Hydraulic System Junction Block: Service and Repair
JUNCTION BLOCKREMOVAL
1. Disconnect and isolate the negative battery connection at the right front strut tower.
Brake Pedal Holding Tool:
2. Using a brake pedal holding tool such as shown, depress brake pedal past its first 1 inch of travel and secure in this position. This will isolate the master cylinder reservoir from the brake hydraulic system, not allowing the brake fluid to drain out of the reservoir.
3. Remove screw fastening the speed control servo to the upper radiator closure panel.
4. Remove screw fastening the washer filler tube to the upper radiator closure panel.
5. Remove nut and screw securing transmission control module to vehicle.
6. Lift the transmission control module (with speed control servo attached) from its mount leaving its wiring harness attached. Move it off to the side toward the engine making sure not to strain the wires and speed control servo cable.
7. Clean any debris away from the fittings on top of the junction block.
8. Remove the two brake tubes coming from the primary and secondary master cylinder ports at the junction block.
9. Remove the four chassis brake tubes going to each brake, mounted across the front top of the junction block.
10. There are two bolts fastening the junction block and mounting bracket to the engine cradle crossmember. Remove the outboard bolt fastening the mounting bracket to the engine cradle crossmember.
11. Raise the vehicle. See hoisting in Lubrication and Maintenance.
12. Loosen, but do not remove, the remaining mounting bolt fastening the junction block mounting bracket to the engine cradle crossmember.
13. Pivot the junction block and bracket forward on the remaining mounting bolt and remove the junction block and bracket from the vehicle.
INSTALLATION
1. If not already installed, install, but do not tighten, the one bolt in the junction block bracket.
2. Install the junction block with mounting bracket onto the engine cradle crossmember guiding the installed bolt into the slot in the engine cradle crossmember.
3. Align the remaining mounting bolt hole in the junction block bracket with its mounting hole in the engine crossmember and install, but do tighten, the remaining mounting bolt.
4. Tighten the first mounting bolt (installed in engine cradle crossmember slot) to 26 Nm (230 inch lbs.) torque with the aid of a crow foot wrench.
5. Lower the vehicle to the ground.
6. Tighten the remaining junction block bracket to-engine cradle crossmember mounting bolt to 26 Nm (230 inch lbs.) torque.
7. Install the four chassis brake tubes (going to each brake) to the junction block. Tighten the tube fittings to 17 Nm (145 inch lbs.) torque with the aid of a crow foot wrench.
8. Install the two brake tubes coming from the primary and secondary master cylinder ports to the top rear corners of the junction block. Tighten the tube fittings to 17 Nm (145 inch lbs.) torque with the aid of a crow foot wrench.
9. Install the transmission control module (with speed control servo attached) in its normal position. Install the nut and screw securing it in place
10. Install the transmission control module mounting nut and screw securing it in place. Tighten the screw to 6 Nm (45 inch lbs.). Tighten the nut to 12 Nm (107 inch lbs.) torque.
11. Install the screw attaching the washer filler tube to the upper radiator closure panel.
12. Install the screw attaching the speed control servo to the upper radiator closure panel.
13. Remove the brake pedal holding tool.
14. Bleed the base brake system.