Here's the story. I bought these Tein Street Basis coilovers brand new about 10 months ago. Driven it 8000 miles on the road under normal driving circumstances, never been taken to the track, and has always been driven locally. The road here in Orange County, CA is pretty good. I've never hit a pot hole or curb, or anything like that. Everything was good before 2 weeks ago, the piston rod that's connected to the vehicle's chassis snapped off. That said, pretty much the car FELL on the ground, as you all know, on our car, that piston rod is the only thing that supports and connects the suspension to the chassis.

I called Tein the next day, and explained the situation. The guy I spoke to on the phone told me that this is not commonly happen to Tein suspension (which I agree), and they have to take a look at it first before they can warranty it; since the coils is only 10 months old, it's still under warranty.

They sort of blamed it on the installation, claiming that "either it was over torque, or the top nut must have not tighten all the way when installed, creating a room for the suspension to play, and overtime, causing that bolt snapping off". This is the exact word I said: well, if it really wasn't tight enough, wouldn't it make clunking noise all the time? If there's a play, then there will be some kind of noise for sure. And there's no way that it was over torque, because there's not enough room for me to fit air gun to tighten that top nut. Plus,you can only tighten it so much before the piston rod spins while you turn the top bolt. And for the record, the coils was installed by a certified mechanic that have probably installed 1000+ coils with 0 problem. The guy stoked, and said nothing. He went around and explained me my option, whether I can get it rebuilt or buy a new one. Yeah, $400 for 1. Absurd!

I finally dropped off the coilovers yesterday, got it inspected. They want $168 for it, which is way better than $400, so I go ahead and paid for it. It still pisses me off how they can't warranty it, though. My question is: could this possibly a defect? I know it's not common, and it's probably the first time it happened, but there's always a first time for everything, right? What do you guys think?

Picture:
http://www.flickr.com/photos/ozoned/7983398332/http://www.flickr.com/photos/ozoned/7983398332/ by http://www.flickr.com/people/ozoned/, on Flickr

http://www.flickr.com/photos/ozoned/7983393123/http://www.flickr.com/photos/ozoned/7983393123/ by http://www.flickr.com/people/ozoned/, on Flickr

http://www.flickr.com/photos/ozoned/7983392591/http://www.flickr.com/photos/ozoned/7983392591/ by http://www.flickr.com/people/ozoned/, on Flickr

 

I can't believe that there wouldn't be damage to the threads on the shaft if it had been over torqued.... The nut would be concealing damaged threads so you'd need to place the the broken piece in a vise in order to turn the nut to expose the threads it is covering... If the nut at first doesn't easily turn it is very likely due to being over torqued... It is still hard to fathom a shaft that large breaking like it did.

 

impact gun?

metal specialists will be able to tell immediately if the metal was stretched by turning or fractured.

 

Not sure if I can remove the top nut, but I remember this: when the mechanic tighten the top nut, it can only be tighten so much before the piston rod turns altogether with the top nut. And impact gun is not possible, since there's barely room to fit my hand in it.

Just got off the phone with Tein, and now they accused the mechanic of over torquing it by using vice grip to hold the piston rod while tightening the top nut. I asked them to send me a picture, but they are still trying to find a perfect "angle" for the camera to be able to caught the scratches/damages from the vice grip on the piston rod. That said, the scratch is very minor -- which is not enough for them to prove that it was caused by vice grip.

 

If it was only tightened until the rod started spinning with the nut, then it wasn't tightened enough. That's weird if "a certified mechanic that have probably installed 1000+ coils" would make such a novice mistake.

It would have been loose and the suspension would have had too much play that could have stressed it over time. It doesn't have to make noise if it's loose.

 

Do you have any photos of the coilovers installed on the car, or of the front coilover that didn't snap? Both from the engine bay and from the wheel well? Just trying to see if anything was done incorrectly or if any of the required OEM hardware wasn't correctly re-used. If it was the installer's fault, you might want to try asking him to cover the cost.

 

i thought it broke at the inner nut that holds the strut mount (given that your spring is free in the pict above), not the nut that holds the entire strut to the car. There are 2 nuts on the shaft.