Brake Drum

[Sam D.]

I have a part # on the brake drum that reads 3869538, I have a 64 corvette. is this the original brake drum and is so what the dimensions on this drum. Do thye make different size for this year? it is a J65 car with the original shoe still on the car. Up-Date Here are the #'s off the drums Front: 3828671 W7 of to the side Back: 3869538 W-7X of to the side


Thanks,

Sam

[Harry S.]

Re: Brake Drum

Sam, the number on the drum is the casting number, the part number is something different.

Anyway, best I can recall, I assume you have standard brakes, the front drum for a 63/64 has a casting number of 3828671 and the rear drum is 3828688.

Harry

[Sam D.]

Re: Brake Drum

Forgot to mention it is a j65 car with the original delco shoes still on the car. Are these different durms then the standard non j65 cars. here are the #'s off the drums Front: 3828671 W7 of to the side Back: 3869538 W-7X of to the side

Sam

[Harry S.]

Re: Brake Drum

This is going to sound weird but the J65 and the J50 drums were the same casting number. BUT, the J65 drums were thicker in one of the dimensions, can't remember which one.

Saying that, I'm sure someone else will jump-in.

Harry

[Duke W.]

Re: Brake Drum

Sam - Do you have and 1963 Corvette Shop Manual and 1964 Supplement?

If not, you need to procure these documents and study them?

In a previous thread I discussed some differences between the J-65 and base drums, which are very subtle.

One thing you need to do is measure the thickness of the front drum web with a mic or caliper and report it to the TDB.

Your post is confusing. Are you saying the drum has TWO numbers?

Please report each drum seven digit number (or numbers if there is more than one) and whether or not each is cast in or die stamped, and whether or not the drums have a "maximum diameter..." and whether this data is cast in or die stamped.

If you can take and post photos - that would be great!

There are several of us who have been researching C2 drums, both base brakes and J-65. In addition to what help we can provide you, you may be able to help us resolve some ambiguities in the present knowledge base.

You say your car has J-65 brakes, so they may be original. How many miles are on the odometer, and do you have good reason to believe the total mileage is correct, keeping in mind that it could have rolled over 100K miles and it was common for the odometer drive gear to break on C2s without being immediately repaired, which is some cases caused tens of thousands of miles to be accumulated before the gear was replaced and the odo began working again.

Harry - J50 was the power brake option, and it was available with both base and J-65 brakes, so there is no such thing as "J-50 drums". Drums are either base, J-65, or J-56, which is the HD brake package that was unbundled from the '63 Z-06 package.

Duke

[Harry S.]

Re: Brake Drum

Duke, using J50 was my poor and awkward way of saying non-metallic.

But, I am becoming a believer that the non-metalic and the metallic drum has the same casting number. The difference is the thickness and that one has an F stamped into the drum face and one has an X stamp.

Harry

[Bob J.]

Re: Brake Drum

I have a part # on the brake drum that reads 3869538, I have a 64 corvette. is this the original brake drum and is so what the dimensions on this drum. Do thye make different size for this year? it is a J65 car with the original shoe still on the car. Up-Date Here are the #'s off the drums Front: 3828671 W7 of to the side Back: 3869538 W-7X of to the side


Thanks,

Sam

Sam,
3869538 isn't the original drum from your car.
On the 3828671 drum is there a stamped letter on the face, usually where the wheel studs go through? Bob

[Sam D.]

Re: Brake Drum

I pulled all the drums here are the #'s off it: Pass. Rear: 3828688 W5 Driver Rear: 3869538 W-7X Pass front: 3828671 W7 Driver Front: 3828671 W1

Sam

[Harry S.]

Re: Brake Drum

Sam, it may be hard to see on your drum but as RJ asked, do you have an X or another letter stamped into your drum?.....Harry

As a reference point...

[Sam D.]

Re: Brake Drum

Hi Harry, there is an X stamped into both fronts same spots as your picture. On the rears, nothing in that area but along the rim there are WD after the cast # and a W-7X on the other rear.

Sam

[Harry S.]

Re: Brake Drum

I think the X is for Matalic and the F is for non-Metalic brakes.

Let's see who chines in!

Harry

[Joe L.]

Re: Brake Drum

I have a part # on the brake drum that reads 3869538, I have a 64 corvette. is this the original brake drum and is so what the dimensions on this drum. Do thye make different size for this year? it is a J65 car with the original shoe still on the car. Up-Date Here are the #'s off the drums Front: 3828671 W7 of to the side Back: 3869538 W-7X of to the side


Thanks,

Sam

Sam-----


GM #3869538 didn't exist as a released part at the time your car was built. So, it could not be original to the car. I would say it "came along" about 1965. However, that's not to say that it's not a 100% functional replacement for the original. As far as apparent configuration goes, it may well differ only in casting number. I don't think these casting numbers are judged, anyway, since they could not be seen with the wheels installed on the car.