LATCH AS 1957691 - Caterpillar

Adjustment Procedure for 325B
Line Relief Valve
Hydraulic oil pressure can remain in the hydraulic systems after the engine and pump have been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic systems. To prevent possible injury, refer to the section, Testing and Adjusting, "Hydraulic System Pressure - Release" before any fitting, hose or component is loosened, tightened, removed or adjusted.When possible, the bucket or attachment must always be lowered to the ground before service is started. When it is necessary for the boom to be in the raised position while tests or adjustments are done, be sure that the boom, stick and bucket or attachment have correct support.The swing lock (if equipped) must be engaged before service is started.Always move the machine to a location away from the travel of other machines. Be sure that other personnel are not near the machine when the engine is running and tests or adjustments are being made.
Place the machine on a level surface.
Start the engine and warm the hydraulic oil to a temperature of 55° 5°C (131° 9°F).
Adjust the line relief valves for the bucket cylinder. Set the line relief valves for the head end and the piston end of the bucket cylinder at 19100 980 kPa (2750 140 psi). Refer to Testing and Adjusting, "Line Relief Valve - Test and Adjust" for the adjustment procedure.
Adjust the line relief valve for the head end of the stick cylinder. Set the line relief valve at 20100 980 kPa (2900 140 psi). Refer to Testing and Adjusting, "Line Relief Valve - Test and Adjust" for the adjustment procedure.
Adjust the line relief valve for the piston end of the boom cylinder. Set the line relief valve at 20000 965 kPa (2900 140 psi). Refer to Testing and Adjusting, "Line Relief Valve - Test and Adjust" for the adjustment procedure.Boom Down
Activate the boom priority mode.
Illustration 4 g00623328
(A) The stick cylinder is retracted. The boom cylinder is completely extended. (B) The boom is 2000 mm (78.75 inch) above ground level.
Place the machine in "position A", as shown. Refer to Illustration 4. The stick cylinder should be completely retracted. The boom cylinder should be completely extended.
Fully activate the boom down control. Measure the boom down travel time from "position A" to "position B". Refer to Illustration 4. The elapsed time for the boom down travel should be 4 .4 seconds. If the boom down travel time is not within specifications, proceed to step 4. Refer to Illustration 4.
Illustration 5 g00623699
Speed Control Valve (1) Locknut (2) Adjustment screw (3) Adjustment screw (4) Locknut
The speed control valve regulates the speed of the boom down and stick in functions. The speed control valve regulates pilot oil pressure to the main control valve. To adjust the boom down speed, determine the adjustment screw that is connected to the boom circuit in the main control valve. Extend the stick completely. Retract the boom cylinders until the bucket or