Cylinder seal kits

Ideally the machine make, equipment model and the cylinder part number or kit code stamped on the body. Failing that, give the bore and rod diameters and photos of the removed seals, plus the groove sizes on the piston and gland.

Usually a piston seal, piston guide rings, rod seal, wiper, rod bearing and the static O-rings with back-up rings for the gland. Excavator or press cylinders may add a cushion seal. Check that the parts in the kit match those removed before fitting.

New seals cannot compensate for a scored rod, peeling chrome or a scratched barrel. Inspect the rod and bore surfaces before assembly, and clean the grooves and hydraulic oil thoroughly; leftover metal swarf will cut new seals within a few cycles.

For seals with a PTFE ring, warm them in oil at about 80 °C to soften, expand them over the piston with a tapered sleeve, then use a sizing ring to bring them back to size before sliding into the barrel. Never lever them with a screwdriver or sharp tool.

Yes, if the groove dimensions match, even when the kit codes differ. Measure the rod, bore, groove root diameter and groove length at each position and compare them with the kit's dimension list. The replacement seal profile may differ from the original but must have the same function and sealing direction.

You need a spanner for the cylinder head, plastic or brass seal picks, a tapered sleeve for fitting the piston seal and a sizing ring. For rod seals, a tool that folds the seal into a kidney shape helps insert it into the internal groove. Sharp metal tools such as screwdrivers scratch grooves easily and should be avoided.

Bleed air by stroking the cylinder fully several times at low pressure with no load. Then raise pressure and load gradually, checking for leaks at the wiper, head and fittings. Recheck drift under held load after a few hours of operation, once the seals have settled.

If the seals failed because of dirty, water-contaminated or overheated oil, change or filter the oil and replace the filter elements at the same time. New seals in a system full of abrasive particles will wear out again quickly. At minimum, take an oil sample and check cleanliness before deciding.