NORS Asbestos Brake Shoes

[Rotary FP46]

I have several sets - new in boxes.

Encountering a few odd characteristics that I wasn't expecting.

Could use guidance from the few of you who worked with the things when they were still commonplace.

Going through the crates right now. Will add questions as they come up.


SET No. 1:

Take these for example. (In a way, Sets No. 2 and 3 are a bit stranger.)
Packaging indicates that the brand is Friction Materials, Inc. out of Baltimore, MD.
The edge of each of the linings reads "Bendix MN FF".
Part number on the outer box is 241R.

I had never heard of FM Inc. Definitely don't have a catalog for those folks.

Questions:

- Is 241R an FMSI number, or were those strictly 4-character and purely numerical strings?

- When I attempt to cross "241R" over at Rock Auto's part number lookup, the only brake shoe that pops up in the results is a Raybestos "241PG". It doesn't have exactly the same shape as what's here, but...maybe it's an updated design? What significance do the suffixes in these part numbers carry?

- What is "MN FF" a reference to? Can this be used to determine the application?

- Was FM Inc. just a rebrand of Bendix, or did Bendix just make the lining for FM to assemble?

SETS No. 2 and 3:

Bendix in a Bendix box. Someone wrote "Corvair" on the box, but the application will have to be confirmed.

Odd thing here is that the primaries and secondaries are different colors.

Questions:

What are the secondaries made of?

Why was this done?

What is Chevrolet (or even GM) Part No. 312595?
My 1976 and 1962 Corvair parts manuals come up empty.
GMPartsWiki comes up with 312595 as a Spicer number (equivalent to GM Part No. 660539), which is a clamp of some sort.

[Frank DuVal]

The brakes on a Corvair, and most GMs of that era, are duo-servo acting. This means the primary shoe hits the drum first, kicking the assembly of the primary and secondary shoe "rearward, i.e. forces the secondary shoe into the drum, acting as a brake force booster effect. Part if this effect is from different friction compounds in the primary and secondary shoes. So it is normal for the friction compound part numbers to be different primary to secondary. These are the numbers on the side of the friction. The color can also be different.

241 is the 2.5" wide 9 1/2" diameter GM shoe. It is typically paired with the 242 2" wide 9 1/2" diameter shoe.

Now, Corvair late model brakes are "backwards" from Chevy II (Nova to most people) and Camaro models, i.e. wider shoes on Corvair are on rear. So 241 is the rear LM shoe.

There is another series of shoe, where 245 and 246 are the pair, and there is a slight difference in the steel. 245 being 2" wide and 2.5" wide for the 246. These are interchangeable on Corvairs (241/246 and 242/245).

I do not know what the R suffix is for, but like PG is a Raybestos suffix on the interchange 241 number to indicate quality/friction range.

Friction Materials is probably a local re-liner of shoes, like we had Brake Supply company in Richmond. I used to exchange shoes right there. And get industrial crane shoes relined.... They buy friction from the major suppliers, like Bendix.

So the last question:

The FMSI number on that Bendix box is 111. That is the first brake shoe for a Corvair, 1960. Notice the added thickness at the anchor point. Manual adjusters and a different anchor pin than 64 models. (I forgot where the change happened, but 189 shoes fit 60 to 64 just fine, so only 189 now available).