My Aluminum Drums Fit!!

[Phil Dally]

Slipped right on... no clearance issues with the race tires.

I'll assume the guy that had them before me drilled them.

I heard they need drilling for stock...and I'm running 1/2"X20 studs.

[65Ragtop]

Hello Phil and anyone else out there who reads this. Are these Buick GS front drums circa 68-72? For some reason they don't look like it to me but I have not seen any for many years. I could be wrong. I've been looking for some for awhile now and they seem to be a kin to the proverbial hens teeth. What I was really wishing was that there was another doner source I did not know about. Any info would be cool. I have several sets of the front finned aluminum drums and would like to match the rears.

I will go to finned cast iron if I don't come across some eventually. Anybody out there got any info on good sources for these? I can find new finned iron replacements for the GS items and can machine to fit. I am just trying to widen my horizons here. Options are good. Thanks.

[Phil Dally]

There is a pile of these on e-bay.

[65Ragtop]

OK. I've been searching the Buick specific and Antique junkyards all over the net. No dice. I go to e bay once every couple of months more out of curiousity than not. Found some out of spec units there once. I guess I am going to have to bite the bullet and haunt the place until some good ones pop up. Thanks for the info.

[Phil Dally]

P/M sent

[cjwhite]

Is your use of these primarily for weight reduction or heat dissipation (or both)?

I haven't come across this before - just curious...

--chris

[65Ragtop]

Hi Chris.

Both, plus aesthetics. As I am sure you are aware, brake choice and other mods are application specific. In my case, I am building a performance GT car, street driven regularly. Finned aluminum drums are an "old school" performance modification which makes sense on a street driven car (to me). Here is how I see it.

Weight: You do save some weight when you use aluminum drums, more in the front than in the back due to the size of the rear drums. Clear advantage over cast iron there.

Heat Dissipation: Aluminum will dissipate heat better than iron, but iron is a better heat sink. Finned aluminum drums have been a favorite of racers for many years. 45 years of hind sight might suggest that there are durability issues under EXTREME racing conditions. The steel friction surface bonded to the aluminum drum expands at a much different rate under extreme heat/braking conditions often resulting in cracking and warpage. Stock and finned iron drums are much heavier but as far as I know there are no such issues with them. The weight difference can be made up in other ways such as the use of light weight wheel/tire setups. The Corvair braking system was actually designed for a car 1000 pounds heavier; so the stock brakes set up properly work great under normal driving scenarios. Under normal perfomance street driving conditions, the finned aluminum drums will probably never reach the design thresholds that are exceeded under racing applications and thus should be a superior choice for that use.

Just a note. If finned aluminum drums are used you will have to move up to 14 inch or larger rims as they are a bit larger. I have heard of people machining down the finns a bit to get them to work with the 13 inch rims but I am not sure I get the point. Just me, doesn't matter. So long as they are happy with it.

Don't quote me on this but I think the sanctioning bodys (racing) have changed the rules some a few years back and now allow era/manufacurer specific disc brakes to be adapted to/used on Corvairs and still be class legal. Seems the way to go for the road coarse, if true. The Race guys know more about this topic I'm sure.

There are disc brake set ups readily available for the front of the Corvair. This configuration does not make sense to me from an engineering perspective. In my opinion, if you were to go with a disc/drum set up it would make more sense to put the disc's on the rear wheels. 4 wheel disc's make a lot of sense but requires a certain amount of fabrication on the enthusiasts part. I will do it on my next car probably. I am watching the various threads here and elsewhere on that topic with great interest.

Aesthetics: Finned aluminum drums are a beautiful thing to look at! (yes, I am a sick man) I am running some very "open" wheels and the stock drums just look out of place and plain jane. I am not ready to do the 4 wheel disc thing yet so "old school" it is.

A lot of this is just my experience and my opinion. Run it throught the logic test on your own and see if it pans out. I am willing to learn more on this topic as well if anyone else has some input.

[Phil Dally]

MIKE: Your info passes the logic test for sure!!

[lonestranger]

Hello Phil and anyone else out there who reads this. Are these Buick GS front drums circa 68-72? For some reason they don't look like it to me but I have not seen any for many years. I could be wrong. I've been looking for some for awhile now and they seem to be a kin to the proverbial hens teeth. What I was really wishing was that there was another doner source I did not know about. Any info would be cool. I have several sets of the front finned aluminum drums and would like to match the rears.

I will go to finned cast iron if I don't come across some eventually. Anybody out there got any info on good sources for these? I can find new finned iron replacements for the GS items and can machine to fit. I am just trying to widen my horizons here. Options are good. Thanks.

These could also be off the buick wildcat of that era. That is what I have on rear of my 66 coupe and 78-80 buick/chev malibu station wagon aluminum rear drums on the front of the 66. They both have the "visual" fins and work well for drum brakes. Just a thought. My 66 has a built counter-rotating buick 215 in the rear hooked to a HD PG with a 4 spider posi differential. It does have 16" IROC wheels now and also used 14" front and 15" rear rally wheels prior to the IROC wheels, so I know these clear the drums with no problem - however I never tried them with 13" wheels relative to clearance. Hope this helps.

[65Ragtop]

Thanks for the info. I am always on the lookout for some good finned aluminum drums, locally. I am a bit of a junkyard phantom. Front ones seem fairly common but the rear ones are a challenge. I did mangage to find some thanks to a forum member. Your car sounds like a great ride.

[lonestranger]

Thanks for the info. I am always on the lookout for some good finned aluminum drums, locally. I am a bit of a junkyard phantom. Front ones seem fairly common but the rear ones are a challenge. I did mangage to find some thanks to a forum member. Your car sounds like a great ride.

Thanks for the complement and good hunting! After all, the chase is half the fun!!

[kevin.poe]

The Wildcat drums should be the full sized GM bolt pattern and are also bigger in size (I think they are an 11" drum as opposed to the 9.5 inch Vair and mid-sized drum). Back when I was hunting through salvage yards in Greenville looking for the right drums for my Buick I could find the big ones all day long but rarely found the smaller drums.