Fox Performance Series Shock Rebuild Thread
- Thread starter Mike_H
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Agreed. We'd love for Mike to join our support group. Meetings are at 6:30pm on the third Thursday of the month...It's a sickness
Yeah. I put a stack in them that was different from what they came with. Who knows if it will be in the ballpark, but I made the best guess I could.
Looking forward to your results. Could you share what you did and why after you have them installed?
I could but I really don't think its gonna help anyone other than me. Shock valving is SO subjective to the user and the rig its going on. I really don't want to post my particular shim stack, because I don't want any one to think that it would work, as is, for them.
As far as why...That is just kind of a guess based on a dumb amount of reading I've done. I know what WAS in them and the application they came from (JKU unlimited). Front weight is probably approximately the same, so I stuck pretty close to what they were valved originally, just a couple thinner shims on the bigger end of the pyramid (since I like a little softer ride for the small, chattery stuff). The rear shocks had a lot going on, so I basically simplified it. They had two crossovers on compression and one on rebound. I rebuilt the stack with one crossover on compression (flutter stack). I also picked thinner shims, just because I know my TJ has a lot less weight on the rear shocks than a JK will.
I have No Idea if it will work. They are pretty easy to change and I have a few extra shims around to play with if I hate it.
Edit: I've found quite a bit of info over on race-desert.com. Its another forum, and there are some tuners in there that offer advice on set-ups. Lots of coilover talk.
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There are quite a few of us, so we have local chapters everywhere. Someone from the Kent County chapter will be in touch soon.
I'm not looking to copy what you are doing,that would indeed be useless.just to see what your impressions are after particular changes.
Thanks for sharing your thoughts,and the link to tuning discussions! That could be useful to someone wanting to mess around with valving.
They were definitely small, but for that small size they had pretty high speed and frequency of vertical piston travel, and as I understood them relied heavily on small ports. They were pressurized air springs atop an open bath oil damper. They were heavily prone to air/oil mixing back then too. Those early 90s MTB shocks like the Mag21 were a huge step forward from rigid forks, but they really had alot of problems. Probably made worse by a suggestion to do a 200 hour service interval. Modern forks and rear shocks have like 20-40 hour service intervals, though the damper cartridges within are sealed and effectively unserviceable.
I can try to post something when I get them mounted and have some seat of the pants feels. Until now, all of my "shock tuning experience" is keyboard based! I have tried a BUNCH (basically all) of the aftermarket bolt in shocks in my jeep though, so I do know what I don't like. I also know I want to use all the travel available, so I will keep going softer until I do, or it gets "floppy" on roll/sway. I'm not hooning my Jeep through the desert either, so I'm not going to tune for jumping off a 3' ledge. If I can make it less chattery on small events, use 75% or so travel on the street and make it ride nice and controlled over the rocks and roots that we have here in MI trails, I'll be happy. I think back to a trip I took to drummond...That trip I had the well regarded Rancho 5000x shocks and they were absolutely terrible. The trails there consist of stones...like 12" diameter cobble stones, but in a gravel matrix. They are ROUGH...and my teeth were chattering, even in 4-low and third gear (so like 10 mph). I think I will get some nice valving, eventually...I just don't know how many thousands of dollars I'll have to invest in shims, LOL. The conflating this is that I have a pro tuned set of the Racing series ready to go, just waiting on me to get enough time to do a frame swap. So...how much time do I really spend optimizing these?
Unsure if I should continue this thread with those findings/ideas or post a separate thread. I'm also unsure if I have the patience to deal with the inevitable BS that is bound to come with the ensuing discussion.
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A wise consideration, my friend! Shock tuning is more subjective than not, and there are plenty of worms in that can...
So long as it is kept within that context it could be a good read,to me at least.
If you try to deal in absolutes,you'll absolutely have the headache of someone trying to tell you what that is.
If you consider that anyone looking to run tuned shocks is in a tiny little minority which is viewed by the majority as being holier than thou and more than a bit elitist, not only is there plenty of worms in that can, it ain't exactly a little can.
Shocks are re-assembled. Painted them over the last couple days. I should have hit them with some Epoxy clear...I didn't realize how much the shock oil would soften the paint I used. Its not the end of the world, but I definitely felt the paint get a little tacky everywhere the oil went (and its impossible to fill and bleed them without making a mess). I supposed I could hit them with clear now...since I'll probably need to pull them apart again to change shims.
Also had to spend a little more money. I really didn't like how much corrosion there was on one of the post mounts (like for the front upper mount), so I did some DEEP internet research and found out they are replaceable. Not super easy to find, but they are available (241-02-050 and 072, if you're so inclined). Takes a bit of heat to get them out, since they poured about a cup of red locktite into the threaded pocket in the shock body too. Anyway...The offending posts.
The one on the left was the one I was really worried about. These are 2-5/8" long. I replaced them with 3" long ones, since the shorter ones were pretty hard to find. Anywhere I did find them, they only had one in stock. They were 17 bucks, each...but I can't make em for that. So, add another 34 dollars to my spreadsheet.
Here are the shocks, fully assembled and ready for a nitrogen charge.
and a close up of the Schrader valve mod I did. I really don't know why they put that dumb pellet system in these, other than to dissuade the "general public" from hooking up a gas station air line to their shocks and letting all the nitrogen out.
Pretty happy with how these turned out. For what I have into them, it was definitely worth the time. I would have spent 200, min, on new shocks anyway, and had garbage. These are decent. They are not as good as factory race series, but they are still pretty well built. The ONE thing I think I'd do differently is put the factory race IFP in. The stock ones are plastic and use an O-ring seal. They have about 1-1/2 threads of a 10-24 screw in the center of them (which is how you're supposed to pull them out of the reservoirs and set their starting position). I stripped every one. The O-ring has quite a bit of stick-sion (resistance to start moving). The Factory Race IFPs are aluminum and use the brown turcite bands to seal. They also have a 1/4-28 thread in them of proper depth to actually thread a screw in and pull them out/set their position. They move much more easily, with resistance to start. Overall, just a much better design. The bores on the performance series vs the Factory race are the same, so the parts would interchange easily...just at a cost.
Next up...Install. Deer hunting season is upon us though, so I'm not exactly sure when I'll get around to that. I did find these from Iron Rock Offroad, to help with the Bar pin vs shock eye up front (and the rear Bar pin from the JK shocks is too wide for the TJ, I believe). This will help save some time when it comes to mounting (as long as the lengths work out).
https://www.ironrockoffroad.com/product/bar-pin-eliminator-pro-xjtj-rear.html
https://www.ironrockoffroad.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=16085
Also had to spend a little more money. I really didn't like how much corrosion there was on one of the post mounts (like for the front upper mount), so I did some DEEP internet research and found out they are replaceable. Not super easy to find, but they are available (241-02-050 and 072, if you're so inclined). Takes a bit of heat to get them out, since they poured about a cup of red locktite into the threaded pocket in the shock body too. Anyway...The offending posts.
The one on the left was the one I was really worried about. These are 2-5/8" long. I replaced them with 3" long ones, since the shorter ones were pretty hard to find. Anywhere I did find them, they only had one in stock. They were 17 bucks, each...but I can't make em for that. So, add another 34 dollars to my spreadsheet.
Here are the shocks, fully assembled and ready for a nitrogen charge.
and a close up of the Schrader valve mod I did. I really don't know why they put that dumb pellet system in these, other than to dissuade the "general public" from hooking up a gas station air line to their shocks and letting all the nitrogen out.
Pretty happy with how these turned out. For what I have into them, it was definitely worth the time. I would have spent 200, min, on new shocks anyway, and had garbage. These are decent. They are not as good as factory race series, but they are still pretty well built. The ONE thing I think I'd do differently is put the factory race IFP in. The stock ones are plastic and use an O-ring seal. They have about 1-1/2 threads of a 10-24 screw in the center of them (which is how you're supposed to pull them out of the reservoirs and set their starting position). I stripped every one. The O-ring has quite a bit of stick-sion (resistance to start moving). The Factory Race IFPs are aluminum and use the brown turcite bands to seal. They also have a 1/4-28 thread in them of proper depth to actually thread a screw in and pull them out/set their position. They move much more easily, with resistance to start. Overall, just a much better design. The bores on the performance series vs the Factory race are the same, so the parts would interchange easily...just at a cost.
Next up...Install. Deer hunting season is upon us though, so I'm not exactly sure when I'll get around to that. I did find these from Iron Rock Offroad, to help with the Bar pin vs shock eye up front (and the rear Bar pin from the JK shocks is too wide for the TJ, I believe). This will help save some time when it comes to mounting (as long as the lengths work out).
https://www.ironrockoffroad.com/product/bar-pin-eliminator-pro-xjtj-rear.html
https://www.ironrockoffroad.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=16085
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