Rebuilding a shock
Note: These rebuild instructions are specific to the Fox shock, but they will work for any rebuildable/serviceable shocks (some late model stock units, but mostly aftermarket models). Don't try this on your Showa EX250 damper.
1. Remove spring and clean shock thoroughly.
2. Back out rebound to minimum setting (3 turns out).
3. Loosen allen hex head set screw located on knurled cap on top of the body, where the shaft comes out.
4. Turn the knurled cap counter clock-wise with a pair of channel locks (or you can make a tool with dowel pins on a 1.5" center to center points). Underneath this cap is the main bearing and seal housing.
5. Depressurize the shock completely by removing the valve core from the valve stem. With your fingertips, press down on the bearing housing until wire circlip is exposed enough to be able to remove it with a scribe.
6. Remove shaft assembly by rocking back and forth and pulling out at the same time. NO parts will drop away from the shaft assembly; only oil.
7. Dump oil into a bucket.
8. Using a rubber mallet, tap the valve stem and cap into the reservoir, exposing the wire circlip ring.
9. Remove ring with a scribe. DO NOT scratch the reservoir inside.
10. Put valve stem cap back on valve stem. Using a pair of pliers, pull the cap out of the reservoir. Spray inside of reservoir with a lubricating spray. Reach into reservoir with pliers and grab reservoir floating piston and gently pull all the way out. (Fox also offers a reservoir piston tool).
11. Clean body and reservoir, which should still be attached to each other, with a clean towel and blow dry them completely with compressed air.
12. To remove the bearing housing from the shaft, you will first have to make some shaft clamps out of aluminum or wood. (Shaft Dia. is 5/8") After you have the shaft clamped in the vise, remove the 3/4" nut from the top of the shaft.
13. Remove the valving assembly. This includes the rebound valve stack, which is on the top of the piston, the compression stack, and the top out washer. Pull them off all at the same time and keep parts together in the same order.
14. Remove the bearing housing.
15. Remove the bearing housing cap. (knurled cap)
16. With a scribe, remove the wiper, the inner o-ring and outer o-ring from the bearing housing.
17. Remove scraper seal from bearing housing cap.
18. Clean both parts in solvent. Blow off with air.
19. Put new seals and o-rings back into parts. You should be able to do this with just your fingers.
20. Slide bearing housing cap back onto shaft.
21. Slide bearing housing onto shaft. DO NOT force it on; use a slight rocking motion to reinstall it.
22. Put the valving assembly back onto shaft in the same order as you took it off. This is very important.
23. Put the lock nut on the shaft loosely and spray the valve assembly with a contact cleaner or a spray brake cleaner. Gently blow off with compressed air.
24. Torque lock nut to 35 ft-lbs. Take shaft out of vise.
25. Put body in vise so that body opening is up.
26. Make sure there is no dust or dirt in body or reservoir. If dirty, clean again and blow dry.
27. (see FIG A:) Hold reservoir up next to body with opening up. Fill reservoir with oil all the way up to the top.
28. (see FIG B & C:) Push reservoir piston into reservoir body all the way to the bottom, forcing oil (and air bubbles) up through the hose and into the body. Slowly pull reservoir piston back out (about 1/2 way) and push back in. (This procedure will flush out any air trapped in the CD Housing). Push in and out slowly until there are no air bubbles coming up into the body (about 4-5 times). Finish with the piston in the bottomed-out position.
29. Install reservoir cap & wire ring. Pull reservoir cap back out against the wire ring & pressurize to 50 P.S.I.
30. Now, take the shaft assembly and pull the bearing and bearing cap back away from valving assembly. Insert valving assembly into oil in body and stroke until no air bubbles arise. Bring shaft back up toward the top of the body (but still immersed in oil, add oil if necessary). Now, while holding shaft steady, slide bearing down into oil in body. Make sure that the small hole drilled in the side of the bearing housing is not pointed at yourself, or anything you do not want to have oil on. It can squirt up to 6 ft. Push bearing into body until you reach the outer bearing housing O-ring.
31. At this point, you may need another person to help.
32. Depressurize shock while (at the same time) pushing the bearing housing in past the wire ring groove.
33. Reinstall wire ring into groove. Make sure it is seated properly.
34. Pressurize the reservoir to 300 P.S.I. to seat bearing housing up against the wire ring. (200 P.S.I. for cars and oil road shocks)
35. Clean any oil left on top of the bearing housing.
36. Screw on the bearing housing cap until snug. Use a pair of channel locks and a rag to snug up the cap.
37. Tighten allen screw on top of cap to lock cap in place.
38. Put valve cap back on. You are finished.
FOX RACING SHOX