Instructions for Rebuilding a Dirt Bike’s Rear Shocks

Dirt bike is exposed to a rugged environment. From handling nature’s elements and rider abuse to absorbing large jumps. Not too many mechanical devices need to be as durable as a dirt bike. Many parts on a dirt bike require regular maintenance to ensure an enjoyable and safe ride. One of those parts is the bike’s shocks. These are often neglected because few people understand how they work. For the most part, a shock rebuild can be done in a few hours with some common tools.


1) Put the shock in a vise and compress the spring with your hands to release the pressure on the spring retainer. Remove the retainer and spring.

2) Release the pressure inside the shock with the valve on its side. You may need an inflation/needle tool depending on your style of shock. Some oil may splatter out of the valve, so point away from your body.

3) Unscrew the cap with the wrench and remove the guts of the shock by pulling upward.

4) Place the shock’s shaft in the vise and loosen the nut that secures the damping piston. Remove the piston assembly and make sure to remember the order of the parts.

5) Clamp the shock’s body to the vise and pry out the seal. Be careful not to damage the body when removing it.

6) Remove the O-ring seals from the internal components with a plastic or aluminum pick.

7) Clean all of the parts with brake cleaner and reinstall new seals and O-rings.

8) Reassemble the piston in the reverse order you disassembled it in.

9) Secure the shock’s body in the vise and insert the piston assembly inside. Do not push it all the way in so that you can fill the body with new oil.

10) Fill the shock body with oil up to 1 inch from the top.

11) Insert the assembled shaft into the body in a circular motion. Fasten the piston assembly to the body by screwing the seal head down and tightening.

12) Fill the shock with nitrogen using the Schraeder valve and pressurize it to 250 p.s.i. If you don’t want to invest in a nitrogen tank, most shops will perform this task for a nominal fee.

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