| Possible Cause #1 |
Little or no hydraulic fluid in reservoir. |
| 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 stuck partially or fully open. |
| Action- |
|
With platform on ground, remove lowering valve and inspect. Clean if dirty. Replace if plunger not freely moveable.
|
| (Diagnosis
time - 1/2 hr. / Repair time - 15 minutes). |
|
| Part Numbers - |
|
ATU-121 (Monarch Lowering Valve)
|
|
ATU-479 (Fenner Lowering Valve)
|
|
| Possible Cause #3 |
Cylinder piston seal blown allowing fluid to leak past piston when trying to raise platform. |
| Action - |
|
Remove breather hose from end of cylinder. Activate power unit to raise position, if hydraulic fluid pumps out o f breather port, repack or replace cylinder. (If under warranty, replace cylinder - DO NOT repack or dismantle.
|
| (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) |
| ATU-25113-WR
(ATU-25100 Seal kit) |
| ATU-50123-WR
(ATU-50100 Seal kit) |
| ATU-75112
(ATU-75100 Seal kit) |
|
| Possible Cause #4 |
Power unit relief valve on power unit set too low. |
| 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 nut, test liftgate with load. If liftgate performs well, set pump pressure according to factory settings.
|
| (Diagnosis
time allowed - 15 minutes / Repair time - 1/2 hr.). |
|
| Part Numbers - |
N/A |
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