I have searched everywhere and cannot find an answer to my question. A little history on my car. I got my evo 9 with 60k on it running stock suspension. At about 85k my car started bouncing really bad when going over bumps at high speed (mainly the concrete bridges that are on the highways around here). So I found that the passenger strut was blown, basically by doing a bounce test. All other corners were fine. I pulled that suspension off and replaced it with another stock set I had laying around from a previous car. It was stock shocks and hotchkis springs. Fast forward to about 93k, I was sick of the hotchkis beating me to death so I pulled them off and disassembled them. I was going to use the good stock shock i had from the hotchkis setup and switch back to the stock suspension. When I broke down the bad stock strut assembly i found that the stock shock was so stiff that I could not compress it by hand. Kind of like air had got into the cylinder and will not let it compress. Which would explain the bouncy ride. I also discovered that the hotchkis setup had no bumpstops installed, which would explain the terrible ride.

So now I am back on a stock setup, just like I started out with. Except as of late my car has started bouncing again. This time its the driver side shock. Its so bad I am afraid to drive the car. Its like riding an galloping horse at 80mph.

So after all that, my question. What could be causing my struts to do this. I thought when struts went bad they are easily compressed and all the weight of the car rides on the spring, which would make a bouncy ride. Not in my case. I am going to replace it soon but would like to figure out what is causing the problem so I know the replacements wont develop the same problem.

 

I had a stock GSR strut go bad and it was on the passenger front. When it failed it got stiff. So, maybe the usual mode of failure.

 

I sent an email to KYB USA asking about what could cause something like this to happen but didn't really get anything useful back. Basically they said to check my coil spring and make sure there is a bumper and bellow installed. I was just wondering what could be failing inside the shock, like air getting in and causing it not compress. Oh well i guess it will remain a mystery.

 

If the damper seized just outside the range of the spring them maybe you're just bouncing around on a stiff metal rod?

Not sure if it's true or even relevant but a parts manager once told me that the tread wear can stay with a tire if it's be engrained into it enough. Have you checked your tires to verify if they've received any crazy wear pattern/cupping?

 

The tire is wearing as it should. Maybe the damper did seize. It can be compressed though when it is taken off the spring. When trying to compress it by hand it feels the same as if you are trying to force two opposing ends of a magnet together. You can push them together but as soon as you let go they shoot apart.

 

sounds like a standard gas filled strut to me.

 

I called KYB concerning my bad strut. The response I got was, "Something is broken inside." So, now you know.

 

Well a strut should be quite difficult to compress, usually requires body weight, can't do it with just your arms. And then it's supposed to extend on it's own.

 

I sent an email to KYB asking what they thought. They told me they didn't supply them, that I would have to call KYB Japan for replacements. I wasn't looking for replacements though, lol. I already have them. I never contacted them back because I really don't care anymore. i am just going to put the others on and hope that it doesn't happen again.



Also about the struts being hard to compress, they are. I can compress them if I put my weight on it and then when i let off they slowly decompress. The bad one could not be compressed all the way like the others. I barely got an inch putting all my weight on it like the others. Then when I let off it immediately shot back up before I could take my hand off.