brake drums, 39 Ford

[JD]

I have a set of really good brake drums, 78 part number, which I'm planning to use on my 39 Ford. I can't see any reason why they wouldn't work for the 39 hydraulic set-up, even though they are 37 drums. Does anyone know if there is anything to caution against this?

[Chet/Ma.]

Being cut oversize is the only problem that I know of. Be sure the races are not pitted and there are no heat cracks. 36 drums will not work on 39, but 37 will work ok.

[39portlander]

JD, I'm not using my front or rear drum brakes off my 39 1/2T. If interested email me @ [email protected]. I'm using ECI disc front's and linc/zeph rear drums for the rear. I wanna stop on a dime!

[cuzncletus]

Let me ask the reverse question: Will 40 and up drums fit on a 39? I'm gathering parts (mostly off my 39) for a Vern Tardel style roadster. I'm planning on using the wide 5 16's, but may decide to change in the future.

[V12Bill]

I have 1937 Drums on my 39 PU and Lincoln Zephyr backing plates/brakes.

[Richard (EV8G)]

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Wide 5 Hubs/Drums 1936-1939:

1936 FRONTS have the drum/shoe surface offset 1" inward, so cannot be used with Ford/Merc/Lockheed hydraulic brakes. When converting 36's to these brakes, must use 37-39 fronts. 36 fronts CAN be used with 39-40 "deep" Lincoln-Bendix on 36 spindles by also using a special kingpin/bearing kit that eliminates the "socket" at the top and relocates the bearing/load to the bottom of the axle by using special thin thrust bearings.

1936 REARS have the same offset as 37-39 REARS and can be used with hydraulic brakes.

1937-39 FRONTS and REARS have the same offset as 39's and therefore can be
used with hydraulic brakes. Note that there are "one piece" and "two piece" hubs/drums and most or all 36 rears and some 37 rears use the larger rear grease seal.

To convert a 36 from "Wide 5" to "5-on-5-1/2" need to replace all 4 hubs/drums with 40-48's; note that there are variations within those years. IF using the 39-40 "deep" Lincoln-Bendix mentioned above, or if still using mechanical brakes, can use 35 FRONTS (and rears) but note that if not using wire wheels, the (5) "stands" on the inside of the bolt circle must be machined down to the same level as outside the bolt circle so that the drum mounting surface is FLAT. (In the past, there have been spacers available that install on the OUTSIDE of the bolt circle, but doing that reduces the threads available for the lug nuts = unsafe condition.)

To convert a 37-39 to "5-on-5-1/2", can replace all 4 drums with 40-48's; there are variations within those years.

[Bruce Lancaster]

And...the "78" 1937 prefix marks the introduction of that part; it was used through 1939 unchanged and with same number, as done with all Ford parts that were used for more than a single model year. The 78 drums will not only fit a '39, they are what the factory put on it in 1939.
Ford did not normally change the number of a part unless there was a design change.

[Richard (EV8G)]

And: There are several variations of "68" prefix drums for 1936. Most have fins around the circumferance, which are often broken. Some also have an extra flange at the outer edge that is taller than the usual fins.

There are also 37-39 one-piece that have much shorter fins that are more like "bands" and were most likely intended to strengthen the drums to keep them round when hot??? These are interchangeable as to fit, but definitely of different design and appearance. Do not know if Ford assigned a different
suffix to the part number???

[Bruce Lancaster]

From memory...the different drums came from different suppliers, and I believe they had suffixes to sort them out, but I don't think the suffixes were used in the dealer parts books...they were considered entirely interchangeable. I think the suffixes are in the resto book, and probably are from the drawings.

[JD]

Thanks, this has been a great help; I can use the '78' drums with confidence. John

[Dennis Jarrell]

I'm very new here to all of this. I have 35 that I want to convert to hydraulic brakes. During the conversion I also plan to add a new dropped axle which means (I think) 37-41 spindles. I plan to keep the stock rear axle. If I'm reading the above correct, I can use the original 35 drums front & rear with 40-48 backing plates and hardware? Which hubs?

Thanks,
Dennis