46 brake drums

M

mrcorvair

Senior Member
How are the drums different when you have internally mounted hubs vs externally mounted hubs? Can you tell by just looking at the drums?
Which is preferable external or internal? Thanks again Ford Barn.
 
Got one of each on the rear of the A-V8...
Can't tell the difference.

Figure that the inside mount drum will be a lot shallower the outside one... I could measure the outside mounted drum if you want-

Karl
 
If you are looking at loose drums, the internally mounted drum will have a fairly large center hole that is flush with the outside surface, the externally mounted drum will have a smaller, more average looking, size hole with a slightly raised lip.

If you are looking at drum assemblies, the flange will be evident on the internally mounted drum.

If you are looking at loose hubs, the internally mounted hub will have raised ribs on the inside where the studs pass through, the external mounted hubs may or may not have a raised area on inside where the studs pass through; but will be flat where it seats against the drum face.
 
rich b said:
If you are looking at loose drums, the internally mounted drum will have a fairly large center hole that is flush with the outside surface, the externally mounted drum will have a smaller, more average looking, size hole with a slightly raised lip.

If you are looking at drum assemblies, the flange will be evident on the internally mounted drum.

If you are looking at loose hubs, the internally mounted hub will have raised ribs on the inside where the studs pass through, the external mounted hubs may or may not have a raised area on inside where the studs pass through; but will be flat where it seats against the drum face.
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Also, those loose drums will have holes that measure 3 1/4" on the '39-'42's and 4" on the '46-'48's.
 
Here are a few photos of 1940 front and rear drums. The hub is mounted on the inside. The measurement from wheel mounting surface to wheel mounting surface is 59 1/2 inches. Maybe this will be helpful.
 

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Not to hijack, but I'm looking for a pair of front 1940 Ford brake drums/hubs that are useable and within factory specs.
 
With the inside hub are they still swaged or are the drums removable (slip off) as on later units. Zeke
 
The hub behind type are swedged from the factory. I was going to say the hub in front are too, but I'm not sure.

Mart.
 
Is there an advantage of external hub vs internal hub?
How are the hubs removed from a drum that you are replacing?
Unfortunately I just bought drums from Speedway which appear to be for internal hubs. The machine shop which is 60 miles away is saying that the old unusable drums are for external hubs. So now I'm faced with a dilemma. It would cost too much to return the hubs to Speedway...
Thanks for all the helpful answers.
 
To remove studs the swadged part must be cut. There is a special tool, but I just cut off the stud about halfway and use a rotobroach bit to cut it, then use a drift and punch it out. You can also drill head of stud out to the hole size if your careful, and punch it out the front.
 
mrcorvair said:
Is there an advantage of external hub vs internal hub?
How are the hubs removed from a drum that you are replacing?
Unfortunately I just bought drums from Speedway which appear to be for internal hubs. The machine shop which is 60 miles away is saying that the old unusable drums are for external hubs. So now I'm faced with a dilemma. It would cost too much to return the hubs to Speedway...
Thanks for all the helpful answers.
Click to expand...


Unless things have changed; the replacement drums for external hubs were not the best quality, maybe better off to get a set of internal hubs. Usually cheap to find with worn out drums, easy to cut the swedges with a 5/8" holesaw and knock out the studs yourself. The new drums from Speedway are made for the aftermarket serrated studs; the repop cast iron drums don't take to swedging the OEM style studs and they would probably be to short anyway.
No need for a machine shop until you have them together, and then just a light turn to true it all up. Sell your external hubs to a hot rodder for use with finned Buick drums, they are worth more than internal hubs.
 
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