By Chuck Phlegm
There comes a time when you just have to face facts. My 1975 Bronco (better known as Crazy Alice) was in dire need of brakes. I had seen the signs of fluid leaking for some time. In fact, I carried a quart of brake fluid in case the resevoir needed topping off. Don't get me wrong, I'm not one to flaunt death by driving a car or truck with suspect brakes (much). Alice isn't a daily driver. With only three good wheels stopping her, she was pretty much retired to short trips within the neighborhood whenever I needed my Bronco fix.
I had begun the task of getting the parts together almost a year ago. Several other web sites detail the shopping list you need. Some even list the prices (which was helpful for me, but not very accurate). My own list began when I found a Chevy Truck guy who would sell me the spindles and backing plates from a '72 Blazer for $50. After that I scrounged a pair of hubs off a '79 Bronco and a really crappy pair of calipers to use as cores for a new set. I got all the bearings and a new set of rotors from various sources.
So, here is what I got:
__ 1 pair of spindles from a 1972 (other years work as well) Chevy Blazer
__ 1 pair of backing plates from the same '72 Blazer
__ Hubs from a '79 Bronco
__ Rotors (new) to fit that '79 Bronco
__ Calipers (I got mine loaded with pads & everything else) for a '75 Blazer
__ Flexible brake lines for that same '75 Blazer (part #77028)
__Banjo bolts (7/16-20X1-1/16")
__ Inner and outer wheel bearings (BR35/BR37)
__Hub Seals for '79 Ford Bronco
__ New wheel studs
Pre-installation
I cleaned all the used parts. I even painted the Chevy parts Ford Blue so they wouldn't stand out. I took the hubs in to the local parts store. For $10 per hub they removed the old races and installed new ones. They also packed the wheel bearings for me. The old wheel bearings were pretty bad.
Once you have the bearing surfaces all dealt with, you can attach the hub to the rotor. The wheel studs hold them together. Mine were separate. The parts guy said I should machine the hub and rotor mating surfaces. I declined. I could have also had the parts store press the wheel studs onto the rotor/hub assembly. Roger Bell recommended using the good old BFH to pound them on. The BFH worked beautifully.
I checked and rechecked the parts list to be sure I had everything. My Bronco has the dual resevoir master cylinder, so I didn't bother changing it out.
Brake Day
Max showed up about noon. We decided lunch first before tearing into the project at hand After we made oursleves ill on Mad Greek sandwiches, we could put it off no longer. Typical Oregon weather for that day, so surgery would take place in my garage. Alice was soon up on jackstands with wheels off.
We removed everything until we got to axle stubs. Starting with the locking hub stuff. I had done a Warn hub replacement, so that's what I was dealing with. Keep all the parts in a place where you can remember how they go back on. Take a polaroid or digital pictures if you need to. After the locking hub stuff is gone you will need a spindle nut tool (basically a big socket, but you can find it at most parts stores or from any friend who has ever worked on his/her Bronco). There are 3 parts to the spindle nut. Remove the outer nut, and then there is a thinner ring that has holes at various places around its perimeter. You can pull this out by hand or with a pair of needle nose pliers. You will be reusing all of this, so be nice. After you get that part off, use the hub tool to remove another nut similar to the first (except it has a small indexing pin that sticks up). Remember that this is the inner nut when you go to reassembly. After these pieces come off, the brake drum and hub should just about pop off on its own. You won't be reusing these, so get them out of the way.
There are 6 bolts that hold the backing plate and all the drum brake parts together along with the spindle. Take all these off (you can reuse the bolts to attach the new spindle and backing plate). With the spindle off, the axlee stub should be sort of hanging out.
The backing plate is still attached by the flexible brake line. Move it out of the way, but don't take it apart just yet. We aren't ready to get brake fluid all over the garage floor for a few more minutes.
The Chevy backing plate and spindle bolt right up. The reason this all works, of course, is because this front end was manufactured by Dana and Chevy., Ford and Jeep all used the same Dana 44 for their 4X4 trucks. Set your spindle right on the knuckle. The backing plate goes right on top. Use those 6 bolts to attach these parts to your knuckle.
Next we install the hub/rotor assembly. First install the hub seal with a flat piece of wood and a few taps with a hammer. Then get your freshly packed wheel bearings ready. They are not the same size, so it should be obvious which goes where.
Once the inner bearings are in place, slide the whole assembly over the spindle. Then you can install the outer bearing.
Now we come to the only opportunity you will have on this upgrade to do any real fab work. Your knuckle will not quite work with the disk brake caliper. What you need to do is grind off a bit of material on the knuckle and/or the caliper. The knuckle has a little more material to give up, but I decided to grind both surfaces. I had removed enough material when there was about 1/4" of space between the caliper and the knuckle.
With that removed, the calipers bolted right on. Remember that the bleed screws should face UP.
You can re-install all the locking hub stuff now too. There are 2 snap rings. The smaller of the two did not go back on due to the differences in the Chevy and Ford spindles. That is normal for this swap. the larger snap ring is sufficient to hold all the hub guts in.
You now have something that looks a lot like disk brakes on your Bronco. The only thing left is to run the flexible lines. I got a bucket out to catch the brake fluid that spilled when I removed the old line. A 3/8" flare tool is needed here. I ended up rounding off the old brake fittings anyway and used a pair of vice grips to finish the job. After the brake fluid was done leaking, I attached the new flexible lines right up to the hard lines.
After that they kind of loop around and attach to the caliper. They only fit one way, so it should be obvious how it works. The lines are attached with banjo bolts. These were a little tough to find in the right size. Once they were snugged down, all that was left to do was bleed the brakes. Since then, I have paid attention to the brakes, checking every few days for signs of leakage. So far, so good!
My perception of the quality of these brakes is a little colored. With the old leaky drum brakes, I had to pump several times to get ANY braking. The only good thing was that Alice only pulled in one direction instead of the "guess which way I'll go THIS time you hit the brakes." With the disks, that is all gone. The pedal feel is good. the Bronco brakes straight and sure every time. I could opt for power brakes at this time, but the manual disks feel pretty good, and since I am running 31X10.50 tires, I don't really see the need.
-Chuck Phlegm-
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