The hydraulic cylinder in a pallet truck (hand pallet jack) operates under demanding conditions: repetitive lift-and-lower cycles, variable loads, and constant exposure to floor-level contaminants. Choosing the right seals — both in the gland (also referred to as the cylinder cap or rod seal housing) and on the piston — is critical to the longevity and leak-free operation of the hydraulic system.
When Should You Replace the Seals?
Seal wear typically presents itself through clear symptoms: visible hydraulic oil leakage along the rod, gradual loss of working pressure (the truck fails to hold height or lifts more slowly than usual), and in more advanced cases — sticking or uneven cylinder movement.
Components of a Seal Kit
A typical pallet truck hydraulic cylinder seal kit consists of three types of elements:
Rod Seal (U-ring)
Installed in the gland bore, it seals the rod during its reciprocating motion. Typically made from polyurethane (PU), which combines abrasion resistance with flexibility across a wide temperature range.
Wiper / Scraper Ring
Mounted on the outer face of the gland. Its job is to mechanically remove contaminants — dust, mud, abrasive particles — from the rod surface before they enter the sealing zone, protecting the rod seal from premature wear.
O-Ring
Used as a static seal between cylinder body components or in the piston groove. Typically made from NBR (nitrile rubber), which offers reliable resistance to mineral hydraulic oils.
Seal Kit Configurations for Common Rod Diameters
Kit for Ø18 mm
| Component type | Part no. / dimensions | Link |
|---|---|---|
| Rod seal PU | A154 PU 18×26×5 | lemming.shop |
| Wiper ring PU | K103 18×26×4.5/6 | lemming.shop |
Kit for Ø28 mm
| Component type | Part no. / dimensions | Link |
|---|---|---|
| Rod seal PU | A154 28×35.5×5 | lemming.shop |
| Wiper ring PU | A208 28×36×5/7 | lemming.shop |
| O-ring NBR | 28×4 NBR70 | lemming.shop |
Kit for Ø31.5 mm
| Component type | Part no. / dimensions | Link |
|---|---|---|
| Symmetric rod seal PU | A101 31.5×41.5×6.0 | lemming.shop |
| Wiper ring w/ secondary seal PU | A208 31.5×39.5×5/6.5 | lemming.shop |
Summary
The configurations listed above reflect typical solutions used in hydraulic cylinders of popular pallet truck brands. Before ordering, always verify the dimensions directly on the disassembled cylinder — manufacturing tolerances and design details can vary between models and manufacturers.