Pickup 2WD L4-2466cc DSL (1984) Power Brake Assist Service
Vacuum Pump: Service and Repair
VACUUM PUMP
REPLACE
1. Disconnect battery ground cable.
2. Disconnect vacuum hoses from pump, then the oil outlet hose.
3. Remove three vacuum pump attaching screws, then the pump.
4. Remove O-ring from alternator end frame.
5. Reverse procedure to install. Torque attaching bolts to 69 inch lbs.
DISASSEMBLY
1. Remove vacuum hose union and check valve from pump.
2. On Pickup, tip pin downward, then remove end plate.
3. On models except Pickup, remove oil outlet hose union.
4. Using a suitable drift, drive out pin punch, then remove end plate.
5. On all models, remove O-ring, then the rotor and blades.
INSPECTION
1. Check blades for wear and damage.
2. Check rotor blades for proper height thickness and length. Minimum height should be 0.524 inch, minimum thickness should be 0.2343 inch and
minimum length should be 0.9047 inch. If blade dimensions are not as specified, replace blades.
3. Inspect rotor and shaft for wear and damage.
4. On models exc. Pickup, measure clearance between rotor and shaft. Clearance should be 0.035 inch. If damage is present or clearance is not as
specified, replace rotor and/or shaft as necessary.
5. Ensure air flows from hose side to pump side of check valve, but will not flow in reverse direction. Replace as necessary.
6. Check bushing and oil seal for wear and damage. Replace end frame assembly as necessary.
ASSEMBLY
1. Install rotor into casing, then insert blades with round end facing outward. Ensure rotor and blade surfaces are flush.
2. Install new O-ring into groove of casing, then assemble end plate to casing.
3. Align pin holes of casing and end plate, then drive in pin until 0.12 inch above surface.
4. On models except Pickup, install oil outlet union with union bolt and new gasket. Torque union bolt to 24 ft. lbs.
5. On all models, install check valve with new gasket, then torque to 54 ft. lbs.
6. Install vacuum hose union with union pipe and new gaskets, then torque to 9 ft. lbs.
