ACTUATOR GP-BRAKE 8W8355 - Caterpillar

Probable Causes
Contaminated oil
Leaks in air intake system
Engine History
Low oil pressure
Dirt in engine oil
Incorrect oil
Dirt in fuelRecommended Actions
Note: The procedures have been listed in order of probability. Complete the procedures in order.
Table 1
Troubleshooting Test Steps Values Results
1. Contaminated Oil
A. Check an oil sample for contamination with fuel. Refer to Troubleshooting, "Oil Contains Fuel".
Oil contains fuel
Result: The engine oil is contaminated with fuel.
Repair: Investigate the cause. Refer to Troubleshooting, "Oil Contains Fuel".
Result: The engine oil is not contaminated with fuel.
Proceed to Test Step 2.
2. Leaks in Air Intake System
A leak in the air intake system may allow unfiltered air into the engine.
A. Inspect the air intake system for streaks which may indicate a leakage of unfiltered air. Inspect all of the gaskets and the connections. Refer to Systems Operation, Testing, and Adjusting, "Air Inlet and Exhaust System".
Leaks in Air Intake System
Result: Leaks found in air intake system.
Repair: Repair any leaks.
Result: The air intake system is OK.
Proceed to Test Step 3.
3. Engine History
A. Check that the engine has been serviced to the correct maintenance intervals. Refer to Operation and Maintenance Manual, "Maintenance Interval Schedule"
B. Check the engine history for frequent starting and stopping in cold conditions.
Note: Frequent starting and stopping of the engine can cause early wear. Also, operation of the engine for short periods of time in cold conditions can cause early wear.
Maintenance intervals
Result: The engine is not correctly maintained.
Repair: Make sure that the engine is maintained at the correct maintenance intervals. Refer to the Operation and Maintenance Manual, "Maintenance Interval Schedule".
Result: The engine is correctly maintained.
Proceed to Test Step 4.
4. Low Oil Pressure
A. Check for frequently logged diagnostic codes relating to low oil pressure.
Low oil pressure
Result: The engine has a history of low oil pressure.
Repair: Refer to Troubleshooting, "Oil Pressure Is Low".
Result: There are no logged diagnostic codes for low oil pressure.
Proceed to Test Step 5.
5. Dirt in Engine Oil
A. Check the engine oil for dirt or debris.
Dirt in engine oil
Result: The engine oil shows signs of dirt or debris
Repair: Drain the oil from the crankcase and refill the crankcase with clean engine oil. Install new engine oil filters. Refer to the Operation and Maintenance Manual for more information.
Result: The engine oil is clean.
Proceed to Test Step 6.
6. Incorrect Oil
A. Check that the engine is filled with oil of the correct specification. Refer to the Operation and Maintenance Manual, "Refill Capacities and Recommendations".
Oil specification
Result: The oil specification is incorrect.
Repair: Drain the engine oil system and refill the engine oil system. Refer to Operation and Maintenance Manual, "Engine Oil and Filter - Change".
Result: The oil specification is correct.
Proceed to Test Step 7.
7. Dirt in Fuel
A. Remove the fuel filters. Inspect the fuel filters for contamination.
Note: Contaminants in the fuel such as hydrogen sulfide and sulfur can lead to the formation of acids in the crankcase.
B. Obtain a fuel analysis.
Fuel and fuel filters
Result: The fuel has contamination.
Repair: Determine the cause of any contamination and make the necessary repairs.
Install new fuel filters. Refer to the Operation and Maintenance Manual.
Result: The fuel is