Donnie Barnes wrote:
Yeah, it's more the ins and outs of how to safely tear a shock down (there's got to be a good way to take the gas pressure off) and how to put one back together. I see various tools listed for doing the high pressure charging, but you need to know what to charge them *with*.
If you are talking Koni Sports, if I am not mistaken, there are two types - hydraulic and gas charged. Both are twin-tube design, but the hydraulic needs no gas charge and the rebuild process should be similar to the process detailed in the link I gave for QA-1 rebuilds. While I am not sure what design Koni uses, there are generally two sub-types of twin-tube gas shocks - bag and emulsion. In emulsion, gas is forced directly into the damper outer chamber in order to reduce the likelihood of fluid cavitation through incrased pressure. Same theory as the radiator cap on the cooling system in your car. In bag shocks, the gas is contained in a sealed bag at a set pressure. The bag resides at the top of the outer chamber. Koni and most other twin-tube gas shock manufacturers that I have been able to find information on use nitrogen as the gas of choice. Koni specifies 4-8 bar of nitorgen pressure. If they are gas bag shocks, you won't need to do anything other than inspect the bag, and reinsert it. If they are emulsion, looking at Koni cutaways, I see no port for gas introduction, so I cannot even speculate what would need to be done. On monotubes, the bottom of the damper is equipped with a port in order to pressurize the are below the floating piston. Penske's are of this design, so if you read the link given for those, as I understand it, the rebuild process is different than what you will encounter with any twin-tube damper.
If you have an old and busted Koni gas damper, you might want to take it apart just to see. Of course, a conclusion based on one damper is not to be considered reliable, but it might give you some more information. On either twin-tube design, all you need to do is drill a small hole in the outer body to drain the oil. If gas pressure is still present, it will squirt out and make a mess, but it isn't dangerous. Interestingly, the directions Koni gives for disassembly of factory sealed dampers for the fitment of a Koni insert is the proper method for disassembly of a Koni as well
as long as you are not looking to put it back together.
Donnie Barnes wrote:
As an FYI, this is all brought about by the fact that I've *wanted* to do this in the past but never found a good enough reason. Finding a blown shock right before Nationals last year *should* have been my wakeup call, but it wasn't. Finding now that I may have another one only to find out Koni is currently over EIGHT WEEKS out on service requests might be the last straw.
--Donnie
Which, with all due respect, begs the question of why invest more time and money in Konis if they are so problematic? I understand it from a business point-of-view: the supply is great, the demand is strong and competition, in your experience, is poor. But for your own use, why not upgrade to better dampers? Far be it from me to tell you not to do this, I obviously have an interest in the subject and would relish the opportunity to see shock rebuilding and dynoing in person, but it strikes me as perhaps the most difficult way to solve the problem you are having.
Also, I forgot to mention, the Inside Racing Technology book I recommended before is not only about shocks. I think about 40 pages are on dampers. I don't want you to think that the whole book is dedicated to the subject. The rest of the book is worth reading, just not pertinent to your current project.
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