How to Put in a Disc Brake Conversion Kit

As handling and chassis dynamics replace acceleration as the dominant priority for today's hot rodder, rear disc brake conversions have become a de riguer upgrade for any older car. In a big way, disc brake conversions are a by product of the large, open area wheel trend that has arisen in the last decade. Style-conscious builders have noticed that large wheels expose everything behind them, including ugly old drum brakes.

Difficulty: Moderate

Instructions

Things You'll Need:

• Disc brake conversion kit
• Set of inner and outer wheel bearings (if required)
• Full set of 3/8 drive ratchets
• Full set of wrenches, including line wrenches
• Blue Loctite
• White lithium grease
• Wheel bearing grease
• Pry bar
• Flathead screw driver
• Rubber mallet
• Two ball peen hammers
• Penetrating oil

1. Raise the vehicle into the air with either a chassis lift or a floor jack. Do not engage the parking brake.

2. Remove hub caps (if equipped) and lug nuts. Remove tires to access brakes. If using a chassis lift, all tires can be removed prior to conversion.

3. Remove drum brake. Tap the drum on opposite sides of the rim simultaneously to ensure the drum comes straight off without hanging up on the wheel studs. Spray the wheel studs at the base with penetrating oil and allow to sit if necessary. Keep tapping gently around the perimeter of the drum until it can be worked loose by hand.

4. Remove the entire interior brake assembly. Generally, the brake assembly will unbolt from the back with either three or four bolts. Some vehicles will require new axle shafts and/or some welding or fabrication to the axle itself. Consult your kit manufacturer for details before purchasing.

5. Install new brake caliper mounting bracket as per kit instructions. The new brackets will generally utilize the pre-existing brake assembly mounting holes. Use Blue Loctite to secure bolts to axle housing.

6. Pack new wheel bearings with grease using the palm of your hand, making sure to get the seals as well. Some kits include bearings and some do not; check to see if yours comes with a new set before beginning.

7. Place new inner wheel bearing into the back (flat part) of the disc, with the conical side facing in. Tap around the perimeter of the bearing with a rubber mallet until the bearing seats in the disc.

8. Grease spindle (axle) and carefully slide rotor and bearing assembly onto spindle.

9. Slide outer wheel bearing over the spindle and into the recess in the rotor.

10. Tighten the washer and retaining nut onto the spindle to the manufacturer's specifications.

11. Install any spacers and sliders included with the brake caliper per manufacturer's specifications.

12. Drop the new brake caliper (with pads installed) over the disc so that it lines up with the new mounting bracket holes.

13. Install bolts into caliper assembly from the front, after greasing the bolt shafts all along the smooth portion. Torque to manufacturer's specs.

14. Attach brake line to caliper using supplied adapter or new lines. Route lines along factory mounting points, and secure on either end with specialized line wrenches. Do not use a standard wrench, especially when using anodized fittings.

15. Bleed the air out of the brake system after each wheel. After the system is installed, bleed the entire system starting from the first drum replaced and working toward the last.

Tips & Warnings

• Bigger isn't always better. In some cases, larger brakes can actually provide less stopping power than a smaller, vented rotor due to their increased rotational inertia and lower operating temperatures.
• Cars that have rear drum brakes have a proportioning valve built into the system that biases fluid pressure to optimize the original design. A new adjustable proportioning valve is suggested for most applications so that the rear brakes receive the proper amount of fluid pressure.

References

• Classic Performance Products
• CSRP: Disc Brake Swap

Resources

• SSBC Performance Brake Systems