REMOVAL & INSTALLATION Jeepster/Commando
See Figure 1
Fig. Fig. 1: Cross-sectional view of the power booster used on the Jeepster/Commando models
- Remove all dirt from the master cylinder and booster.
- Disconnect the pushrod from the pedal linkage.
- Remove the vacuum hose from the check valve.
- Disconnect the brake light switch wires from the switch.
- Disconnect the hydraulic lines at the master cylinder.
- Unbolt the booster from the firewall and remove the booster and master cylinder as a unit.
- Installation is the reverse of removal. Prior to installation, check the pushrod height. The pushrod should protrude 0.980-.0.995 in. above the booster surface. It has a built-in adjusting screw to regulate the protrusion.
- Bleed the brakes.
1962-69 Wagoneer and J-Series Truck
Vehicles during these years were equipped with either a Bendix (vehicles with automatic transmission) or Midland-Ross (vehicles with manual transmission) system. The Bendix system gives a low, wide pedal; the Midland system gives a low, wide pedal; the Midland system gives a high pedal to be compatible with the clutch pedal.
BENDIX SYSTEM
See Figures 2, 3 and 4
Fig. Fig. 2: Diagram on how to fabricate a tool to measure Bendix booster pushrod height
Fig. Fig. 3: Component location on the Bendix brake booster 1962-69 Wagoneer and J-series truck models
Fig. Fig. 4: Checking Bendix pushrod height with a gauge
- Remove all dirt from the master cylinder and booster.
- Disconnect the pushrod from the pedal arm.
- Remove the vacuum hose from the check valve.
- Disconnect the hydraulic lines at the master cylinder.
- Unbolt the booster from the firewall and remove the booster and master cylinder as a unit.
- Installation is the reverse of removal. Prior to installation, check the pushrod height. The pushrod should protrude 1.245-1.250 inches above the booster surface. It has a built-in adjusting screw to regulate the protrusion.
- Bleed the brakes.
See Figures 5 and 6
Fig. Fig. 5: Midland-Ross brake booster used on 1962-69 Wagoneer and J-series truck models
Fig. Fig. 6: Measuring Midland-Ross booster pushrod height with a gauge
- Disconnect the master cylinder and wheel cylinder hydraulic lines from the slave cylinder.
- Disconnect the vacuum hose from the check valve.
- Remove the mounting bracket-to-slave cylinder attaching screws and lift the booster from the truck.
Installation is the reverse of removal. Check pushrod height with the gauge illustrated. Fill and bleed the system.
1970-86 Models
See Figures 7 and 8
Fig. Fig. 7: Cross-sectional view of a single diaphragm power booster used on all 1970-77 Wagoneer, Cherokee and J-series truck models and 1978-83 Wagoneer, Cherokee and J-10 models
Fig. Fig. 8: Dual diaphragm power brake booster used on all 1978-83 J-series truck models
- Disconnect the power unit pushrod at the pedal.
- Disconnect the vacuum line at the power unit check valve.
- Unbolt the master cylinder from the power unit and move it out of the way without disconnecting the brake lines. Be careful to avoid kinking the lines!
- Unbolt and remove the power unit from the firewall.
- Installation is the reverse of removal. Torque the power unit-to-firewall nuts to 30-35 ft. lb.; the master cylinder-to-booster nuts to 25-30 ft. lb.
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