CONT GP 1096629 - Caterpillar

Introduction
Internal leakage of the swing motor (case drain leakage) can be an indication of the condition of the motor. Excessive case drain leakage could lead to swing control, speed, and force complaints. Check swing motor case drain leakage
Swing Gear
(1) Mark (upper structure). (2) Mark (lower structure). (3) Mark (lower structure).a. Place the machine on level ground and position the upper structure straight ahead so a bolt in the upper structure is aligned with a bolt in the lower as shown.b. Place mark (1) at the bolt in the upper structure.c. Place mark (2) on the lower structure so that it is midway between the second and third bolts. Place mark (3) on the lower structure so that it is midway between the third and fourth bolts of the lower structure.d. Release the pressure in the hydraulic system. Refer to "Release Of Pressure In The Hydraulic System", Form SENR6187.
Main Control Valve
(4) Elbow. (5) Line (swing parking brake signal).e. Disconnect pilot signal line (5) from swing brake control housing elbow (4) and cap line (5). Leave elbow (4) at the swing brake control housing open.
Swing Motor
(6) Line (swing motor case drain).f. Disconnect swing motor case drain line (6) from the motor and block the line.g. Connect the vinyl hose to the swing motor case drain port and place the other end in a suitable container.h. Increase the hydraulic oil temperature to the normal operating temperature.i. Move the swing pilot control lever to the full LEFT or RIGHT swing position.j. Measure the case drain leakage for 15 seconds while holding the swing pilot control lever in the full swing position (at swing system relief pressure).k. Release the pressure in the hydraulic system. Refer to "Release Of Pressure In The Hydraulic System", Form SENR6187.l. Reconnect swing parking brake pilot signal line (5) to the swing brake control housing elbow (4).m. Move the upper structure so that mark (1) is aligned with mark (2) on the lower structure.n. Repeat Steps d, e, i, and j.o. Repeat Steps k, and l.p. Move the upper structure so that mark (1) is aligned with mark (3) on the lower structure.q. Repeat Steps d, e, i, and j.r. Calculate the average the three case drain measurements. (Add the three case drain measurements and then divide them by 3. Multiply the result by 4 to determine the amount of case drain flow per minute.) Expected Result:The average of the case drain measurements should be 15 liter/min (4.0 U.S.gpm) for a new motor, 17 liter/min (4.5 U.S.gpm) for a rebuilt motor and a service limit of 20 liter/min (5.3 U.S.gpm). Results:* OK - STOP.* NOT OK - Repair the swing motor. STOP.