C1 Brake Drums

[Christopher R.]

I'm trying to discern the difference in brake drums that fit C1s. For instance, Chevrolet distinguished fronts and rears, but it seems they are the same. They also seem to be the same for 63-65 rears. They are the common Chevrolet 11" by 2" drums. They were used on many Chevrolet (and probably GM) products as rear drums well into the 1970s. So, what the difference in all of them? Why the different part numbers?

I'm thinking of buying new AIMCO (a division of Dana) drums, p/n 8101, from my local Autozone for $45 each. That almost seems to good to be true. When was the last time you could buy something for a C1 locally at a reasonable price? So, naturally, I'm suspicious.

Part numbers for other manufacturers are as follows.

Wagner BD60001
Raybestos 2003
Bendix 140022
EIS D2003

[Duke W.]

Re: C1 Brake Drums

My '80 GMPD Corvette Parts catalog shows two 11x2 drums for all C1 front/rear and '63-'64 rear applications (exclusive of any of the "heavy duty' brake options). For base brakes the part number is 3985944. This part number would indicate late sixties issue, and this was probably due to the FMVSS requirement for the maximum diameter to be imbedded in the drum circa 1968.

For metallic brakes a different part number is called out - 3869537. These are from the same castings (various numbers) but have a finer surface finish. My replacement J-65 drums that I purchased in the late seventies appear to have been die stamped with the max diameter. I expect that they were very old parts that were pulled out of stock and stamped to comply with the new law. They arrived in brown boxes with a yellow GM logo that probably date back to the sixties. I figured the drums were as old as my car at that point and had been in a GM warehouse since about the time my SWC was built.

From what I can tell, all the 11x2 drums are essentially the same and should be interchangable. All the replacements you can find on the aftermarket are likely fine, so you can just buy on price, but don't be surprised if they say "Made in China".

Duke

[Dave Suesz]

Did I read that right???

Does the C1 use the same brake drum front and rear? Or was I reading it too fast?

[Christopher R.]

Re: Did I read that right???

Yup. C1 fronts and rears (non-metallic) are the same, although Chevy gave them different part numbers.

That's my question - why? Or, what am I missing? I was incredulous too.

[James F.]

I'm missing something???

Chris,
My front brake drums contain the wheel bearings races and five studs for the whee riml nuts. The rear durms have six holes, one big one and five that allow the five studs from the rear axle to poke through. All '53/s -'62's were this way to my knowledge. What's similar? Regards,

[Christopher R.]

Re: I'm missing something???

Look at the fronts again. The studs and bearings are on the hub from which the brake drum will separate.

[James F.]

Chris, You're right! NM *NM*

[Dave Suesz]

Well gahlly!

The front drums were probably supplied with the hubs at one time. I DID know the Corvair and Chevy II had the same brakes, except the 'Vair had the big ones on the back! Ahh, the simplicity of pre-computer designed cars!

[Duke W.]

Re: Well gahlly!

Like I said in my previous post, my circa 1980 GMPD Corvette Parts catalog shows the same part number (base brakes) for all C1 front and rear drums, and '63 to '64 rear drums. Metallic brakes call for a different number, but the only difference is the finer surface finish.

None of the above applies to any of the various "heavy duty" brake packages

Duke