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T-Bird caliper swap

65264 Views 155 Replies 37 Participants Last post by  Mister Sunday
OK, I know this has been done before ... I plan to do it a bit differently.
parts list
2 x 7/16-24 Banjo bolts @ $9.95cdn ea. (these are a motorcycle part so NAPA won't help) Russell part # R40515
2 x 78 T-bird calipers @ $24.99cdn ea (the measly $2 core included) pick through the boxes as they come in both Phenolic and Steel pistons with no differention in part numbers. I chose Steel pistons, I hate Phenolic.
2 x 77 E-350 rubber flex hoses @ $31.33 ea part number to follow when they arrive (2 weeks) your stock hoses will work if you drill the center out to 7/16" (use a drill press for this or it may leak) and do a little grinding (this will be included in the write up as I already did it) but since mine were shot I perused the raybestos website and found the ones I liked.
this is just the teaser for now ... I'll post parts pics, and more info later. When the hoses arrive I'll start the install as I rebuild my 74 D44 with big brakes under 15" rims.
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OK, I'll ask the stupid question. Are these T-bird brakes that much better than stock bko brakes? Why? Couldn't you use some off an F-250/350? Just asking cuz I don't know. :brownbag
yes they are better. IIRC, they have a larger piston, making for greater breaking. This swap works on a solid 44, and allows you to retain the 5 on 5.5 instead of going to the larger one ton stuff.

THere is a really well done write up I read a year ago or so on broncofix.xom by a guy named Danny. ( I think thtas where I saw it)
Yes, please keep my posted, I am very interested in this swap since I plan on doing this on my HP44 with 8 lug outters. I would like to be able to retain the 15 inch wheels.
would this work on ttb equipped, but i have a feeling the answer is no?
if you have 8 lug outers, you will already have upgraded calps
it'll work on any TTB up to the point they changed to mounting PINS instead of the spring and key of earlier years.
I'll post links to the other write ups to make this as complete as possible. in the past swaps alot of special parts were use driving up the price ... My way requires only the banjo bolt and away you go ... the biggest problem was finding the banjo bolt.
FYI the t-bird calipers produce a slight amount more braking force than the 3/4 and 1 ton dual piston calipers AND fit just fine under a 15" rim. If you've ever tried to find a decent mud tire that doesn't cost and arm and a leg in 16" size you'll see the reasoning.
Got data? I can see it being an upgrade to stock calipers, but, I don't see them out-braking a dual piston 1 ton setup.

Saying it's the best brakes for a 15" setup would be more believeable.

Bob K.
IT sounds worth it if it is as easy as you say. Keep us posted!!
Here's data if you wish ... these guys have already done the math, I just tweaked the install a bit with less custom bits.

It's all in the size of the piston.
for thnose that don't want to read the links -

The front brake calipers on our Broncos are weak because of their small 2 7/8" pistons. The phenolic (plastic) piston is also undesirable. These calipers are another major factor of our Broncos poor braking. The brake calipers we want are off of '73-'78 Ford fullsize cars. For the sake of arguing, I will be calling these fullsize car calipers the Thunderbird calipers. These calipers have a thicker casting, a huge 3 3/32" steel piston and are a direct fit replacement on our Dana 44 axles! The Thunderbird calipers even use the same brake pads. What will amaze you more is the clamping force of these calipers. In order to put its power in proper perspective, we need to understand what's called a caliper's piston area. caliper piston area is the measure of a brake calipers clamping force. It is found by first finding the decimal equivalency of the piston diameter and multiply it by itself to find its "squared" value. Then multiply that figure by .785 and the result is the caliper piston area. Let's first compute the Bronco's caliper piston area. 2.875 X 2.875 X .785 = 6.48 square inches of clamping force. If we compute the dual piston caliper of an F350, the only difference is finding the piston area and multiply it by 2, because this dual piston caliper uses two smaller 2 3/16" pistons instead of one large one. 2.187 X 2.187 X .785 X 2 = 7.50 square inches.

As you can see, the F350 dual piston caliper has over one square inch of piston area and in terms of hydraulic pressure, one square inch is a very potent difference in clamping force. Now let's compute the Thunderbird caliper with its 3 3/32" piston. 3.094 X 3.094 X .785 = 7.51 square inches of clamping power! Remarkably, we have just swapped in a brake caliper equal in strength to an F350 dual piston caliper and it fits inside the 5 lug, 15" wheel!

The only implication is plumbing the Thunderbird caliper. It has a 7/16"-24 inlet hole as oppose to a Bronco caliper having a 3/8"-24 hole. The Thunderbird caliper also never used a banjo bolt, the hose itself threaded into the caliper with a crush washer. We need the ninety degree angle a banjo bolt provides, in order to clear the upper ball joint on our Dana 44 axle. Since a banjo bolt was never used and 7/16"-24 is unusual, we need to convert to a #3 AN fitting.

The last bit is the part I solved by locating the proper banjo bolt (and a simple mod to the caliper)
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what was the proper banjo bolt size and the caliper mod? im kinda curious because im about to redo the whole braking system in a 86 i am about to put on the road and i want to do the braking system right the first time.
Haven't had much time lately ..
Update - hit the wreckers looking for the right banjo fittings .... Dodge Ram 100 4/2wd hoses are the perfect fit, looks like all dodge brake fittings are 7/16" banjo's .... Vans and trucks all work. Have a friend making me new SS lines so I'm after just the fittings (I'll use the van lines I bought for the rear disc)
added to total - 4 x dodge used brake hoses, AND '93 F-250 1 1/8" bore Master cylinder (saw it all lonely gleaming at me so :shrug couldn't beat the price) - $20
Mods - I'll transpose this whole thing up to one post when I'm done, so it can be cleaned up a bit :brownbag
Rockfrog said:
Mods - I'll transpose this whole thing up to one post when I'm done, so it can be cleaned up a bit :brownbag
Thanks! Lookin good so far, seems like it'll be a pretty decent write up when done.....:beer
if you have a solid 44 with 8 lug outers, you will need the old caliper brackets from when it had 5 lug stuff. the dual piston 3/4-1 ton stuff uses a caliper bracket that has a bigger gap in it to hold the T-bird calipers.

you can also use 2.5" back spacing 15" inch rims on your 8 lug axles with little or no grinding
I'm missing what yer getting at Ax ... My D44 is a 74 converted to disc with 76 parts all 5 on 5.5. the T-bird calipers fit my 1/2 ton brackets perfectly (same casting, bigger piston though).
thi swap also works for any Bronco that has the key and spring caliper retainers (so basically good up to 84 and possibly later depending on the retainers)
SMOOTH said:
Yes, please keep my posted, I am very interested in this swap since I plan on doing this on my HP44 with 8 lug outters. I would like to be able to retain the 15 inch wheels.
sorry. that was directed to the D44 hd comment. 44HDs were 8 lug, but can be converted back to 5 & t bird brakes. i wonder if you could drill D44 5 lug hubs for 8 on 6.5? you cant have 8 lug rotors & T bird calipers can you? you would need to have all the parts & try it all out.

SMOOTH said:
Yes, please keep my posted, I am very interested in this swap since I plan on doing this on my HP44 with 8 lug outters. I would like to be able to retain the 15 inch wheels.

smooth, if you get 8 lug outers, you cant do the tbirds too, but you can keep 15 inch wheels to fit dual calipers, just need 2.5 backspacing.
hey rockfrog i am am pretty sure i know what the pin you are referring to is, my mums 87 has about a 3-4 inch long triangle thing holding the disc on with rubber in the middle of it, is that the newer style you are referring too. BEcause my 85 has a piece shaped like this: ^--^ except the arrows are more u shaped and then has a slight bowed piece of metal to act like a spring. SO i am almost positive my 85 would have the older style, i think 86 was the switchover year :shrug
I have seen an 85 with pins so as with all things Ford ... which way does the wind blow in outer mongolia on a Tuesday? Kinda like a 9" omn an 86 or a NP435 in a 94 (both supposedly discontinued at those time but guess what ... which way does the ...)
But yeah, that's what I meant by the newer Pins.
ok cool...i am goona have to get me some calipers, thanks fer the info. i am also think about ordering tsm's rear disc mounting brackets and rotors for 250 bucks or so and then have some better stopping power :brownbag
Quick question, Anyone kneo if the F-350 rear cylinder swap works on a 94? With e bigger tires I really need to improve my breaks.
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