I have a MTX-4R and the shock designs are identical other than the rears are much longer for the MRX-4R. Lately, i've been building my shocks like every 2 weeks just because my car has seen alot of track time lately ( more like 12-15 hours a week of practice ). If your not praticing as much as I am, then I would build your shocks every two full race days. The things I usually do to rebuild my shocks are the following:
1) Inspect shock bladders. Just make sure that they have a nice firm feel to them and also inspect for tears around the neck of the bladder.
2) Polish shock shafts. I'll remove the piston and e-clips and polish the shock shafts with my dremel tool using Flitz polish. This will ensure for a very smooth shock stroke.
3) Inspect o-rings. I'll usually change out the o-rings every 6 months just to keep a nice seal on them. The mugen o-rings holds a nice seal for long time, but I figure since you're doing a rebuild, you might as well change them out. If the o-rings look good upon inspection ( no tears or areas of wears in the inner diameter ), then you should be all good. When placing the o-rings back into the lower portion of the shocks, use some associated green slime for the o-rings. This will ensure for a even smoother shock stroke and seal.
4) Inner shock casing. Once you remove all of the internals, i'll soak the shock bodies in some hot soapy water. I never use any kind of solvents to clean the insides of the shock body. The soap and water will do the job.
5) The piston should be all good, but sometimes i'll inspect the sides of the piston just to make sure that there are no burrs or areas of wear. This will prevent any side blowby.
Rebuild your shocks with mugen 600 ( equalivency to 55 wght ) and you should be ready to go out and have some fun with dialed shocks !! Hope this helps.
Last edited by Roger; 08-12-2007 at 01:47 PM.