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IMPORTANT: Always check leakage of lift cylinder seals before you test lift circuit
loader valve spool leakage.
18.3. LEAKAGE TEST FOR LIFT CIRCUIT LOADER VALVE SPOOL
NOTE: Clean all parts thoroughly before disassembling any fittings. Cycle or operate the hydraulic
system till the control valve is warm to the touch.
18.3.1. Install a pressure gauge in the lift circuit base end.
18.3.2. Cycle the lift cylinders to full extend and then full retract a minimum of 5 times to expel any air in the
system. The cylinders should be cycled with the engine near maximum rpm. The bucket should not be loaded
during cycling.
18.3.3. Place a load in the bucket and raise to some height. The load in the bucket and the lift height should be
such that it induces a target pressure of 1000 psi in the lift cylinder base end circuit.
18.3.4. Disconnect rod end lift cylinder circuit from loader valve by disconnecting quick coupler. If quick coupler
does not exist install one in line before proceeding with this test.
18.3.5. Use a permanent marker and mark a line on the cylinder rod 3 inches away from the tube end of the
cylinder. (See photo on following page)
18.3.6. After a 10 minute period of time measure the distance between the line and the end of the cylinder and
subtract the distance from 3 inches to determine how much the cylinder has retracted.
18.3.7. Refer to Leak down Rate chart in these instructions for the acceptable leak down rate for your specific
cylinder sizes.
Step A: Mark cylinder rod with a permanent marker
3” from cylinder end.
Step B: Then measure the distance between end of
cylinder and mark after a 10 minute period of time.
Rod End of Lift Cylinder
Initial Mark on Lift Cylinder Rod
3” from end of cylinder
18.4. LEAKAGE TEST FOR TILT OR BUCKET CYLINDER, SEALS
NOTE: Clean all parts thoroughly before disassembling any fittings. Cycle or operate the hydraulic system till the
control valve is warm to the touch.
18.4.1. Install a pressure gauge in the tilt circuit rod end.
18.4.2. Cycle the tilt cylinders to full extend and then full retract a minimum of 5 times to expel any air in the
system. The cylinders should be cycled with the engine near maximum rpm. The bucket should not be loaded
during cycling. Use regen function of valve (If equipped) when expelling air from the tilt circuit.
18.4.3. Lower the loader to the ground, relieve hydraulic pressure and disconnect rod end tilt cylinder circuit from
loader valve by disconnecting quick coupler. If quick coupler does not exist install one in line before proceeding
with this test.
35 Series 4WD, Model - 3535 & 4035 Loader June’08
