IMPELLER A. 6F0237 - Caterpillar

Valve Identification
Lowering Control Valves
Illustration 1 g03318947
Boom lowering control valve (7) Boom cylinder (8) Line relief valve (boom cylinder head end)
Illustration 2 g03318949
Stick lowering control valve (9) Line relief valve (stick cylinder rod end) (10) Stick cylinderRelief Valve Test
Table 1
Required Tools    
Item    Qty    Part No.    Description    
(A)     1     8T-0860     Gauge 0 to 40000 kPa    
(B)     1     3S-6224     Electric Hydraulic Pump    
(C)     2     8F-0024     Hose Assembly    
(D)     2     1P-2375     Coupler Assembly    
(E)     2     1P-2376     Coupler Assembly    
(F)     2     1P-2377     Plug    
(G)     1     7J-8611     Elbow    
(H)     2     3B-7722     Bushing    
(J)     2     030-8370     Adapter    
(K)     1     288-6823     Manifold    
Use the following Steps in order to test or check the appropriate line relief valve setting:
Lower all of the work tools to the ground.
Stop the engine.
Release the pressure in the hydraulic system. Refer toTesting and Adjusting, "Hydraulic System Pressure - Release"
Remove the line relief valve from the main control valve that will be tested.
Illustration 3 g03268076
(C) Hose assemblies (D) Couplers (E) Couplers (J) Adapters (K) Manifold (L) Line Relief valve
Secure manifold (K) in a suitable holding device.
Install two adapters (J) and two couplers (D) in manifold (K) .
Attach two couplers (E) to two hose assemblies (C) .
Install line relief valve (L) in manifold (K) .
Connect hose assemblies (K), two bushings (H), and elbow (G) to electric hydraulic pump (B) .
Connect gauge (A) to electric hydraulic pump (B) .
Turn electric hydraulic pump (B) to the ON position. Check for leaks at the connection.
The 3S-6224 Electric Hydraulic Pump only has a 7.6 L (2 US gal) reservoir. Pump damage may result if the pump is operated with an empty reservoir.
Slowly increase the pressure. Record the pressure at which line relief valve (L) opens. Compare this pressure to Table 2.
Stop the pump.
Table 2
Relief Valve (Line) - Test and Adjust    
Relief Valve    Pressure Setting    Actual Pressure    
Stick (Rod End)    
30400 300 kPa (4410 40 psi)        
Boom (Head End)    
Illustration 4 g03268116
Line Relief Valve (M) Cap (N) Adjustment screw (P) Locknut
If line relief valve (L) is within the specifications, then go to Step 17. If the line relief valve is not within the specifications, then an adjustment is required.
Remove cap (M). Loosen locknut (P) and turn adjustment screw (N) clockwise in order to increase pressure. Turn adjustment screw (N) counterclockwise in order to decrease pressure.
Check the oil level in electric hydraulic pump (B) and refill the oil if necessary. Repeat Steps 12, 13, 14 and 15.
Tighten locknut (P) .
Remove line relief valve (L) from manifold (E) .
Install a new O-ring on line relief valve (L) .
Install line relief valve (L) to a torque of 100 10 N m (74 7 lb ft).