Anthony Liftgates don't break often, but even the most rugged parts don't last forever. Damage or normal wear and tear can interfere with normal liftgate operation. We've prepared this section to help guide you step-by-step through the most common troubleshooting procedures for liftgate repair. Simply locate and click the description that most closely matches your issue, then follow the troubleshooting steps outlined on that page.

<< Return to Troubleshooting Guide

Platform lifts little or no load & platform drifts down when raised off ground, motor does run.  

Possible Cause #1 Air in hydraulic lines.
Action - Fill reservoir to within 1/2' of full with platform on ground with factory recommended Pennzoil Arctic hydraulic fluid, Dextron II if not available. (Power down models fill to 1/2' of full with platform raised).
(Diagnosis time -10 minutes / Repair time - 10 minutes).
Part Numbers - N/A
Possible Cause #2 Lowering Valve on liftgate power unit stuck in the open position.
Action - With platform on ground, remove lowering valve. Clean and inspect. If plunger will not move freely, replace.
(Diagnosis time - 1/2 hr. / Repair time - 15 minutes).
Part Numbers - ATU-121 (Monarch Lowering Valve)
ATU-479 (Fenner Lowering Valve)
Possible Cause #3 Defective cylinder piston seals.
Action - Remove breather tube from cylinder, activate raise control, see if oil is continuously pumped out. If yes, replace or repack cylinder. (If under warranty, replace cylinder. DO NOT repack or disassemble cylinder).
(Diagnosis time - 10 minutes / Repair time - 1/2 hr.).
Part Numbers - ATU-25100 (AST-1500, AST-2000, ASTL-1800, ATU-1800)
ATU-50100 (ASTL-2500, AST-2500, ATU-2500 Cylinder)
ATU-75100 (AST-3000, ATU-300, ATU-3500 Cylinder)
Possible Cause #4 Power unit relief valve on power unit set too low, or relief valve clogged with contaminates.
Action - Loosen lock nut and turn allen screw clockwise to increase pressure. Turn in all the way, then back out one full turn, retighten lock, test liftgate with load. If liftgate performs well, set pump pressure according to factory settings. Remove spring & ball, check for contaminates. Replace if pressure is not a problem.
(Diagnosis time - 15 minutes / Repair time 1/2 hr.).
Part Numbers - N/A
Warranty Information:
Base Warranty:

3 Years on mechanical structure.

2 Years on hydraulic & electrical components.

Warranties are void if genuine Anthony parts are not used.