You can download these instructions as a PDF here: Dana 30 & Dana 44 Disc Brake Conversion Kit
Please read entire set of instructions before beginning disc brake conversion kit installation.
NOTE: grinding on the knuckle is required for this installation see diagram below.
Jack up the Bronco front axle and place it on jack stands. Remove the tires and wheels.
Remove the lockout hubs. NOTE: The factory locking hubs will not work with this kit. You must
use aftermarket locking hubs such as Warn or Milemarker. If you are installing new aftermarket
hubs, the original factory hubs may be discarded (everything from the lockout cap to the spring and
Using a Spindle Nut Socket (part #3220, sold separately), remove the large spindle nuts inside the hub
assembly. With these nuts removed, you can now remove the factory drum brake hubs and drums.
Retain the spindle nuts for re-assembly. The hub & drum assembly will not be re-used.
Disconnect the flexible brake lines from the backing plates. Drain brake fluid in a can or jar for proper
disposal, and remove flexible brake lines.
Remove the 6 bolts that hold the spindle and backing plate to each knuckle. Remove the backing plates
and spindles. NOTE: The spindle will be very difficult to remove, and may need “persuading”
with a rubber mallet and/or brass hammer.
Remove the axle shafts.
Using a vacuum cleaner, suck any dirt or debris out of the axle tubes.
. . . PROCEED TO KNUCKLE GRINDING
If using your old steering knuckles, grind the back side of each knuckle flat as shown in the
provided diagram. This is necessary for clearance of the caliper when it is installed.
With your steering knuckles properly ground for clearance of the calipers, you may proceed with
installation of your new Tom’s Bronco Parts Disc Brake Conversion Kit.
1. Reinstall Axle Shafts: Coat the inner axle shaft seal surface with grease or heavy oil to protect the
inner axle tube seal from damage and install the axle shafts.
NOTE: If you haven’t already done so, this would be a good time to replace the axle shaft ujoints
(Part # 3205). If your old u-joints are rusted to the axle shafts, you may want to cut them out
with a torch. If you bend the yokes, you will need to replace the axles.
With new u-joints installed (recommended) and inner axle shaft seal surface greased, re-install the
axles into the housing so that they are seated in the carrier.
2. Install Spindle & Backing Plate: To install the spindle, first mount the Spindle Bellow Seal (as shown in Figure 2 found in the “Installation Images” attachment). Then install the Spindle Thrust Washer (Figure 3).
NOTE for Dana 30 Installation:
For Dana 30 Installation, you will need a Dana 30 Spindle Seal which will be
used IN PLACE OF the Spindle Bellow Seal. Install the Bearing Seal, Thrust
Washer and Spindle Seal into the back of the spindle (See Figure 17 & 18). This
will require you to check if your outer stub axles have slingers or not so that you
can order the correct spindle seals (Figure 15 & 16)
You will then need to install the Spindle Bearing Seal into the back of the spindle (Figure 4 & 5). With
the spindle bearings & seals properly installed, you may now install the spindle (inboard) onto the axle
shaft (Figure 6 & 7). Now mount the Caliper Support Plate to the steering knuckle with the caliper
clearance cutout facing to the rear of the vehicle (Figure 8 & 9). Using the six grade 8 bolts and lock
washers provided, secure the backing plate and spindle to the steering knuckle. Torque the bolts to 35-
Now, check for clearance between the caliper support and the knuckle. If the knuckle is in contact with
the caliper support, relieve the knuckle for clearance (normally on the casting # area).
3. Install Hub & Rotor: To prepare the Hub & Rotor for installation, first pack your wheel bearings
with grease. With the inner wheel bearing well packed, install it into the back side of the hub assembly.
Now install the provided hub seal into the back side of the hub using a soft rubber mallet, taking care
not to bend the metal lip of the seal. Grease the seal. Now, slide the hub and rotor assembly over the
spindle (Figure 10). With the Hub & Rotor Assembly in place, insert the well packed outer wheel
bearing and then retain it with the spindle lock nuts using a Spindle Nut Socket (Part #3220, sold
separately). To properly seat the bearings, torque the spindle adjusting nut to 50 ft-lb while rotating the
wheel back and forth to seat the bearings. Then back off the adjusting nut approximately 90 degrees.
Assemble the lock ring by turning the nut to the nearest hole and inserting the dowel pin. NOTE: The
dowel pin must seat in a lock ring hole for proper bearing adjustment and wheel retention. Install
the outer lock nut and tighten to 50-80 ft-lb. Final end play of the wheel on the spindle should be 0.001
to 0.010 inch. The goal when installing the spindle nuts is to ensure the bearings are properly seatedand that when installed, the hub & rotor spins by hand but not too loosely (should have a bit of a drag
4. Install Locking Hubs: As a reminder, you MUST use aftermarket locking hubs with this
conversion kit. Referring to the manufacturer instructions for your locking hubs, install them into the
hub assembly. NOTE: The SMALL snap ring that mounts to the end of the axle shaft is NOT
used for installation. DISREGARD the SMALL snap ring that normally mounts on the end of
the axle shaft.
5. Install Caliper & Brake Pad Assembly: Install the loaded caliper assembly to the caliper support
with the bleeder pointing UP and toward the center of the housing (Figure 11 & 12). Make sure there is
at least 1/8” clearance between the caliper and the knuckle, grinding more on the knuckle if necessary
for proper clearance. (Figure 13) Torque the caliper bolts to 45 ft-lbs. Attach the flexible stainless
brake hose to the hard line at the axle. Attach the brake hose to the caliper using the provided banjo
bolt. Tighten all fittings at this time. The brake line should point up from its mounting point at the
caliper. (Figure 14)
6. Final Steps: Bleed the front brakes, starting with passenger side, to remove all air from the brake
system. Mount your wheels and tires torquing to your wheels specs, and carefully road test.
NOTE: You will not use the small outer 1” snap ring when installing the Locking Hubs.
2 x Hub & Rotor Assembly
2 x Hub Seal #4250
2 x Spindle w/Bearing & Seal Kit
2 x Caliper w/Pads
2 x Caliper Support Backing Plates
TIPS for Maximizing the Potential of your New Front Disc Brake Conversion
- When converting from drum brakes to front disc brakes or 4-wheel disc brakes, the factory drum brake H-block junction should be replaced with a Front Disc Brake Proportioning Valve or a 4-wheel Disc Brake Proportioning Valve.
- It is HIGHLY recommended when installing front disc brakes that you also install a Power Brake Conversion to fully utilize the new disc brake conversion. This provides better stopping power and also replaces your drum brake master cylinder with a properly bored disc brake master cylinder.