1. Remove shocks from car, refit any nuts and bolts to retain any bushings, clean first if necessary.
2. Remove spring retainer and spring, clean if necessary.
3. Using a dry paintbrush and paper tissue/rag, clean the shock.
4. Unscrew shock cap and clean, tip the oil into a waste oil container. Tech Tip: Notice that the shock cap has a cut bladder inside, I recommend this as the uncut bladder can burst which is a failure and will lead to some strange handling characteristics on the track. Cutting the bladder will ensure consistency and reliability.
5. Unscrew shock rod end and clean. Replace shock rod end if threads unwind too easily, this should be tight. Pliers may be used for holding the shaft but ensure a tight fit to ensure the shaft isn't damaged. Tech Tip:For easy removal of shock rod ends and shock maintenance, we recommend a Shock Shaft Vice.
6. Push shaft and piston out of shock body, wipe clean with paper tissue.
7. Open the o-ring cartridge/lower cap, and remove o-rings & guides. Clean all parts from cartridge, replace any damaged parts or any o-rings that look worn, swollen or dirty.
8. Check over the shock shaft for bends or damage. A shock shaft should be straight to avoid damage to the seals and prevent dirt entering the shock, leading to further damage. Replace the shaft if necessary. Clean the shock shaft with paper tissue to absorb any old oil. Motor/Cleaning spray can be used on the shaft to remove oil and clean, ensure that pistons and o-rings do not get sprayed.
9. Lubricate the o-rings and guides with a light shock oil or Green Slime, refit the parts into the cartridge/lower cap taking care not to damage the parts. Tech Tip: Using a 2mm hex wrench, slide the cartridge over the shaft, pour in a small amount of light shock oil and fit the o-rings & guides. The shock body can also be placed over the shaft and you can screw the lower cap/cartridge onto the body with ease.
10. Lubricate the shock shaft using shock oil as you did with the o-rings and insert the shaft back into the shock body taking care not to damage the o-rings or guides as you insert it.
11. Refit any external shock shims if necessary and wind on the shock rod end. It is recommended to tighten the rod end fully but it can be left slightly loose to achieve more droop from the shock. Ensure that both shocks (front or rear) are the same length with the rod tightened on.
12. With the shock shaft fully extended, fill the shock with your desired weight of oil to just below the top. Slowly pump the shock shaft up and down to remove any air bubbles, tap the shock and let it sit for a couple of minutes to let any air bubbles rise to the surface. Once the air has escaped, top up the shock with oil to the top.
13. Refit the shock cap and point the bleed hole on the cap upwards. Tighten the cap around half way on by turning the shock body into the cap, ensuring that the bleed hole points upwards. Air and excess oil will escape through the bleed hole.
Once the cap is screwed on half way you can set the rebound. For high rebound, insert the shaft all the way into the shock body and for low rebound, leave the shaft all the way out. Once you have this set, finish off screwing the shock cap on. Excess oil and air may escape through the bleed hole again, wipe this clean with tissue.
14. Repeat the steps for all the other shocks. Test that the shocks have the same rebound by simply pushing the shaft in, letting go and letting the shock shaft slide out. Match up the left and right shocks to ensure they have equal rebound. Repeat step 13 if the shocks do not match.
15. Re-fit the cleaned springs and retainers onto the shock
16. Re-fit the shocks to the car. Ensure that the top mount is not too tight as the shock needs to hinge and move freely on the standoff. Fit the shock rod end to the wishbone. Check the cars ride height and adjust the shock if required.
Written by Chris Long for JE Spares.