HOSE AS 3078794 - Caterpillar

Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the machine. 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 in Caterpillar machines.Dispose of all fluids according to local regulations and mandates.
Table 1
Tools Needed    
8T-5320 Hydraulic Testing Group     1    
4C-4890 Hydraulic Test Group     1    
Illustration 1 g00346868
Location for pressure tap (M)
Illustration 2 g00343774
Location for pressure tap (N) This test will show if the parking brake release pump section is working properly. This test will also show if the relief valve for the parking brake release system is set correctly.
Remove the plug at location (M) or (N) . Install a nipple at the location of the removed plug.
With a coupler and a hose, install a 8T-0856 Pressure Gauge (0 to 6000 kPa (0 to 870 psi)) to nipple (M) or (N) .
While the parking brakes are activated, start the engine. Operate the engine at high idle rpm. The transmission should be in NEUTRAL. The pressure on the gauge must be at the relief valve setting.
Table 2
Model     Serial Range     Relief Valve Setting    
784B
785B
789B     5RK1-13
6HK1-331
7EK1-273    
4100 200 kPa (595 29 psi)    
784B
785B
789B     5RK14-UP
6HK332-UP
7EK274-UP    
4690 200 kPa (680 29 psi)    
Illustration 3 g00281783
Parking and secondary brake valve (1) Cap (2) Nut (3) Relief valve for parking brake release system
If the setting of relief valve (3) for the parking brake release system is too low, perform the following procedure:
Remove cap (1) . Loosen nut (2) .
Turn the threaded rod clockwise in order to increase pressure. One turn increases the setting approximately 690 kPa (100 psi) .
If the setting of relief valve (3) for the parking brake release system is too high, perform the following procedure:
Remove cap (1) . Loosen nut (2) .
Turn the threaded rod counterclockwise in order to decrease pressure. One turn decreases the setting approximately 690 kPa (100 psi) .
Tighten nut (2) . Replace cap (1) .
When you complete the test, stop the engine. Remove the test equipment.