CORE ASSEM. 8N5979 - Caterpillar

Swing Motor Relief Valve
(1) Cap.(Hyd #18) Swing Motor Performance Problem
Same tools as used for (Hyd #4)Spanner 22 mm (0.87 in.)Plug PF 3/8Measuring container1. Measurement Procedure a. Disconnect the drain hose of the swing motor from the block.b. Put the end of the drain hose into the container for measuring the case drain.c. Operate the swing lever, keeping the swing frame locked with swing lock pin.d. Measure the quantity of case drain for a minute. 2. Specification a. Swing motor relief pressure should be referred to (Hyd #16).b. Maximum case drain New machine ... 7 liter/min(1.8 U.S. gpm)After overhaul ... 10 liter/min(2.6 U.S. gpm)Service limit ... 15 liter/min(4.0 U.S. gpm)(Hyd #19) Swing Motor Check Valve
Any sticking of sliding surface, or damage of seat in the check valve allows the oil to vent to the return line.
Swing Motor
(1) Plug. (2) Spring. (3) Check valve. (4) Relief valve.* Removal and installation of check valve (3).Hexagon wrench 14 mm (0.55 in.) for plug (1).(Hyd #20) Check Of Travel Motor Crossover Relief Pressure
6V4161 Pressure Gauge Kit.8T0470 Thermometer Group.Standard New machine ... 33300 980 kPa (4800 140 psi)Machine after overhaul ... 33300 980 kPa (4800 140 psi)Service limit ... 33300 +980 -2950 kPa (4800 +140 -425 psi)Measuring procedureRefer to the section "Hydraulic System Testing And Adjusting".(Hyd #21) Travel Motor Crossover Relief Valve
6V4161 Pressure Gauge Kit.8T0470 Thermometer Group. Spanner 24 mm (0.94 in.) for lock nut (4).Hexagon wrench 10 mm (0.4 in.) for set screw (5).Pressure adjusting procedure * Refer to the item of travel motor crossover relief pressure adjustment in the section "Hydraulic System Testing And Adjusting".Travel crossover relief valve trouble Adjustment does not raise the pressure. Spring (3) is weak or broken.Sliding surface of poppet (2) sticks or its seat is damaged.
Travel Brake Valve
(1) Counterbalance spool. (2) Poppet. (3) Spring. (4) Lock nut. (5) Set screw.(Hyd #22) Travel Motor Counterbalance Valve Trouble
Traveling is impossible even though the crossover relief pressure is over the normal range.Spool (1) of the counterbalance valve sticks.(Hyd #23) Travel Motor Performance Deteriorated
6V4161 Pressure Gauge Kit.8T0470 Thermometer Group. Spanner 27 mm (1.06 in.)Leading hose for case drainDrain hose plug (931320)O-ring (951586)Measuring containerTrack stopper
Leading Hose For Case Drain 1. Measuring Procedure a. Disconnect drain pipe from the drain port (1) of the travel motor.b. Connect the leading hose.c. Put the end of leading hose into the measuring container.d. The disconnected drain hose must be plugged. Use O-ring.e. Fix the track with stopper. Operate the traveling lever.f. Measure the quantity of case drain for one minute.2. Specification a. Pressure New machine ... 33300 980 kPa (4800 140 psi)After overhaul ... 33300 +980 -1960 kPa (4800 +140 -285 psi)Service limit ... 33300 +980 -2950 kPa (4800 +140 -425 psi)b. Case drain New machine ... 15 liter/min.(4.0 U.S. gpm)After overhaul ... 15 liter/min.(4.0 U.S. gpm)Service limit ... 20 liter/min.(5.3 U.S. gpm)
Travel Motor
(1) Drain port.(Hyd #24) Rotary Joint Trouble
Damaged seals (2) at both ends of the rotary joint allows oil to vent to the drain. This causes a loss