SENSOR GP-PRESSURE 3431771 - 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, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat products.Dispose of all fluids according to local regulations and mandates.
Introduction
This information includes the following Check procedure:
Service Brake Wear IndicatorUse this procedure in order to determine if the service life of the brake discs has been exceeded.Test Preparation
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 cutout pressure. Stop the engine.Test Procedure
Illustration 1 g00868472
Service Brake 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 a port in the axle. There is a port with an inspection plug at each service brake.
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
Location of the inspection plug on the axle
Remove the inspection plug. Look through the port of the inspection plug on the axle housing. If the indicator pin (6) is visible, then the friction discs for the service brakes are still good. If the indicator pin is not visible, then the friction discs for the service brakes should 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 plug.
Repeat steps 1 through 3 for each of the service brakes.ReferenceFor more information on the service brake wear indicator, refer to the Service Manual module System Operation, "Service Brake Wear Indicator".