Caterpillar 3512B Generator Set

1. Remove the drive belt guard.
2. Loosen mounting bolt (1), adjusting nuts (2) and mounting bolt (3).
3. Turn adjusting nuts (2) to increase or decrease drive belt tension.
4. Tighten adjusting nuts (2), mounting bolt (3), and mounting bolt (1).
5. Reinstall the drive belt guard.
6. If new belts installed, recheck tension after 30 minutes at rated rpm.

⚠ High voltage can cause electrocution. Discharge instrument leads and generator windings.

Tools: 300-8648 Insulation Testing Gp

1. Take the generator out of service.
2. Visually inspect generator for moisture. If moisture exists, dry the unit first.
3. Inspect installation. Determine equipment that will be tested.
4. Discharge capacitance of the windings. Disconnect 'T0' from ground.
5. Disconnect sensing lead wires for regulator and PT leads of load share module.
6. Connect insulation tester Black lead to ground; RED lead to 'T0'.
7. Set voltage to rated voltage. Apply voltage; observe readings at 30 and 60 seconds.
8. Record 60 second reading (correct for temperature), temperature, and humidity.

⚠ Batteries give off combustible gases which can explode; ensure proper ventilation.

⚠ Always recycle a battery; never discard a battery.

1. Turn key start switch OFF. Remove key and all electrical loads.
2. Turn OFF battery charger. Disconnect the charger.
3. Disconnect NEGATIVE '-' cable from NEGATIVE battery terminal.
4. Disconnect POSITIVE '+' cable from POSITIVE battery terminal.
5. Remove the used battery. Install the new battery.
6. Connect starting motor cable to POSITIVE '+' battery terminal.
7. Connect ground plane cable to NEGATIVE '-' battery terminal.

⚠ In dusty applications, more frequent cleaning is required.

1. Remove wing nut (1) and cover (2).
2. Check for accumulation of dirt and debris in body (3). Clean the body, if necessary.
3. After cleaning the precleaner, install cover (2) and wing nut (1).

⚠ Do not attempt to disassemble the breathers.

1. Loosen clamp (1). Slide the clamp down on tube (2).
2. Loosen clamps (3). Remove both breathers as a unit.
3. Remove O-ring seals (4) from valve covers. Inspect; obtain new seals if necessary.
4. Remove two clamps (6). Remove both breathers (5) from hose tee (7). Inspect tee for cracks.
5. Turn breathers upside-down. Clean breather elements with clean, nonflammable solvent.
6. Allow breather elements to dry before installation. Do not disassemble breathers.
7. Install breathers into tee; tighten clamps to the torque in Service Manual, Specifications.
8. Coat O-ring seals with clean engine oil; install and tighten clamps.

⚠ Hot oil and components can cause personal injury.

⚠ Parts and covers are under spring pressure.

Tools: Utility knife (inspect used filter)

1. After operating at normal temperature, STOP the engine. Drain the warm oil.
2. Open oil drain; after oil has drained, close the oil drain.
3. Gradually loosen but do not remove bolts (4); pry cover (5) loose to relieve spring pressure.
4. Remove cover and O-ring seal. Clean cover, seal, and inside of oil filter housing.
5. Install new oil filter elements. Install new O-ring seal if damaged.
6. Install cover (5); ensure springs are seated properly.
7. Fill crankcase through oil filler tube only. Clean and install oil filler cap.
8. Close fuel supply; crank until oil pressure gauge indicates 70 kPa (10 psi).

⚠ In hot, dirty, or humid environments lubricate the fan bearings more frequently.

Tools: Grease gun

1. Inspect the fan drive pulley assembly. If shaft is loose, inspect internal components.
2. Lubricate the grease fittings for the fan bearings with Bearing Lubricant or equivalent grease.

⚠ Enable the starting system only after all maintenance has been completed.

1. Open the fuel supply valve. Ensure engine will not start. Turn start switch OFF.
2. Turn fuel priming pump plunger counterclockwise to release lock plate from retainer.
3. Operate the fuel priming pump until air is pumped through return line to fuel tank.
4. Press plunger to locking position. Turn plunger clockwise to engage lock plate.

⚠ Fuel leaked or spilled onto hot surfaces can cause a fire.

⚠ Do not fill fuel filters with fuel before installing.

1. Stop the engine. Ensure engine will not start. Shut off fuel supply valve.
2. Loosen nut (2). Hold filter case (1) and remove nut (2). Catch fuel in a container.
3. Remove element and wash it in clean, nonflammable solvent. Allow to dry. Inspect.
4. Clean inside of filter case. Allow to dry.
5. Inspect O-ring seals; obtain new seal rings if damaged. Install seals.
6. Place element in filter case. Slide filter case over mounting bolt.
7. Install nut. Open fuel supply valve.
8. Prime the fuel system.

⚠ Do not mix greases.

Tools: Grease fitting

1. Remove louver assembly or rear plate from rear of generator housing.
2. Remove the top grease pipe plug and the lower grease pipe plug.
3. Install a grease fitting in the grease pipe.
4. Grease the bearings with the appropriate grease from Table 44. Do not mix greases.
5. Wipe off excess grease. Remove top grease fitting. Install the plug.
6. Operate generator one hour; grease expands and excess purges from cavity.
7. Stop engine. Install plug in bottom grease pipe. Wipe off excess grease.
8. Install louver assembly or rear plate.

⚠ Do not continue engine operation if turbocharger bearing failure causes performance loss.

Tools: Dial indicator, Soft bristle brush

1. Remove exhaust outlet piping and air inlet piping. Inspect piping for oil; clean interiors.
2. Turn compressor wheel and turbine wheel by hand; assembly should turn freely.
3. Inspect wheels for contact with turbocharger housing; recondition if contact found.
4. Check compressor wheel for cleanliness; oil on back side suggests failed oil seal.
5. Use a dial indicator to check end clearance on the shaft.
6. Inspect bore of turbine housing for corrosion.
7. Clean turbocharger housing with standard shop solvents and a soft bristle brush.
8. Fasten air inlet piping and exhaust outlet piping to turbocharger housing.

⚠ Do not start the engine. Ensure engine control is in OFF position.

1. Do not start engine. Ensure engine control is OFF. Latch both air shutoff gates OPEN.
2. Turn ON engine control panel power; gates should remain open.
3. Activate EMERGENCY STOP switch; both air shutoff gates should close.
4. Reset switch to RUN. Latch only right side gate OPEN; turn power ON; right gate should close.
5. Turn power OFF. Latch only left side gate OPEN; turn power ON; left gate should close.
6. Testing complete only when engine passes steps 1 through 4.
7. Operate engine normally; ensure air shutoff gates remain latched.