "pops" the cap off the housing enclosure. Best to be done with your hub/brake drum removed. You may be able to push the adjustment wedge all the way "through" and have it left in your hand.

You don't say if this is the 28-29 version AA which has smaller shoes (narrower particularly on the 28s) or the 30-31 version which are larger in diameter and wider. Given your issue, its probable you have the earlier, lighter AA.

Rethreading may not be required. New shoes/drum-turn might be. And a new adjuster will probably help too.

I see only 30-31 adjusters in Snyders for AA truck. Nearly $60 each. The 28-29 AA may use the car adjuster. $12.50 ea.

Joe K
 
Thanks Joe, he calls it a 30 but the grill shell looks 28-29 to me. Shoes look new. drum is gigantic and it has separate e brake shoes. the adjuster looks like the same ones on my 34 car
 
The AA truck kept the 28/29 cab and sheet metal into June 1930 .The heavy brake drums indicate first half of 1930 . These trucks can have 30/31 headlamps .bayonet gas caps and 30/31 steering wheel .My April 30 has these features.

John in Fall weather Suffolk County England .
 
John Charlton is correct - after about October 1929 Ford changed the AA over to a Borg Warner design. You can confirm this if it has a 4 speed ******. In general the 30-31 components are a LOT beefier than earlier.

And not to say that nearly 100 years of use the original drums/shoes/components need renewal to compensate for wear.

I'm still thinking worn shoes. I would start with this. Go for a disassembly (not a small task in itself on the Model AA) and checking out the fit form and finish of the brakes. I can see measuring with calipers the ID of the drum, measuring the OD of the shoes, and getting an idea dimensionally of the "fits together" for function - or in your case likely not function.

I have done this on a Model A with a bungee cord around the brake shoes.

Most, even Henry Ford himself, don't appreciate that 2/3rds of the stopping power of any vehicle come in the front axle. The physical geometry of the center of weight is the cause where stopping itself tends to make the front axle "heavy" on the road and correspondingly "lighter" on the rear.

A condition which probably has caused someone to pay more attention service-wise to the front brakes than the rear. But not to say the rear is not subject to wear.

Or - you may find other issues in the tear down.

Joe K
 
well as it turns out the adjuster is not stripped. But turning it all the way in does not move the shoes enough to have any brake at all. the shoes appear to be relined. I have no idea if the drums were turned or not. The gentleman that restored the truck has passed so no info. If the brake adjustment followers were installed backwards that connect to each shoe could that be our issue or too short. Did the AA use longer ones than a car/pickup. Thanks for the info about cab design. There must be a ser # on the frame that would tell us the year. thanks Ken
 
According to Snyders the A-2042 "Brake Adjusting Shaft" ($6.25 ea) IS available.

However, the AA part (1932 Parts Price List) shows as "BB-2042"(formerly AA-2042) with an application year of 1928-1932. Not available at Snyders.

I'm pleased to learn there is a true part number difference - although Ford is not shy on simply "renaming" an identical part for the A car for use on the AA truck.

A better confirmation is found in the so called 1928-1947 "Green Book" (used by a post-war Ford company to service largely prewar Fords) where not only the part number(s) are retained but also a "sketch" of sort of the two parts. See page 30 lower left hand for a dimensional drawing. So yes, the two parts are "different."

Since the larger AA part is not available reproduced, you may be forced to "adapting" what you have by adding weld or even re-creating whole. The drawing above will be helpful.

Yes, I would get the "Green Book" if you don't have it. It's available on a CD (less than $30) or you can look around Ebay and find the soft-cover book at "varying" prices. Shop around under various names. Green Book, Chassis Parts & Accessories, Ford 1928-1947, etc.

Edit: Best price for a soft cover NEW reprint is $30 Plus $16 shipping. Older reprints exist for less money but include greasy thumbprints gratis.

Joe K
 
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wow Joe, great info.. I have a green bible but have never used it until now. shows dimensions on parts in question. Thanks so much Ken
 
We resolved the issue, turns out when we thought the adjustment was at the end of its travel it was not, it just turns much harder I think because the shoes get tight against the drum until they fall into the grooves . We got brakes now!
 
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