REMOVAL & INSTALLATION
See Figures 1, 2, 3, and 4
- Disconnect the negative battery cable.
- Disengage the low fluid level sensor connector.
- Disengage the lines from the master cylinder connections. Cap the brake lines and plug the master cylinder ports.
- Loosen the two master cylinder retaining nuts and washers.
- Remove the master cylinder from the vehicle.
If a new master cylinder is being installed, check the pushrod length adjustment as follows:
- Position master cylinder gauge T87C-2500-A or equivalent on the end of the master cylinder, loosen the setscrew and push the gauge plunger against the bottom of the primary piston.
- While holding the gauge in position, tighten the setscrew.
- Invert the master cylinder gauge and place it over the brake booster pushrod.
- If the clearance is not zero, loosen the pushrod locknut and adjust the pushrod.Proper pushrod length adjustment is critical. If the pushrod length is too long, the brakes will drag. If the pushrod length is too short, the brake pedal will be low.
Before installation, bench bleed a new master cylinder as follows:
- Mount the new master cylinder in a suitable holding fixture. Be careful not to damage the housing.
- Fit short lengths of brake lines to the master cylinder ports, so that they are directed into the master cylinder reservoir and submerged by brake fluid.
- Fill the master cylinder reservoir with clean DOT 3 or equivalent brake fluid.
- Using a suitable tool inserted into the booster pushrod cavity, push the master cylinder piston in slowly and allow it to return.
- Repeat the procedure until clear fluid only (no bubbles) is expelled into the master cylinder reservoir.
- Remove the short brake lines and plug the outlet ports. Remove the master cylinder from the holding fixture.
- Position the master cylinder and install the attaching washers and nuts. Tighten the nuts to 7-12 ft. lbs. (10-16 Nm).
- Connect the brake lines to the master cylinder ports and tighten.
- Have an assistant push down on the brake pedal.
- When the pedal is all the way down, crack open the brake line fittings at the master cylinder, one at a time, to expel any remaining air at the master cylinder.
- With the pedal still down, tighten the brake line fitting, then allow the brake pedal to return.
- Repeat until all air is expelled. Final-tighten the brake line fittings to 10-15 ft. lbs. (13-21 Nm).
- Bleed the brake system.
- Connect the low fluid level sensor.
- Make sure the master cylinder reservoir is full.
- Connect the negative battery cable.
- Check for leaks and proper brake operation.