- Disc Brake Conversion -
If you have purchased one of the many aftermarket brackets for converting to disc brakes, you can use this information. Besides your brackets you can get these parts at a parts store or an auto salvage.
Brake Rotors:
Buick '68-'72 Century, GS, Regal, Skylark, Special
Chevrolet '69 Camaro, '68-'72 Chevelle, '68-'74 Nova, '70-'72 Monte Carlo
Oldsmobile '68-'72 Cutlass, F85, 442, Vista Cruiser, '73-'74 Omega
Pontiac '69 Firebird, '68-'72 Grand Prix, GTO, Lemans. Tempest, Grand AM; '71-'74 Phoenix, Ventura
GMC '68-'74 Sprint, Caballero
It also uses the stock inner and outer wheel bearings associated with these rotors (Bower/BCA A2 and A6)
Calipers:
Buick '76-'77 Apollo, '73-'76 Skylark, '77 Regal
Oldsmobile '73-'76 Cutlass, '75-'77 Omega
Cadillac '75-'77 Seville
Chevrolet '70-77 Camaro, '73-76 Chevelle, '73-'77 Monte Carlo, '77 Nova, '71-'77 El Camino
Pontiac '70-'77 Firebird, '73-'77 Grand Prix, '75-'77 Ventura
GMC '71-'77 Sprint
1. Remove stock Chevy front brake drums, brakes and backing plates. Clean and inspect spindle for cracks and or damage. Be sure to thoroughly clean out the 5/8 " threaded hole at the top of the spindle- this is extremely important. Use a non-oil base cleaner such as tri-chlorethylene. Clean the threads out with a bottoming tap is necessary - but clean it good.
2. In order to install the inner bearing you must remove .0004" from the spindle inner bearnig seating diameter. This can be accomplished with 240 grit emery paper (or equivalent) and a rotary sanding motion on the spindle. This operation must be continued until the inner bearing can be slid onto the spindle without binding. DO NOT TRY GRINDING OR FILING THE SPINDLE. It only takes a few minutes with emery paper. Note: This procedure must be accomplished on the inner bearing for the 55-57 spindle and on the outer bearing of the 55 spindle only. (Not the 56-57 they are OK as is).
3. Once the bearings have been fitted to the spindle, take the small support bracket (see figure) and install it on the outer surface of the spindle in the two lower holes. Install one of the long (2-3/4") 7/16"-20 bolts through the support bracket, through the rear hole on the spindle and through the stock steering arm. Install the shorter 7/16" -20 bolt (2-1/4") in a similar manner through the front hole. INstall the locknuts supplied in the kit and tighten.
4. Take the appropriate caliper bracket (R/H or L/H as marked on the inside of the bracket) and install it as per the figure, and as follows. Install the 1/2" X 2-1/2" bolt supplied in the kit through the caliper bracket, spacer and support bracket as shown. Install the 1/2" locknut but do not tighten it yet, just snug it up.
5. Take the 5/8" X 1" bolt and install it through the bracket into the spindle. Do not tighten it yet, just snug it up.
6. Take the GM rotor, clean and inspect it as necessary. Install the inner bearing (don't forget grease) followed bu a national #79345 seal. This seal is used on 61-68 Chevy cars without disc brakes. It is readily available at any auto parts store.
7. Install the rotor on the spindle followed by the GM outer bearing. Put the bearing retaining washer and nut on the spindle to hold everything in place temporarily.
8. Turn the rotor on the spindle and check for any interference or minimal clearance between the inside surface of the rotor and the 5/8" upper mount bold. (This is a judgement call - use your own). If you feel additional clearance is required, remove the rotor and bolt, and grind the grade markings off the head of the bolt. (Don't get carried away). Check for adequate clearance on the 1/2" bolt also. Reverse it if necessary.
9. When you have adequate clearance remove the rotor ad the 5/8" bolt from the spindle. Coat the bolt with a few drops of the Loctite solution contained in the kit. Make sure the threads in the spindle are clean. Install the bolt and tighten it and the 1/2" bolt previously installed.
10. Re-check all the bolts for tightness and re-install the rotor and outer bearing. Install the stock 55-57 Chevy bearing retainer washer followed by the special wheel bearing retaining nut supplied in the kit. Don't attempt to use the sock bearing nut - the cotter pin hole won't line up. Adjust the wheel bearings and install the cotter pin. Check for clearance and freedom of rotation once more.
11. Install the brake pads and attaching parts in the caliper and install it on the bracket (remember there is a R/H and L/H caliper) using the standard GM caliper mountig bolts. Tighten bolts to GM recommended torque.
12. Repeat the procedure for the opposite side.
13. Connect the brake calipers to the 55-57 Chevy brake lines using a suitable hose that will allow freedom of suspension and steering travel without interference. Your local auto parts man can help you with this part.
14. Procure a master cylinder of the dual resevoir disc/drum type. (assuming you still have drum type rear brakes). Plumb the master cylinder into the sustem using the appropriate metering/proportioning block from the vehicle from with you obtained the brakes. If you prefer a non-power get a master cylinder from a 70-77 Camaro or equivalent. If you prefer a power set-up get the appropriate booster and plumbing. Whatever method you use, DON'T attempt to use the 55-57 cylinder - it won't work.
15. Fill the system with a suitable brake fluid, bleed it, and check for leaks.
- MASTER CYLINDER INSTALLATION -
(Non-Power Assisted)
Install the master cylinder on the two lower mounting studs used for the stock master cylinder (it bolts right on). Shorten the pushrod and re-install. Don't forget the rubber boot - it keeps the rod in the master cylinder. Put the two nuts back on the top two mounting studs and connect the brake lines as noted.
- 55-57 CHEVY MODIFICATION SWAPS -
1. Take a set of spindles from a '68-'72 Chevelle, Monte Carlo, or Grand Prix. swap sides and bolt to the sock a-arms of a '55-'57 Chevy and you have easy disc brakes.
2. Find a '75 Monza and borrow it's power brake booster as it will bolt right into your shoe box without modification.
3. A Saginaw steering box from a '75 International Harvester truck will bolt right up to your '55-'57 and can be had for a fraction or the normal price.
4. A Chevelle 12-bolt rear end can be adapted to fit Tri-5's by welding on Moroso spring plates.
5. You can also use a Chevelle trans cross member on a tri-5 by trimming the ends to fit the frame rails. Then flatten the ends and drill new mounting holes.
6. I have also heard that the master cylinder from a S-10 pickup will bolt onthe the shoeboxes. I haven't tried it, so I can't confirm if it works or not.