Oil at the rod end often leads directly to a seal-kit order. Before fitting new seals, inspect the rod bushing and mating surfaces. A worn guide, scored rod or damaged groove can quickly ruin replacement seals and leave the underlying fault unresolved.
Inspect before disassembly and again after cleaning
First make the machine safe and remove pressure and supported loads according to its service procedure. Record the cylinder serial number, bore, stroke and visible damage. Parker service bulletins call for checking rod burrs before removing a bushing, cleaning seal grooves and inspecting the bushing bore for wear. Another bulletin notes that rod scratches, dents and raised metal can damage seals as the rod moves. These are product-specific instructions; use the actual cylinder manual for dismantling and limits.
Engineering checks
- Check rod straightness and visible surface damage along the full stroke.
- Inspect bushing bore, bearing surface and out-of-round condition.
- Clean grooves and inspect edges that could cut a new seal.
- Check contamination and evidence of one-sided wear.
- Confirm the correct seal kit and assembly orientation from the serial number.
Common mistake to avoid
Forcing a bushing over a burred rod can cut its seals during removal or assembly. Polishing without checking the resulting dimensions can also hide rather than solve a damaged surface.
Data to send with an inquiry
- Nameplate or serial number and approved drawing.
- Leak location, operating pressure and fluid.
- Rod and bushing measurements with photographs.
- Maintenance history and failed seal components.
A repair plan should state which surfaces can be reused, which parts require replacement and how the assembled cylinder will be tested. For related selection guidance, see our seal failure diagnosis guide.
Technical references: Parker Series HD maintenance bulletin; Parker cylinder bushing service bulletin. Cover: original conceptual schematic, not a product photograph.