PLATE-END 5553401 - Caterpillar

Introduction
To determine if there is basis for a low swing force complaint enlist the help of someone experienced in the operation of the machine. Some components in the swing circuit can be tested to determine whether or not a problem exists. This test will determine whether there is a cause for low swing force. 1. Perform Swing Circuit Relief Valve Test And Adjust. For further information refer to the section, "Swing Circuit Relief Valve Test And Adjust". Results:* OK - Proceed to Step 2.* REPAIRED, OK - STOP.2. Perform Control Valve Shift pressure Test. For further information refer to the section, "Control Valve Shift Pressure Test". Results:* OK - Proceed to Step 3.* REPAIRED, OK - STOP.3. Check swing motor for leaking check (makeup) valves.a. Release the pressure in the hydraulic system. Refer to "Release Of Pressure In The Hydraulic System", Form SENR6187.
Pump Compartment
(1) Tap (rear pump pressure).b. Install 60 000 kPa (8700 psi) gauge at rear pump pressure tap (1).
Main Control Valve
(2) Elbow. (3) Line (swing parking brake signal).c. Prevent the swing parking brake from releasing by disconnecting pilot signal line (3) from swing brake control housing elbow (2). Cap elbow (2) and leave line (3) open.d. Move the swing pilot control lever to the swing LEFT and RIGHT and check swing crossover relief pressures [should be 23 000 kPa (3350 psi)].e. If either pressure is too low, trade positions with the left and right swing crossover relief valves.f. If the pressure remains low in the same swing direction, block the check valves closed in the swing motor and recheck swing pressure.g. If swing pressure is now correct, inspect check valves for sticking open or for damage to the valve or its seat. Expected Result:Swing crossover relief valve pressure is 23 000 kPa (3350 psi) in both directions in all tests. Results:* OK - Proceed to Step 4.* NOT OK - Check valve(s) is leaking. Replace swing motor check valves. If the check valve seats are damaged and cannot be repaired, replace the head of the swing motor. STOP.4. Check swing parking brake release pressure.a. Release the pressure in the hydraulic system. Refer to "Release Of The Pressure In The Hydraulic System", Form SENR6187.
Swing Motor
(4) Port (swing parking brake pressure).b. Install a 4000 kPa (580 psi) gauge at pilot system pressure port (4) in the swing parking brake valve.c. Move the swing pilot control lever to the swing LEFT or RIGHT position and check the pressure at the swing parking brake. Expected Result:The pressure to the swing parking brake should be approximately 3450 kPa (500 psi). Results:* OK - Proceed to Step 5.* NOT OK - Swing brake valve is faulty. Replace the swing parking brake valve. Repair binding brake piston. If piston cannot be made to move freely in its bore, the piston and/or the motor housing should be replaced. Reseal brake piston if leaking seals are preventing the brake from releasing. STOP.5. Perform Swing Bearing Clearance Test. For further information refer to the section, "Swing