nstalling 12" brakes on a Second Generation GM F-Body.
By Steve Chin
Revised: November 1, 2005
Thanks to Steve Robertson for C&C. Second generation (Gen2) Firebirds are great handling cars, especially with upgrades. If the engine in the car has been treated to perfrormance-enhancing modifications, or if the car is used in autocrossing or road-racing, better stopping power is necessary. The factory 4-wheel disc setup (available 1979-1981) was a step in the right direction. Another modification that can be performed is the installation of larger front brakes. This modification can be performed on cars with or without rear disc brakes, but pest performance is realized when the car is also equipped with rear disc brakes. This article outlines how to install 12" front brakes using all factory parts.
Components necessary for the swap:
2 - Front Brake Rotor, with studs and bearing seats, 1987 Firebird (Formula or Trans Am) 1LE
1 - Left Front Spindle, 1977-1983 GM B-body with heavy-duty brakes
1 - Right Front Spindle, 1977-1983 GM B-body with heavy-duty brakes
1 - Left Splash Shield, 1977-1983 GM B-body with heavy-duty brakes
1 - Right Splash Shield, 1977-1983 GM B-body with heavy-duty brakes
4 - 2" Cotter Pins
4 - 2.75" Cotter Pins
2 - Inner Front Wheel Bearing Seal, 1987 Firebird 1LE (same as for 1970-1/2-1981 Firebird)
1 - Disc Brake Pads, Set, 1987 Firebird 1LE (same as for 1970-1/2-1981 Firebird)
A/R - Disc Brake-Compatible Wheel Bearing Grease
A/R - DOT 3/4/5 Approved Brake Fluid (use a high-quality fluid)
A/R - Brake Cleaning Solvent
Components that are nice for the swap, but not totally necessary:
2 - Front Wheel Bearing, Inner, 1987 Firebird 1LE (same as for 1970-1/2-1981 Firebird)
2 - Front Wheel Bearing, Outer, 1987 Firebird 1LE (same as for 1978-1981 Firebird, required on cars that do not have the large outer wheel bearing)
4 - Bolt, Front Caliper Retaining, 1977-1983 GM B-Body (same as for 1970-1/2-1981 Firebird)
1 - Hose, Front Brake Pressure, Set, 1970-1/2-1981 Firebird
2 - Caliper, Front Brake, 1970-1/2-1981 Firebird (or rebuild kits for existing calipers)
2 - Ball Joint, Upper, 1970-1/2-1981 Firebird
2 - Ball Joint, Lower, 1970-1/2-1981 Firebird
2 - Tie Rod End, Outer, 1970-1/2-1981 Firebird
1. The Gen3 Firebird/Camaro uses metric wheel studs. They are 12mm in diameter with a 1.50mm thread pitch. You will need lug nuts to fit this pitch and your wheels.
2. Alternatively, you can press out the pre-installed studs in your rotors, machine the stud openings for compatibility with American-sized studs (7/16"-20 is standard on the Gen2 Firebird/Camaro), and press in new 7/16"-20 studs.
3. Splash shield styles vary a bit from year to year. The bolt hole locations seem to all be in the same positions in all Gen2 Firebirds and Camaros. The bolt pattern of the splash shields on the B-body spindles is also the same. You can use either the splash shields that came with your car or the ones that came with the spindles.
4. When inserting cotter pins into ball joint and tie rod end nuts, NEVER back the nut off from its initial torque setting. If necessary, tighten the nut up to 1/6 of a revolution in order to line the castellations in the nut up with the hole in the stud.
Remove The Original Parts:
1. Park car on flat, level surface. Block the rear wheels and set the parking brake. Remove top from brake master cylinder. Using a suitable tool, remove half of the fluid from the front reservoir. Place fluid in a suitable container for recycling. Replace top on master cylinder, but do not flip bail to secure the top.
2. Loosen lug nuts on front wheels. Jack car up and support using car stands. Ensure that car is securely placed on stands. Remove lug nuts and front tires, remembering which tire was installed where. I usually mark the tread of the left front tire with a piece of masking tape so that I know the one with masking tape goes on the left side.
3. If you are going to replace or rebuild the front brake calipers, place a suitable drip catching container under the brake caliper and disconnect the pressure supply hose. Remove pressure supply hose if you are going to replace it. After system has finished draining, place fluid in a suitable container for recycling. Unbolt brake caliper and remove. If you are not rebuilding or replacing the caliper or are not replacing the pressure supply hose, suspend caliper with a suitable fixture so that it does not place any tension on its pressure supply hose.
4. Remove dust cap from center of brake rotor. Remove cotter pin from nut retainer/spindle and discard. Remove spindle nut. Remove wheel bearing washer. Clean nut and washer and place where they won't get lost. Remove the front rotor from the spindle.
5. It is recommended that the front wheel bearings be replaced during this modification. If you are replacing the front wheel bearings, skip this series of steps. Remove the wheel bearings from the hub of the rotor. Discard the wheel bearing seal. Clean bearings thoroughly with a suitable solvent. Blow all traces of solvent out of bearings using compressed air. Place bearings in a clean place and allow to air-dry.
6. Remove cotter pins from upper and lower ball joint retaining nuts and discard. Remove cotter pin from outer tie rod end retaining nut and discard. Using a suitable tool (I prefer to use a tie rod press over a picklefork), separate the tie rod end from steering knuckle. Support lower control arm at the spring pocket using floor jack (do NOT raise jack any more than is required to just contact the lower control arm and apply just the slightest amount of pressure to the control arm). Unscrew the upper and lower ball joint retaining nuts and place where they will not get lost. Support the spindle assembly (it is heavy - don't let it fall on you!). Using a suitable tool (again, I prefer to use a press to a picklefork), separate the lower ball joint from the spindle upright. Lift the upper control arm a little away fron the spindle assembly. Using a suitable tool, separate the upper ball joint from the spindle upright. Remove spindle and discard.
7. It is recommended that the ball joints and tie rod ends be replaced at this time. The procedures for replacing these parts can be found in the Factory Shop Manual.
Install The Replacement Parts:
8. Position B-body spindle upright over lower ball joint and place it on the ball joint stud. Install lower ball joint nut. Position top of spindle upright under upper ball joint stud and insert stud into hole in top of spindle upright. Install upper ball joint nut. You will probably need to adjust the height of the floor jack in order to get the ball joint studs to insert far enough into the B-body upright. Torque lower ball joint nut to 83 lb./ft. and install cotter pin. If hole in ball joint stud does not align well with castellations in nut, tighten nut until cotter pin will fit, but do not exceed 95 lb./ft. of torque. Torque upper ball joint nut to 64 lb./ft. and install cotter pin. If hole in ball joint stud does not align well with castellations in nut, tighten nut until cotter pin will fit, but do not exceed 72 lb./ft. of torque. Rotate spindle so that steering knuckle aligns with tie rod end stud. Insert tie rod end stud into hole in steering knuckle and install tie rod end nut. Torque tie rod end nut to 35 lb./ft. and install cotter pin. If hole in ball joint stud does not align well with castellations in nut, tighten nut until cotter pin will fit, but do not exceed 50 lb./ft. of torque. Remove floor jack from its support position under the control arm. If splash shield is not already installed on spindle, install it and torque retaining bolts to 15 lb./ft. Lower and remove jack from under lower control arm.
9. Wash hands. Place rotor so that its inner bearing race is facing up. Pack wheel bearings with high-quality disc brake-compatible wheel bearing grease. Pack inner bearing race with grease and line cavity with a moderately thick layer of grease. Place inner bearing into the inner race on the new rotor. Install new inner wheel bearing seal using a suitable seal driver. Flip rotor over and pack outer bearing race and cavity around outer race with grease. Place outer bearing into the outer race.
10. Position rotor over spindle. Slide rotor/bearing assembly onto spindle, making sure that both bearings stay seated in their races. When rotor/bearing assembly is seated fully on spindle, install wheel bearing washer onto spindle, then install spindle nut onto spindle making the nut "finger tight." While rotating rotor, torque retaining nut to 20 lb./ft. then back off and finger tighten the retaining nut. If the castellations on the spindle nut do not align with the hole in the spindle, rotate the rotor and tighten the nut until the castellations and holes align, then install the cotter pin. Install bearing dust cap.
11. Wash hands. Wash rotor with solvent to ensure that the surface is not contaminated. Ensure that piston is fully compressed into brake caliper. Discard old brake pads. Install new brake pads into caliper. Install caliper on spindle. Insert retaining bolts and torque to 35 lb./ft.
12. If you are installing new brake hoses and/or calipers, install the brake hoses onto the brake lines at the frame first, then onto the caliper.
13. Repeat steps 3 through 12 on the other side of the vehicle.
14. Partially fill front brake reservoir. Bleed brakes, passenger side first. This will require refilling the master cylinder reservoir at least once. Reinstall tires onto car. Install lug nuts finger-tight. Examine alignment of front tires - they will probalby be toed in heavily. Loosen the tie rod sleeve clamps and lubricate the tie rod sleeves with a good penetrating oil. adjust the tie rod sleeves to approximate the original toe-in (generally, adjusting the sleeves equally 2-7/8 turns so that they toe the tires out is close enough to get you to the alignment shop without destroying the front tires). Lift car with floor jack and remove car stands. Lower car until part of its weight is supported by the jack and part by the tires. Torque lug nuts to 75 lb./ft. Lower car to rest on ground. Drive slowly and carefully to a competent alignment shop and have the front end aligned. A good baseline alignment would be 1/16" toe-in, 1 degree negative camber, 1 degree positive caster. Enjoy!
Disclaimer: Some of the operations and situations noted in these articles may lead to dangerous or hazardous conditions. I take no responsibility for anything you do as a result of seeing these articles. The information presented herein is intended strictly for informational and entertainment purposes only.
Copyright 1998 Steven Chin. None of the material presented on this site may be reproduced without the express consent of its' copyright holder.