777G Off-Highway Truck Automatic Lubrication System (Type A1) Caterpillar

A problem must be identified and the problem must be defined before the problem can be corrected. When the problem is identified and the problem is defined proceed to the "Performance Checks" section. The following procedure should be used in order to help identify the problem. Also, use the following procedure in order to define the problem.

1. Perform visual checks in order to help identify the problem.

2. Check within "Performance Checks" in order to help identify the problem.

3. Perform operation checks which are related to the problem.

Performance Checks

Illustration 1	g01262277
Automatic lubrication pump (1) Autolube pump motor (2) Autolube solenoid valve (3) Electric vent valve

Illustration 2	g01262279
View A-A (4) Outlet check valve (5) Safety unloader valve (6) Lubricant reservoir

Problem: No lubricant at the bearing.

Probable Cause

• Broken lube line or restricted lube line

• Lubricant reservoir (6) is empty.

• The lubricant injector is malfunctioning.

• The lubricant pump is malfunctioning.

Problem: Lubricant is leaking from the safety unloader valve.

Probable Cause

• The pressure of the system is set too high.

• Safety unloader valve (5) is damaged or contaminated.

Problem: The pump does not operate.

Probable Cause

• There is no electrical power to the pump.

• The motor relay failed.

• Autolube solenoid valve (2) failed.

• Autolube pump motor (1) overheated.

• Autolube pump motor (1) tripped out on locked rotor protection.

• The shaft is broken.

• Gears are broken.

• The fuse is blown.

• Autolube pump motor (1) polarity is reversed.

Problem: The pump runs excessively.

Probable Cause

• The pump tube malfunctioned.

• Outlet check valve (4) is damaged or contaminated.

• Vent valve (3) is damaged or contaminated.

• A system component is leaking.

• There is injector bypassing.

Problem: The pump speeds up or runs erratically.

Probable Cause

• There is a low level of grease.

• Lubricant reservoir (6) is empty.

• The follower plate is stuck and separated from the grease.

• The pump piston is worn.

• The check valves are worn.

Problem: The pump runs, but the output is low.

Probable Cause

• The motor speed control is set too low.

• There is a faulty inlet or discharge check valve in the pump.