VALVE GP-RELIEF 4564633 - Caterpillar

Personal injury or death can result if two persons are not used in the following procedure.
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 Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products.Dispose of all fluids according to local regulations and mandates.
Use this procedure in order to determine if the service life of the brake discs has been exceeded.
Illustration 1 g00868472
Service Brake Disc Wear Indicator (1) Retaining ring. (2) Washer. (3) Piston. (4) Piston housing. (5) Dowel. (6) indicator pin. (B) Visible length of indicator pin.Each individual service brake uses an indicator pin (6) to determine if the service life of the friction discs has been exceeded. The indicator pin can be viewed through an inspection port. There is an inspection port at each service brake.
Move the machine to a hard, level surface. The surface must also be dry and free of debris. Engage the parking brake.
Start the engine. Run the engine until the brake accumulators reach the cut-out pressure. Stop the engine.
Apply the service brakes once in order to ensure proper positioning of the indicator pin (6). Hold the brake pedal in the applied position.
Illustration 2 g00839612
Inspection port Location on the Axle
Remove the inspection port plug. Look through the inspection port on the axle housing. If the indicator pin (6) is visible, then the friction discs for the service brakes do not need to be replaced. If the indicator pin is not visible, then the friction discs for the service brakes need to be replaced.Note: The maximum visible length of the indicator pin (B) is approximately 3.25 0.25 mm (.128 .01 inch).
Replace the inspection port plug.
Repeat steps 3 through 5 for each of the service brakes. Reference: For more information on the service brake disc wear indicator, refer to the Service Manual module System Operation, "Service Brake Disc Wear Indicator ".