VALVE GP-RETARDER HYD CONTROL 1490978 - Caterpillar

Machine Preparation
Move the machine to a smooth horizontal location. Move away from working machines and personnel. Lower the work tools to the ground.
Allow only one operator on the machine. Keep all personnel away from the machine or in the view of the operator.
Engage the parking brake.
Illustration 1 g02703117
Place the steering frame lock in the LOCKED position.
Illustration 2 g02622290
Install Tooling (A) onto the hydraulic tank. Attach an air supply hose onto Tooling (A). Apply 276 to 414 kPa (40 to 60 psi) of air. This procedure will pull vacuum on the hydraulic system.Required Parts for 378-8421 Hydraulic Oil Lines Gp
Table 2
378-8421 Hydraulic Oil Lines Gp    
Item    Qty    Part Number    Description    
1     2     6W-2888     Fitting As    
2     2     6W-2890     Dust Cap As    
3     2     150-5430     Adapter As    
4     2     377-6220     Bracket    
5     2     378-0674     Hose As    
6     2     2P-1293     Locknut    
7     2     4J-0520     O-Ring Seal    
8     8     8T-4121     Hard Washer    
9     4     8T-4133     Nut    
10     4     8T-4185     Bolt    Installation of 378-8421 Hydraulic Oil Lines Gp
Illustration 3 g02920797
(4) 377-6220 Bracket (8) 8T-4121 Hard Washer (9) 8T-4133 Nut (10) 8T-4185 Bolt (B) Existing quick coupler group
Install bracket (4) to existing quick coupler group (B) using four bolts (10), four nuts (9), and eight washers (8) .
Illustration 4 g02920798
(1) 6W-2888 Fitting As (2) 6W-2890 Dust Cap As (3) 150-5430 Adapter As (6) 2P-1293 Locknut
Install fitting (1) to adapter (3). Then install to bracket (4) with locknut (6). Attach cap (2) onto fitting (1) .
Repeat Step 2 for the other side of the machine.
Illustration 5 g02920817
(5) 378-0674 Hose As (C) Existing bucket control group (D) Existing front lines group
Install one end of hose (5) to adapter (3). Install the other end of hose (4) to existing front lines group (D) .