GAUGE GP-CLUSTER 3838496 - Caterpillar

Check For Leakage In The Master Cylinder
Illustration 3 g00511516
Rear Slack Adjuster
(3) Fitting
(4) Hose
Illustration 4 g00284783
Front Slack Adjuster
(3) Fitting
(4) Hose
In order to check for leakage of the master cylinder, disconnect hose (4) from the slack adjuster and install a plug in fitting (3). Use a 6V-9509 Face Seal Plug with the front brake system.Use a 6V-9511 Face Seal Plug for the rear brake system.
Install the FT1097 Displacement Gauge. Start the engine and allow the air system pressure to rise above 550 kPa (80 psi).
Activate the service brakes or the retarder. Push down the rod of the displacement gauge until the rod contacts the plate in the master cylinder. Measure the extension of the rod.
After approximately 10 minutes, push down on the rod again. Measure the distance. A decrease in the extension length of more than 3.2 mm (.125 inch) during the 10 minute check is an indication of leakage.
If no leakage is indicated, see "Brake Piston Seal Leakage Check".
If leakage is indicated, check all hose connections for leaks. Also, check the outside of the master cylinder for leaks. If no external leaks are found, check the master cylinder piston seals and the makeup valve for wear or for damage. Brake Piston Seal Leakage Check
Table 2
Tools Needed Qty
FT1097 Displacement Gauge 2
6V-9830 Cap Assembly 1
6V-9831 Cap Assembly 1 Remove the air pressure from the air system for the service brakes and for the retarder brake system before you remove the plug from the brake master cylinders.
Personal injury or death can result from sudden machine movement.Sudden movement of the machine or release of air pressure or oil pressure can cause injury to persons on or near the machine.To help prevent possible injury before testing and adjusting any air system or hydraulic system, perform the procedure in the Testing and Adjusting, "General Information" section.
Personal injury or death can result from machine movement.Place blocks in front of and behind the wheels to make sure the machine does not move while the parking brakes are disengaged.
Illustration 5 g00345696
(S/N: 2PZ1-105)
(S/N: 1HW1-Up)
(S/N: 5AZ1-399)
(S/N: APX1-450)
Location of Plugs
(1) Plug on the front brake master cylinder
(2) Plug on the rear brake master cylinders
Illustration 6 g01070270
(S/N: 2PZ106-Up)
(S/N: 5AZ400-Up)
(S/N: APX451-Up)
Location of Plugs
(1) Plug on the front brake master cylinder
(2) Plug on the rear brake master cylinders Note: Make sure that the air pressure is removed from the system before you continue with this procedure.
Remove plugs (1) and (2) from the brake master cylinders. Install an FT1097 Displacement Gauge.
Do not exceed the air pressure of 830 35 kPa (120 5 psi) or damage can occur to the air system components.
Use an external air supply to charge the air system.
Start the engine. Allow the air pressure to reach the cut out pressure. Keep the engine in operation during this procedure to ensure correct air pressure.
Move the parking brake control valve to the OFF position.
Activate the service brake or the retarder.
Push down the rod of the FT1097 Displacement Gauge until the rod contacts the plate in the master cylinders.
Measure the length of