VALVE AS 4828401 - Caterpillar

Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids.Refer to Special Publication, NENG2500, "Caterpillar Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Caterpillar products.Dispose of all fluids according to local regulations and mandates.
Before performing any procedures on the machine, read Service Manual Module, "Machine Preparation for Trouble Shooting" and understand the steps in Service Manual Module, "Machine Preparation for Trouble Shooting".If the oil becomes contaminated, premature component failure could result. Contaminated oil can also contribute to overheating. Use the following procedure to sample the oil in the hydraulic system.
Engage the parking brakes and start the engine.
Run the engine at HIGH idle.
Actuate all cylinders through a minimum of ten full cycles.
Actuate the service brakes in order to cycle the charging system for the brake accumulators.
Lower the work tools to the ground.
Stop the engine.
Move all control levers and brake pedals through all positions in order to release any pressure in the hydraulic system.
Start the engine.Note: Do not operate the hydraulic controls.
Run the engine at LOW idle.
Illustration 1 g01408326
Port Location (A) Sampling port.
Draw a 50 mL (1.7 fl oz) oil sample from sampling port (A). The level of contaminants must be lower than the values in the following table.
Table 1
Hydraulic Oil Contamination    
Particle Size (Microns)     Maximum Number of Particles    
10 to 20     48000    
21 to 50     2580    
51 to 100     150    
100 or more     20    
If the level of contamination is below the specification, then install a new oil filter on the machine. Proceed to step 12. If the level of contamination is not below the specification, perform the following procedure.
Drain the hydraulic oil from the tank.
Fill and flush the hydraulic system.
Fill the hydraulic tank. Refer to the Operation and Maintenance Manual for the proper capacity of the tank.
Install a new oil filter on the machine.
Repeat steps 1 through 11.
Stop the engine.