How to Check the Brake Booster in a 1986 Ford Ranger

Ford used a brake booster in the 1986 Ranger to reduce brake pedal effort and increase power to the hydraulic brake system. Brake boosters require no special maintenance other than periodic checks for case damage or leaks in the vacuum hose. Damage to the internal diaphragm, valve or return spring cannot be repaired, and the booster must be replaced as a unit if such damage is present. Brake drag or excessive brake pedal travel accompanied by a groaning sound from the booster when the brakes are actuated are indicative of a maladjusted booster pushrod.

Instructions

Inspection and Adjustment

1

Inspect the booster case for signs of obvious damage. Breaks or holes in the booster case prevent the booster from properly operating.

2

Inspect the engine vacuum hose for breaks, leaks or kinks that may affect the vacuum powering the brake booster. Replace the hose as necessary.

3

Remove the two nuts holding the master cylinder onto the brake booster studs using a ratchet and deep socket. Carefully pull the master cylinder away from the booster until it comes free of the booster studs. Do not break or kink the brake lines attached to the master cylinder during this process.

4

Measure the protrusion of the brake rod using a machinists rule. Keeping the machinists rule parallel to the brake rod, and measure from the tip of the rod to the brake booster case where the studs exit the case

5

Adjust the rod until the protrusion is between 0.980 to 0.995 inches, using a wrench.

6

Install the master cylinder onto the brake booster studs. Install the two nuts onto the studs and tighten them to 13 to 25 foot-pounds using a torque wrench and deep socket.

Booster Removal

7

Remove the two nuts holding the master cylinder onto the brake booster studs, using a ratchet and deep socket. Carefully pull the master cylinder away from the booster until it comes free of the booster studs. Do not break or kink the brake lines attached to the master cylinder during this process.

8

Loosen the clamp on the vacuum hose where it connects to the brake booster, using a screwdriver. Remove the vacuum hose from the brake booster.

9

Locate the brake linkage and brake light switch inside the passenger compartment on the upper end of the brake pedal.

10

Disconnect the electrical connector from the brake light switch.

11

Remove the cotter pin from the end of the brake pedal stud, using needle-nose pliers. Slide the brake light switch, brake booster pushrod and spacers off the stud.

12

Locate the two brake booster mounting studs coming through the firewall near the brake booster pushrod inside the passenger compartment. Remove the nuts from the studs using a ratchet and deep socket.

13

Pull the brake booster away from the firewall and lift it out of the engine compartment.

Booster Installation

14

Measure the protrusion of the brake rod on the new booster using a machinists rule. Keeping the machinist's rule parallel to the brake rod, and measure from the tip of the rod to the brake booster case where the studs exit the case.

15

Adjust the rod until the protrusion is between 0.980 to 0.995 inches, using a wrench.

16

Align the new brake booster and mounting studs with the holes in the engine compartment firewall and push it into place.

17

Install the nuts onto the brake booster mounting studs inside the passenger compartment and tighten them to 13 to 25 foot-pounds using a torque wrench and deep socket.

18

Slide the spacers, booster pushrod and brake light switch onto the brake pedal stud. Install the cotter pin in the stud, using needle-nose pliers.

19

Install the brake booster vacuum hose onto the booster and tighten the vacuum hose clamp, using a screwdriver.

20

Install the master cylinder onto the brake booster studs. Install the two nuts onto the studs and tighten them to 13 to 25 foot-pounds using a torque wrench and deep socket.