Old GM Brake Drums

[Rotary FP46]

Corvair brake drums. Part numbers:

3841177
3841198
and
3850106


Not showing up in any of the parts catalogs, on GMPartsWiki, or at Clark's.

Are brake drums like radio parts in that they have their own special catalog?

I'm more or less reasonably sure that the first two numbers apply to LM cars, and that the third number is something small and early, but have no confirmation.

[vairmech]

Show a picture with a tape measure somewhere.

[isucorvair]

Per the internet

"rear brake drums GM #3841177
(WILL FIT 1970 Nova./1969-70 Camaro w/o 4wheel Disc./1968-69 Nova-Chevelle. /1964-67 Nova-Chevelle-Camaro)"

[isucorvair]

Another internet result:

REAR BRAKE DRUM NON FINNED USED 10 12 BOLT REARS CHEVELLE CAMARO 3841198

[66vairguy]

Per the internet

"rear brake drums GM #3841177
(WILL FIT 1970 Nova./1969-70 Camaro w/o 4wheel Disc./1968-69 Nova-Chevelle. /1964-67 Nova-Chevelle-Camaro)"

I recall the Corvair LM rear drum was only on FRONT of the cars you list. Not positive.

[Rotary FP46]

All of this is why I'm asking about a separate reference book for the drums.

Will dig the drums back out for measurements once I'm done identifying and cataloguing the camshafts. Limited working space at the moment.

[RexJohnson]

Some drums of that era had different hub hole dia. It might be a good idea to use a Corvair hub to see if they fit?

[66vairguy]

Some drums of that era had different hub hole dia. It might be a good idea to use a Corvair hub to see if they fit?

Good idea from Rex. There are arguments about the Corvair drums being "lug centric" or "spindle hub centric". As best as I could determine the OEM drums were primarily "spindle hub centric" after fitting stock OEM drums on LM's. Not sure on EM, but the front drums were often riveted to the spindle hub. Folks that remove the rivets have not reported issues with the drums staying centered.

If the drum spindle hub hole is too small, well it won't fit. If too large, then probably the lug holes will keep it centered --- MAYBE!

[RexJohnson]

The drums have to be centered on the hub. Tapered lug nuts can center the wheel but the drum just gets pinched in between the hub and the wheel so it would fall to the bottom before you tightened the wheel. I got some aluminum finned drums off of a later model GM car for the front of a Corvair and the hole was to small. I put the drum in a lathe and opened up the hole and then hub centered it on a Corvair hub to turn it on my brake lathe.

[Rotary FP46]

Show a picture with a tape measure somewhere.

Front:

Rear:

Per the internet

"rear brake drums GM #3841177
(WILL FIT 1970 Nova./1969-70 Camaro w/o 4wheel Disc./1968-69 Nova-Chevelle. /1964-67 Nova-Chevelle-Camaro)"

I recall the Corvair LM rear drum was only on FRONT of the cars you list. Not positive.

If those forums are to be taken at face value, the Corvair fronts fit the rear of Camaros, and the Corvair rears fit the front of a whole bunch of things. I don't have a way to confirm.

Some drums of that era had different hub hole dia. It might be a good idea to use a Corvair hub to see if they fit?

Good idea from Rex. There are arguments about the Corvair drums being "lug centric" or "spindle hub centric". As best as I could determine the OEM drums were primarily "spindle hub centric" after fitting stock OEM drums on LM's. Not sure on EM, but the front drums were often riveted to the spindle hub. Folks that remove the rivets have not reported issues with the drums staying centered.

If the drum spindle hub hole is too small, well it won't fit. If too large, then probably the lug holes will keep it centered --- MAYBE!

As it turns out, I've come across a crate of LM front spindles.

Seems the 1177 drums I have are hub-centric.

[RexJohnson]

All drums are hub-centric because they have to be centered to the spindle. The lug nuts will not center the drum.