Showstopper - Technical Article - Chevy High Performance Magazine

Adding a Master Power Disc Brake Kit

Bob Mehlhoff May 1, 2006 0 Comment(s)

Today's vintage musclecar packs more power, is driven faster, and most of all, is asked to stop a whole lot quicker than 40 years ago. And as retro as those drums may look through your mag wheels, the original brake system can't be counted on to stop quickly should trouble arise. In other words, a decrease in stopping distance can mean the difference between a close call or some crumbled Chevy fenders.

However, there is good news. Master Power Brakes has a disc brake kit (available for all popular GM musclecars) that can convert your ride from those low-performing and slow-stopping drums to a stop-on-a-dime, four-wheel disc-brake dancer that rivals many new-car braking standards. The kit comes with easy-to-follow instructions and a handy tech line to call, if needed. To see how this installation works, we used a '65 Chevrolet Biscayne that still wore the factory four-wheel drum system. Master Power offers several kits for this application. For ours we chose three of the options, including a front disc brake conversion kit that bolts to the existing drum spindles, a power-operated tandem master cylinder kit complete with the proper proportioning valve, and a rear disc brake kit that bolts on to the stock rearend housing. If you opt to use the GM rear disc brake rotors, you'll need to have your axle flanges turned down to 5 7/8-inch o.d. to gain the needed clearance inside the hub of the new rotors. If you have aftermarket hardened axles, check with the axle manufacturer first.

Whether you own a full-size Chevrolet, Chevelle, Camaro, Nova, or other GM car, chances are there is a Master Power Brakes kit available for your specific application. Hang on as we show you the ins and outs of adding a power four-wheel disc brake system onto our lead-sled Biscayne. We just hope the T3 headlights won't fly out when we hit those new disc brakes hard.

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The kit we selected for the front of our '65 Biscayne came complete with new disc brake rotors, calipers, adapter brackets, a power brake booster, the master cylinder, including the combination valve with new steel lines, wheel bearings, and hoses.

The stock drum brake setup didn't stop our 2-ton big-block-powered B-body very well. The addition of disc brakes will be a welcome relief, especially during unexpected brake-test sessions.

The stock drum brake hardware, hubs, and backing plates were easily removed. Before we started our install, we measured the wheel-mounting height location on the drum brake hub and compared it to that of the new disc brake hub. We found that the disc brake wheel-mounting position widens the front wheel track 1 inch on each side. To compensate for this, you may want to install the appropriate wheel or tire size to complement the disc brakes and to ensure your tires won't rub.

Next we unbolted the drum brake backing plates from the spindles and disconnected the stock hoses from the steel lines.

Then we attached the two front brake caliper brackets...

...and found the larger bracket required the lower inside mounting hole to be reamed out slightly (shown left; original-size hole on right) to allow the bracket to clearance the spindle on its forward lower side. The entire operation took roughly 15 minutes for both brackets.

Finally we tightened everything in place. Double-check the directions to ensure proper torque is applied onto all bolts and nuts.

The new brake rotor is then fitted with new wheel bearings, which we packed with grease, followed by a new inner seal. After the rotor is installed onto the spindle, we spun the rotor while tightening the spindle nut several times. We then backed off the nut just to the next available slot and installed a new cotter key and grease cap. When the rotor is installed properly, there should be a very small amount of endplay felt when the rotor is pushed and pulled laterally on the vehicle.

Next we loaded the front calipers with the new brake pads, slipped them into position, slid the caliper over the rotor onto the mounting holes, and bolted them in place. From there we installed the new brake hoses with the appropriate copper washers.

Before we installed the front wheels, we made one final inspection for clearance, rotor rotation, and did a once-over on the brake-line installation.

We then remounted the front wheels and put the car back on the ground. Remember that with the new rotors in place, the wheel mounting positions are moved out 1 inch per side. So make sure you'll have enough tire to fender clearance with the car settled on the ground. If not, different-size tires or rims will give you the necessary clearance.

Our front disc brake kit came with a power brake unit, master cylinder, combination valve, fittings, and metal lines. Since less vacuum will cause a hard pedal, your engine should ideally be able to produce 18 inches of manifold vacuum at idle in Park. Anything less, and you may want to opt for the manual disc kit or install an electric vacuum pump, which is also available from MPB.

We first removed the stock single reservoir master, metal line, and power brake booster.

Then we disconnected the stock clevis from the brake pedal and drilled a 3/8-inch hole 1 inch below the original.

Tech Tip
If you are using Cadillac Eldorado-style rear calipers (as we did), there are some important things you should know. These rear calipers adjust off the parking brake, which is incorporated into the caliper. You must set the parking brake every time you park the car so that you utilize a one-way clutch inside the caliper piston. When the parking brake is applied, the clutch senses when there is a 0.030-inch or greater clearance between the friction material and the rotor on the inboard side. When there is in excess of 0.030 inch, the clutch turns inside the piston, adjusting it out, keeping the rear brakes adjusted. If you do not set your parking brake every time, you will start to lose brake pedal (low and spongy) and the adjuster mechanism will not work.

Sources

Master Power Brakes
Mooresville, NC 28117
888-351-8785
http://www.mpbrakes.com
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