Pallet Jack Won’t Stay Up? Why It Slowly Lowers and What to Check
If a pallet jack raises and then slowly lowers, the system is losing hydraulic pressure. Check the release linkage, leakage, seals and valves in this order.
Okay, but then what if it lifts and slowly sinks? That is actually useful diagnostically: the pump can generate pressure, but the system cannot retain it.
Why this is different from “won’t lift”
If the jack reaches height normally and then sinks, the lift circuit has already proved it can move the ram. The question becomes where pressure is escaping.
First checks
- Make sure the lowering control is returning completely to neutral.
- Inspect the handle chain/tappet/linkage for a condition that leaves the release valve slightly actuated.
- Look for external oil leakage around the ram and pump.
- Compare drift unloaded versus under a known, safe load below rated capacity.
Internal leakage
If the release mechanism is definitely closed and there is no obvious external leak, internal leakage becomes more plausible. Worn seals or a valve/check component that cannot seal can allow pressure to bleed off without leaving a puddle.
At that point, the exact repair depends on the hydraulic unit design. An identifiable model with a parts diagram and seal kit is far more attractive than an anonymous jack whose pump assembly cannot be sourced.
Repair or replace?
Price the problem against the whole jack. If the wheels are also destroyed, forks are bent and the hydraulic unit is unknown, fixing one pressure leak may just reveal the next expense. If the frame is straight, wheels are healthy and a manufacturer-supported seal kit exists, the same symptom can be a reasonable repair.
Sources & verification
Manufacturer/primary sources are preferred where available. Prices and product listings can change; specifications should be checked again before a real purchase or transport decision.