CYLINDER BLOCK GP 1068230 - Caterpillar

Hydraulic System
Systematic checking of the system consists of three steps: 1. Visual Inspection; 2. Operational Check; 3. Pressure Check.Tests and adjustments of the hydraulic system can be made with 5S5123 Hydraulic Testing Group and suitable fittings. In all instances, visual checks and measurements should be made first. Then proceed to operational checks and finally to instrumentation checks.Visual Checks
A visual inspection of the system with the engine stopped should be the first step when troubleshooting a problem. With the bail lowered and the oil reasonably cool, perform the following inspections:1. Check the transmission lubricating oil level.2. Inspect all visible hydraulic oil hoses for breaks and check all connections for possible oil leaks.3. Inspect the hydraulic cylinder for oil leaking by the oil seal in the rod end of the cylinder.Operational Checks
PROBLEM: Noisy pump, erratic cylinder movement and/or excessive oil foaming. PROBABLE CAUSE:1 Air leak on inlet side of pump.2 Worn pump.3 Incorrect oil viscosity.4 Low pressure relief valve settings. PROBLEM: Overheating. PROBABLE CAUSE:1 Incorrect oil viscosity.2 Worn pump.3 Line restriction.4 Incorrect pressure relief valve setting. PROBLEM: Pump not delivering sufficient oil. PROBABLE CAUSE:1 Low oil level.2 Oil viscosity too high.3 Incorrectly assembled pump.4 Slow engine speed. PROBLEM: Low oil pressure. PROBABLE CAUSE:1 Pressure relief valves. a. Low pressure relief valve setting.b. Groove worn on contact surface of pilot valve.c. Foreign matter preventing pilot valve from seating.d. Dump valve stuck open.e. Orifice in dump valve clogged.2 Faulty control valve.3 Incorrectly assembled pump. PROBLEM: Cylinder rod does not extend (to lower bail). PROBABLE CAUSE:1 No signal oil pressure.2 Binding spool in control valve.3 Pressure relief valve open.4 Incorrectly assembled pump. PROBLEM: Cylinder rod does not retract (to raise bail). PROBABLE CAUSE:1 Binding spool in control valve.2 Control valve spool spring broken.3 Pressure relief valve open.4 Incorrectly assembled pump.Test Procedures
Bail Lift and Lower Circuit Speeds
The oil must be at normal operating temperature and be of the recommended viscosity to obtain accurate test results. The timed tests are made with the engine operating at high idle RPM.Bail lower and raise test times similar to the times listed indicate that the circuits are operating normally. However, the relief valves should be tested to be certain they are set at the recommended relief pressures. Relief Valve-Lower Circuit
Install a 5S4965 Pressure Plate Assembly, 5S4648 Hose Assembly and 7S8713 Pressure Gauge (0-1000 PSI) in the hydraulic line connection (1) at the head end of the cylinder. With the engine operating at high idle RPM move the bail position selector lever to DOWN position. When the bail pushes down against the stops the pressure should read 300 25 PSI (21,1 1,7 kg/cm2).When it is necessary to adjust the bail lower circuit relief valve (8), remove retainer (5) and either remove or add shims (6). The thickness of one 3H2549 Shim is .010 in. (0,25 mm). One shim will change the relief pressure setting approximately 40 PSI (2,8 kg/cm2).
TESTING BAIL DOWN RELIEF VALVE PRESSURE
1-Cylinder head end hydraulic line connection.
CONTROL VALVE
2-Shims. 3-Retainer. 4-Bail lift circuit relief valve. 5-Retainer. 6-Shims. 7-Retainer.