Wilwood Dynapro 4R 12.19" Rear Disc Brakes, 76-77 Bronco SKU: 140-13322N

This group of DPL Pro-Series rear disc kits provides a complete solution for popular muscle car rear axles that require a parking brake. Forged Billet Dynapro Lug Mount four piston calipers, 12.19" one-piece drum/rotors, and high friction pads provide optimized and balanced braking for all types of custom performance street/strip and show machines. The neatly hidden internal shoe system provides a clean installation with superior static holding power for parking. Optional caliper finishes and rotor designs enable the builder to personalize the style and optimize brake performance for every individual application.

Specifications
• Fits 1976-1977 Ford Bronco 3300 Lbs Axle, 11" Drum Brakes
• Pistons: 4
• Rotor Diameter: 12.19
• Caliper Mount: Lug
• Wheel Diameter: 15
• Flange: Big Ford
• Axle Offset: 2.36

Note: These kits fit LARGE BEARING ONLY. The easiest way to confirm what you have is to measure the OD of the bearing. 3 1/8"" is large bearing.

Note: Brake Kit does not include flex lines. Flex lines are necessary to complete the installation of the kit and must be ordered separately.

Note: Kit may not fit all 15" wheels. Check wheel clearance diagram in kit installation instructions before purchase.

CAREFULLY CHOOSE THE RIGHT KIT

Let's cover some basics. The rear end refers to the entire rear axle assembly. The different parts of the rear end are the brakes, axles, axle housing, and the third member. The most common question we are asked is "How do I tell if I have a large or small bearing rear axle?" You can easily identify if you have large or small bearing axles by examining the ends of the axle housing.

Photo 1 shows a small bearing axle housing. If you look close at the housing right where it meets the backing plate, there is no noticeable size increase where the axle bearing pocket is. Photo 2 and 3 show a large bearing axle housing and you can see a noticeable size increase where the axle housing meets the backing plate. If you have loose axles laying around, you can simply measure the outside diameter of the bearing. The small are 2.835" or just under 3" and the large are 3.150" or just over 3".


There are 4 different sets of rear axles that would have come stock in 66-77 Broncos. The original applications are as follows:
1. 66-75 small bearing,
2. 66-75 large bearing,
3. 74-75 medium duty large bearing, and
4. 76-77 large bearing.
Each of these sets have a driver and a passenger side axle. Each of these sets use corresponding backing plates and brake drums. The backing plates and drums are particular to each set and are not interchangeable with the exception of the 66-75 small bearing and 74-75 medium duty large bearing using the same brake drum.

So, how can you identify which large bearing set you have? it can be narrowed down this way: The inside diameter of the Bronco rear brake drum is approximately 10" or 11". So, if you have a large bearing and a 10" brake drum, you have what we call a 74-75 medium duty setup. That leaves us with the 66-75 large and 76-77 large. Both use an 11" brake drum. The 66-75 uses a narrower drum and corresponding brake shoes. We identify this as 11 X 1 3/4". The 76-77 uses an 11 X 2 1/4" drum and shoe. Note the difference in the backing plates * in photos 2 and 3. Photo 2 shows a 66-75 large bearing with 11 X 1 3/4" brakes. Photo 3 shows a 76-77 with 11 X 2 1/4" brakes. If you look close you can see the backing plate of the 66-75 appears wider. Please note that all of the original axle sets were 28 spline. See Photo 4. With an increase in spline count comes an increase in outside diameter of the axle and so you get an increase of strength. A very common upgrade is to install a set of 31 spline axles. All that is necessary to do this is a set of axles and a new differential and we would recommend a third member rebuild kit. 35 spline axles are another step up in the strength department but usually require a new differential housing. The 35 spline axle is common for the extreme rock crawlers.

The third member, also known as the differential housing, hogs head, and chunk, holds the differential, ring and pinion gears, and bearings. This is the part that bolts into the center of the axle housing. See photo 5. You have three choices of gear ratios that were stock. They would be 3.50 which is the most common, 4.11 and 4.56. There are many other ratios that can be used as well. The differential refers to the ring gear carrier and came stock either open or limited slip "posi" type. There are numerous upgrades such as Detroit Locker, ARB air locker, electric lockers, etc.