Thread: Juice Brakes....

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G'day,

Was just wondering if anyone could tell me what I'd need to do to convert my stock model A 'rod' brakes, to that of '39 Juice, or '42-'48, and if there is a difference between the two, (except stud pattern) ie, can you use 42-48 drums on the '39 setup. I've got the stock front and rear ends. It's still running the 'A' Banger.
Thanks guys.

Outback

Okay outback, lots of choices.

Based on the way you've phrased the question I assume you're wanting to stick with the old Ford stuff so various disc brake stuff is out of the question. You mentioned the '39 (first year of hydraulics on Ford), and I presume you know that that is the only year with the open center wheel/hydraulic combination (similar to VW's beetles of the early years), thus your comment about the lug pattern being different than the Model A. From '40 on up, they used the more typical 5 bolt pattern on a 5 1/2" circle, same as the Model A. The only drawback I can see with using the '39 is that your backs won't match the front, unless you put '39's back there too. It does give it kind of a cool track racer look.

Switching to the hydraulics in the back is pretty straight forward. Get the entire brake assy, backing plate, all the shoe/spring/etc peices, and the drum from any of the other years. You probably already know, but for the benefit of others, you can't just swap entire rears with the later models because of differences in spring hangers and drive shaft/torque tube length.

In the front there are a few more options. The way most guys do it is to swap to the later spindles and matching backing plates on out to the drum. The '39 and '40 pieces are identical, with the exception of the drum as noted. The '41-48's are different from the earlier pieces in that the mounting flange on the spindle is flat across the top as opposed to being round. Of course the backing plate is configured accordingly. You could rig up the later backing plates to mount to the earlier spindles by grinding down the top of the spindle, but........I'd only do that if I were forced into getting the parts piecemeal.

You can put the '39-40 brakes on the Model A spindles, but it requires an adaptor ring. The center register on the A spindle is smaller in diameter than the later pieces, so the adaptor ring is needed to maintain proper orientation. These are generally available from Model A parts sources as it is a fairly popular swap. Again, the '41-48's are configured differently at the mounting flange, so that's not real doable on the A spindle.

Just a brief discussion on brake design, then on to other Ford based options. The standard Ford passenger (and light truck) brakes are based on the Bendix design. That is, the shoes are bolted on a pivot at the bottom, and the wheel cylinder pushes them at the top. Each shoe has an adjustment bolt/cam to maintain clearance to the drum. These are not what is called self engergizing. Which is to say, you have to stand on them hard in a critical braking situation. Hydraulic pressure is doing all the work. This design is opposed to the Lockheed style which is the drum brake design we're most familiar with. That is the one where the shoes are held to the backing plate by small coil springs and the shoes are allowed to "float" to some degree. The benefit is that when the rotational forces of the drum contact the shoes there is somewhat of a "wedging" effect that multiplys braking force. A much better system for drum braking than the Bendix design. Another benefit of the Lockheed style is that the two shoes are linked through the star wheel adjuster at the bottom that allows you to uniformly adjust both shoes simultaneously, making brake adjustments WWWAAAAYYYYYY easier.

If you can find them, the '39-48 Lincolns (because they were heavier cars) had the Lockheed style brakes and the backing plates had the same register hole size, and bolt mounting pattern as the Fords (and Mercuries for that matter). These are hotrodder gold today, with the emphasis on "nostalgia". So much so that there is now a company here in the States that is reproducing them, Wilson Welding. They seem a little spendy to some folks, but you get a complete set of brand new backing plates and brake hardware for approx $400.00 per axle. Once you price out getting all newand used parts for the swap of the old Ford stuff, it doesn't seem quite as high. You would still need to get good drums. I recently sold a set of '40 front brakes for $200.00, all used parts. That seems to be the going price here in the US right now. Spindles are running about the same, sometimes a bit less depending on condition.

One other alternative, at least for the front, that is still nostalgic, though from a bit later era, are the brakes from the '53-6 Ford F100 pickup. My memory tells me that these are pretty much a bolt on situation, may require some modest machining of the center register. Sorry, can't remember that one as well. The backing plates look very similar to the earlier Fords, and the truck pieces also have the self energizing brakes, and the 5 1/2 in bolt circle.

Don't forget, you'll need a way to mount the master cylinder. Again, the '39-40 has a pedal assembly that gives you both a brake pedal (with the necessary master cylinder mount) and a clutch pedal that is configured much like the one you probably already have. As for master cylinders, from a safety standpoint you would be better served by a dual chamber one, rather than the single chamber as the early Fords had. A good one to seek out is a '67 Mustang, drum brake front and rear, unit. If you use the Ford pedal assembly, adaptors to mount the three bolt Mustang unit, to the two bolt Ford bracket are readily available from nearly every hot rod parts supplier.

Wow, thanks Bob,

That's been very helpful,
Yeah, I want to stick with the early stuff,
I've access to a complete set of rebuilt '39 brakes, so that's my interest there, and I also have access to a set of backers for the 42-48 set up, but alas no drums. As far as I know the Lincoln/F100 stuff is pretty hard to find over here, (more so than over there) I havn't gone looking for yet, though. I'll keep it in mind and an eye out for it!
I've got a set of widened 35 wires so I would love to keep them, however I don't mind going with the 39, spider type to get brakes. We don't have so many Mustangs over here, but I suspect that our Falcons may be a good alternative, mechanically they were based on the Mustangs.

Thanks again, it's way better hearing it from some who knows, than someone who thinks it might..... And making mistakes learning how.

Outback