Drum brake ID

[biggieou]

Here’s the story, I have four front drums I’m trying to ID. I know two are from a 48 F1 and two are from a 50 Mercury, both of which I converted to disc. I now can’t remember which are which and want to begin stockpiling parts for a Model A juice conversion.

[19Fordy]

The front drums and backing plates on my 51 Merc look like this. They are the same as 1949 and 50. Both yours are very similar to the Merc but, I think the backing plate on the right side of you photo is the Merc. due to the spacing of the backing plate bolt holes.

The holes in you left photo seem narrower in one direction.
PS: Mine are for sale if you need them. Click and open link.
https://www.fordbarn.com/forum/showt...mercury+brakes

[V8COOPMAN]

Are the Merc and F-1 diameters the same, or different? MAY be a way of distinguishing. DD

[51 MERC-CT]

Mercury and F1 are the same diameter. (11 inch)

[rich b]

The one on the right is F-1.

[Mart]

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^^ That's what I would say. F1 on the right. The give-away is the 4 mounting holes in an equal pattern. The other one seems a bit deeper drawn in the middle and the bolt holes do not look equal.

[19Fordy]

Here's a few more photos of my 1949-51 Merc car front brake drum assembly with dimensions that may help better determine what you have. Brake drums are 11 in. Bolt pattern is 5 x 5 1/2. Backing plate center hole dia. is 3 in. Backing plate bolt holes dia. is 1/2 in. Depth of recess of "backing plate offset", is 1/2 inch deep as measured with a combination square depth gauge. Backing plate bolt holes have "X" and "Y" center line bolt hole dimensions of 3 in. and 3 5/8 in. There is a # 48843 stamped into backside of backing plate.

Please let us know if you conclusively find out what you have. Thanks, JIM

I still think your Merc backing plate s on the right based on BP holes.

[biggieou]

Thanks for all the feedback and pictures! Been tearing down an A engine for rebuild and then my 68 took a dump yesterday. I’ll get into the shed and get better pics and measurements.

[rich b]

Another clue; the F-1 bolt pattern is square and clocked to rotate the backing plates rearward. This results in the plates being side specific.