COVER-BACK 4416013 - Caterpillar

TECHNICAL INFORMATION BULLETIN OCTOBER 17, 2001
EXCAVATORS THIS TECHNICAL INFORMATION BULLETIN REPLACES THE SEPTEMBER 12, 2001 EXCAVATOR TIBU3430, COMPONENT CODE: 5070, THE ACTUATOR ROD IN THE MAIN HYDRAULIC PUMP MAY WEAR PREMATURELY. DESTROY THE SEPTEMBER 12, 2001 TIBU3430. IT WILL NOT APPEAR IN THE SEMI-ANNUAL INDEX.
375 (8XG, 8WJ, 6NK),
375 L (6RL, 9WL, 1JM),
5080 (6XK, 8SL) EXCAVATORS
Component Code(s) 5070SUBJECT: THE ACTUATOR ROD IN THE MAIN HYDRAULIC PUMP MAY WEAR
PREMATURELY
PROBLEM:
Some actuator rods assembled in the main hydraulic pump may have received improper heat treatment. The ends of the rods may be soft and will wear prematurely. The symptoms of premature rod wear may appear on machines with a service meter hour reading of 700 hours or less. A machine will exhibit some of the following symptoms if the actuator rods are worn:
Excessive pump noise or shudder at high idle when the implement controls are in a neutral position.
Implement jerkiness during the fine control operation.
Engine lugging when the implement controls are fully engaged.
The actuator rod length affects the pump output. An increased standby pressure may indicate that the rod is worn. The pump output standby pressure should range from 2620 kPa to 3100 kPa (380 psi to 450 psi) at high idle with the implement controls in a neutral position.
October 17, 2001
Component Code(s) 5070
SOLUTION:
Disassemble the pump and inspect the 6E-3871 Actuator Rod for abnormal wear. Use the following procedure for determining replacement of the actuator rod:
Install swashplate (B) in the cradle bearings in the pump housing.
Position the swashplate face parallel to the end face of the pump housing (F) and 90 degrees to the centerline of the pump shaft.
Install rod (1) and piston (2) as shown.
Hold the rod and piston at 90 degrees to the swashplate and measure the distance from the housing face to the lower edge of the piston cross-hole (E).
Select the rod to get the clearance dimension (D). The rods available for correct adjustment of the minimum displacement of the 6E-1026 Actuator Group are listed in the table.
Actuator Rod Length Table
Part Number Length
6E-3871 185.00 mm (7.283 in)
145-3321 184.70 mm (7.272 in)
145-3322 184.90 mm (7.280 in)
145-3323 184.60 mm (7.268 in)
145-3324 184.80 mm (7.276 in)
October 17, 2001
Component Code(s) 5070
Illustration 1. Typical Hydraulic Pump Actuator Group
(1) 6E-3871 Actuator Rod
(2) Piston
(A) Detail Of Rod And Piston
(B) Swashpate
(C) 90 Degrees
(D) 0.55 ! 0.05 mm (0.022 ! 0.002 in)
(E) Piston Cross-hole
(F) End Face Of The Pump Housing
COPYRIGHT 2001 CATERPILLAR
ALL RIGHTS RESERVED