SAFETY CRITICAL — brake work is one of the few jobs where a mistake can kill you or someone else. Bleed thoroughly, double-check every fitting, and road-test at low speed before trusting the system.
> If your early Bronco still has front drums, converting to discs is the highest-value safety upgrade you can make — better stopping, far better fade resistance, and no more chasing a grabbing drum after every water crossing. Pre-1976 trucks need a kit; 1976–77 came with discs from the factory.
Front drum brakes on an early Bronco fade hard on a long descent, pull when one shoe grabs, and turn useless after a water crossing fills the drum. A front disc conversion fixes all three. Factory front discs arrived for 1976, so 1966–1975 trucks are the conversion candidates; 1976–77 owners should focus on pad and rotor refresh instead.
The honest tradeoff: a disc conversion is a real afternoon of work involving hubs, bearings, and a full bleed, plus you usually need to address the master cylinder and proportioning to match. Done right it transforms the truck. Done half-way — old master cylinder, no proportioning valve — it can feel worse than the drums it replaced.
A Bronco-specific Dana 44 front disc kit includes calipers, rotors, caliper brackets, new spindle hardware, and usually inner/outer bearings and seals. You also need a master cylinder rated for discs (a drum master pushes too little volume) and a combination or proportioning valve to balance front disc / rear drum pressure. Braided stainless flex lines are a worthwhile add — the original rubber lines are likely 50 years old and swelling internally.
Support the front on jack stands, remove the wheels, and pull the drums, hubs, and old backing plates. Clean and inspect the spindle; a worn spindle bearing surface needs addressing before the new hub goes on. Install the caliper bracket, pack and set the wheel bearings, mount the rotor and hub, then bolt on the caliper with new pads. Plumb the new flex line and combination valve, then bleed the entire system — start at the corner farthest from the master cylinder and work in. If you changed the master cylinder, bench-bleed it first.
Set wheel bearing preload to spec: snug while spinning the rotor to seat the bearings, back off, then finger-tight plus the cotter-pin slot — not cranked down. Over-tight bearings cook and fail; loose bearings let the rotor wobble into the pads.
Skipping the proportioning valve is the classic mistake. Front discs need more pressure than drums; without a valve to bias the system, the rears can lock early or the fronts feel dead. Adjustable proportioning valves let you dial it in.
A drum-era master cylinder won't move enough fluid for calipers — pedal goes to the floor. Match the master to the conversion kit's spec.
Air in the lines is the number-one cause of a soft pedal after the job. Bleed until the fluid runs clear with zero bubbles, then bleed again. A pressure or vacuum bleeder makes this far more reliable than the two-person pump method.
After assembly, pump the pedal until firm before you move the truck — the first pumps take up caliper clearance. Road-test at parking-lot speed first.
A Bronco-specific front disc kit runs $350–450. Add a disc-rated master cylinder ($60–110), combination/proportioning valve ($55), braided lines ($60), and fluid ($12). Total a realistic $450–700 depending on how much of the hydraulic system you refresh. Wild Horses 4x4, Toms Bronco Parts, and James Duff sell complete EB kits with matched components — buying a kit rather than piecing it together avoids proportioning mismatches.
| Part | Vendor | Est. price |
|---|---|---|
| Front disc conversion kit (Dana 44, EB-specific) | Wild Horses / Toms Bronco | ~$380 |
| Proportioning/combination valve | Various | ~$55 |
| DOT 3/4 brake fluid | Various | ~$12 |
| Braided stainless flex lines (pair) | Various | ~$60 |
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.