SHEET AS 6C1808 - Caterpillar

Boom Cylinder Drift
Refer to the following Testing and Adjusting for information on testing the boom cylinder drift. 1YS1-UP - Testing and Adjusting, SENR16362JR1-UP - Testing and Adjusting, SENR89616DR1-UP - Testing and Adjusting, SENR8971-01Manual Boom Lower Operation
Start the engine.
Fully extend the bucket cylinder (close bucket).
Fully retract the bucket cylinder (open bucket).
Raise the boom until the upper surface of the boom at the stick end becomes parallel to the ground. Stop the engine.
Illustration 1 g00295525
Bleeder Valve (1) Locknut. (2) Piston.
Loosen locknut (1) .
Slowly loosen piston (2) .
The boom should lower slowly and no oil leakage should be found.Note: A small amount of oil at screw (2) is not an indication of a problem.Relief Valves For Boom Cylinder Head End
Preparation
Illustration 2 g00296001
Pump Compartment (PIN: 1YS1-UP) (3) Main pump pressure tap. (4) Tap for power shift pressure.
Illustration 3 g00296002
Pump Compartment (PIN: 2JR1-UP) (3) Main pump pressure tap. (4) Tap for power shift pressure.
Illustration 4 g00296003
Pump Compartment (PIN: 6DR1-UP) (3) Main pump pressure tap. (4) Tap for power shift pressure.
Place the machine on level ground and stop the engine.
Release the pressure in the hydraulic system. Refer to Testing And Adjusting, "Hydraulic System Pressure - Release" for information on releasing the hydraulic pressure.
Connect a 60000 kPa (8700 psi) pressure gauge to main pump pressure tap (3) .
Connect a 4000 kPa (580 psi) pressure gauge to tap (4) .
Start the engine and raise the hydraulic oil temperature to 55° 5°C (131° 9°F).
Place the power mode selector switch in the POWER MODE position.
Place the engine speed dial at position 10 and maintain the maximum engine speed with no load on the engine. After the engine has been running for 3 seconds, read the engine speed.
Table 1
Engine Speed With No Load    
(PIN: 1YS1-UP)     2050 50 rpm    
(PIN: 2JR1-UP)     2010 50 rpm    
(PIN: 6DR1-UP)     1860 50 rpm    
Temporarily set the main relief valve pressure. Refer to Hydraulic System Testing And Adjusting for information on temporarily setting the main relief valve pressure.
Start the "Service Mode" and keep the power shift pressure constant. Note: Normal operations of the engine and pumps is necessary for the pressure adjustment. If the pressure adjustments are not correct, check the characteristic curve for the engine and the pump. If the pump flow is lower than the specification, verify that there is no air in the hydraulic system. Refer to Testing And Adjusting, "Piston Pump (Main) - Purge"for information on releasing air from the main pump.
Table 2
Power Shift Pressures    
(PIN: 1YS1-UP)    
2260 kPa (328 psi)    
(PIN: 2JR1-UP)    
2350 kPa (340 psi)    
(PIN: 6DR1-UP)    
2940 kPa (426 psi)    Test
Illustration 5 g00295989
Boom Lowering Control Valve (5) Locknut. (6) Adjuster.
Loosen locknut (5) on the left boom lowering control valve. Turn adjuster (6) clockwise by one quarter turn. Tighten locknut (5) .
Fully extend the boom cylinders. Hold the implement control lever in the Boom Raise position.
Read the pressure at pressure tap (3) .
Loosen locknut (5) on the left boom lowering control valve. Turn adjuster