Cylinder seal kit 40x70 991/20021 JCB, aftermarket, option 1

Cylinder seal kit 40x70 991/20021 is an aftermarket part for the JCB machines. According to the product card, the kit is for a cylinder with a 40 mm rod and 70 mm bore.

The kit is chosen by the rod and bore diameters of the cylinder (for example 50 x 80 mm) and by cylinder type. Even two cylinders with the same diameters can have different seal profiles and groove sizes, so the kit is chosen by the cylinder's part number or the kit's own number. The number and shape of the parts depend on the gland and piston design of the cylinder.

Specifications

Compatibility

According to the product card, 991/20021 is a hydraulic cylinder seal kit. Fit is confirmed by the cylinder or kit part number. The catalogue also has the aftermarket version of this part. Other parts are in Repair kits.

Fitting

Before the repair, disconnect the cylinder from the hydraulics, release the pressure and clean it outside, then dismantle it on a clean bench. Remove the old seals with plastic or brass tools so the grooves are not scratched. Wet the new seals with clean hydraulic oil and fit them the right way round; piston seals can be softened in warm oil if needed and sized with a calibrating sleeve. Pass the rod through the gland without damaging the seal and tighten the piston nut to the specified torque. After assembly, cycle the cylinder through full strokes a few times without load to purge air and check for leaks.