Kyosho W5303-04GM Big Bore Seal Cartridge Set

Kyosho W5303-04GM is a genuine seal cartridge set for Kyosho's big bore shocks. The cartridge is the assembly that threads into the bottom of the shock body and holds the seals and bushings that the shaft passes through, so it does the two jobs that decide how a damper performs: it seals the oil chamber and it keeps the shaft running true. A worn or damaged cartridge causes leaks and stiction that no amount of oil or piston tuning will correct.

Kyosho supplies this as a complete two-set pack, which is the sensible way to service dampers in pairs and keep both sides of an axle matched. It is the designated spare for Kyosho's W5303 and W5304 big bore shock sets, fitting the Ultima RT5, RB5, and SC along with the Lazer ZX-5 series. Installation is a direct swap during a normal shock rebuild. Fit the new cartridge with fresh seals and oil and the shock comes back to smooth, leak-free operation.