This is a guide on how to replace the oil of Quantum Zero one-way shocks (dampers).
Two years-ago I purchased and installed Quantum Zero one-ways with 525/650 springs and 200/300 helpers (Quantum Racing Suspension | Racing Shock Absorbers
) from www.EliseParts.com
. While not distributed in the USA, Quantums have a strong track/race pedigree and are quite popular among U.K. Elige owners.
With nearly 40 total track days over two years and 8,000 total miles on these shocks, I decided to replace the shock oil. I did this as winter maintenance and on the recommended schedule, per Quantum.
1. Remove shocks from car.
2. Brush off loose dirt to reduce interference when unscrewing compression ring.
3. Mount in vise and measure the distance from the compression ring to the shock tower cap. This will help you re-set the compression to the correct level, when finished (pictured).
4. Unscrew compression ring to reveal circlip.
5. Remove circlip and spring-stack (collar, helper spring, spacer, spring) (pictured)
6. Wash everything (warm water, mild dish soap, plastic bristle brush) and dry.
7. Unscrew piston bushing cap using Facom 117.B (pictured).
8. NOTE: I had to slightly grind down the tool so it would clear the piston shaft (pictured).
9. Once cap is removed, pull out piston and set aside so any oil in it can drain out (pictured).
10. Empty old oil by simply tilting the shock tube into a catch can. Note condition of oil (pictured). My oil was still translucent brown (good), but had particles which were small bits of anodized coating which had worn off (bad), indicating an oil change was wise. All, as explained to me by Quantum. I emailed them the picture.
11. Refill shock tube with fork oil (I used Motul 5w fork oil) almost to the top. Yes, you will have ‘slop’ (spillage). You want that to reduce chance of air pocket.
12. Reinstall piston and jiggle to remove air. Best to watch this video:
13. This is important, make sure piston is almost fully extended, but still covered by oil in the tube. (pictured).
14. Begin screwing in the piston bushing. Ideally, the bushing will bump into the piston with about two turns before the bushing is fully seated.
15. Fully screw in the bushing, taking care that oil will overflow and need to be cleaned up. Wipe off excess, overflowed oil.
16. Test adjuster ring to make sure it ‘clicks’. Mine didn’t the first try because I failed to have the piston fully extended when tightening the bushing (step 13).
17. Clean shock tube from all remaining oil slop. I used compressed air and paper towels.
18. Re-install springs and circlip. You’re finished (pictured).