PLATE-RELAY 1G7878 - Caterpillar

Personal injury or death can result from sudden machine movement.Sudden movement of the machine can cause injury to persons on or near the machine.To prevent injury or death, make sure that the area around the machine is clear of personnel and obstructions before operating the machine.
Personal injury can result from hydraulic oil pressure and hot oil.Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system.Make sure all of the attachments have been lowered, and the oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.
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.
Note: The illustrations in the following procedure show the Water Delivery System installed on a 777F Off-Highway Truck.
Table 1
Required Tools
Tool Part Number Description Qty
A 8T-0855 Pressure Gauge
0 to 4000 kPa (0 to 580 psi) 2
6V-4144 Quick Connect Coupler 2
B 177-7860 Hose As 2
6V-4142 Fitting 2
6V-4143 Quick Connect Coupler 2
C 6V-9510 Plug 1
D 7J-9108 O-Ring Seal 1
E 6V-3831 O-Ring Seal 2
F 153-6233 Union As 1
Table 2
Optional Tools(1)
Tool Part Number Description Qty
G(2) 198-4234 Digital Indicator 1
H(2) 198-4236 Adapter Cable As 2
J 198-4237 Pressure Sensor Gp
0 to 3500 kPa (0 to 500 psi) 2
(1) The optional tools can be used to replace the analog pressure gauges in the required tool list.
(2) Tool (G), Tool (H), Tool (J) are part of the 198-4240 Digital Pressure Indicator Gp.
Drive the machine to a smooth, horizontal surface.
Place the transmission gear selector in the PARK position.
Operate the engine at low idle for a few minutes. Shut down the engine.
Place blocks in front of the rear wheels and behind the rear wheels.
Assemble Tool (A) and Tool (B). Connect Tool (A) to Tool (B).
Illustration 1 g02772977
Locate charge filter (1). Install Tool (B) on charge pressure tap (2).
Start the engine. Run the engine at high idle in order to warm the hydraulic oil.
Monitor the hydraulic oil temperature. Operate the machine until the oil temperature reaches 43 5.6 °C (110 10 °F).
Record the pressure at charge pressure tap (2). The pressure should be 1930 kPa (280 psi).
Operate the engine at low idle for a few minutes. Shut down the engine
If the pressure is within the specified range, go to Step 14. If the pressure is not within the specified range, go to Step 12.
Illustration 2 g02773698
Locate