Koni Sports - Loose Centre Piston Rod Nut

[Fuyuzora]

So I had the first headache with my Konis yesterday... Now, I think the problem was due to installation rather than the shocks themselves (which have been rock solid) but here's the story all the same.

In the morning I went out to work, and the shocks were fantastic as usual. Didn't hit any potholes or other road hazards on the way there. On my way home however, I noticed an odd sound coming from the front/left shock. Vaguely like a rattle when going over bumps, but it was minor enough that I thought it might be my imagination. It seemed to persist to I figured I'd take a look tomorrow if it was still seemed off.

Later that night, I went out to meet up with a friend (I was driving) and over the course of the night the rattle became much more pronounced, and I became very concerned. Steering remained fine, no pulling, but it did not seem to be working correctly going over bumps and the rattle/knock sound was very noticeable. I decided I'd take it back to the garage that had performed the work today, if I wasn't able to diagnose it myself.

Jacked the car up and took the FL wheel off... Couldn't see anything wrong with any mechanical connections or the spring. Then I touched the shock - and it moved. WTF. Popped the hood and I saw this:

FRONT RIGHT SHOCK:
http://i51.photobucket.com/albums/f360/bairdga/Car/DSC_0893.jpg

FRONT LEFT SHOCK:
http://i51.photobucket.com/albums/f360/bairdga/Car/DSC_0894.jpg

... WTF. Clearly the nut has made its way up most of the threads on the top of the shock.

I tightened it down as best I could (which was a small amount as I don't have a 3/4" deep socket and the wrench I had available coudn't reach into the strut tower very well).

AFTER TIGHTENING:
http://i51.photobucket.com/albums/f360/bairdga/Car/DSC_0897.jpg

I did a quick loop around the block, and this seems to have been the issue (as expected). I'm going to pop out to Canadian Tire today/tonight and pick up a 3/4" deep socket and some locktite to finish the job.

Some questions for the forum~

- Why did it come loose? Is this normal for a firm shock over time?

- Was it simply an installation failure (forgot loctite maybe)?

- Are there any considerations I need to know when tightening down the centre rod nut? (I think I need to keep it perfectly centred from what I've read)

Advice/input appreciated as always. :thumbsup

[bluemazda3]

wow.. glad you got it solved... who installed the konis btw?

[Fuyuzora]

Install was done by Phil (tech) at Canadian Tire on Carling, in Ottawa. Before any "lulzCT" comments - Ralph (the service manager for this particular location) is active with the Motorsport Club of Ottawa and he (as well as the techs under him) is highly regarded by many auto clubs in the National Capital area. While I mentioned it as a possibility in the first post, I didn't/don't think that negligence was an issue, as I've been driving the car hard for the past month and it has been flawless until now.

At any rate, while I was at CT to pick up the deep socket and locktite, I popped by the garage and had a chance to speak with Phil, who came out to the car to see it and chat about the issue. He indicated that he has seen this before, wherein over time a shock will slowly work itself loose when subjected to heavy vibration. He also noted that while initial slip is quite minimal, as soon as it gains some travel it un-threads at a much higher rate. (which explains how this issue appeared suddenly and quickly progressively worsened)

On Phil's advice, I'm going to tighten down the main bolt until the shock doesn't travel/is firm. It has a relatively low torque spec so I'll have to be mindful of that. Will apply loctite to make sure it stays put. Another option is to add a second nut (and more loctite if desired) overtop to create a compression-stop. May go this route as it's cheap, easy, and should last well.

Only thing I need to be mindful of is the small interior nut (~8mm) which is connected to the interior of the shock, which will want to rotate with the main outer bolt. The small bolt should NOT be allowed to rotate.

[Aitch]

I had the same thing happen to one of the nuts on my Mazdaspeed shocks last year. Jimmy found the issue (wasn't quite as bad as yours and had gradually increased over a couple of months). He said that sometimes that does happen, may be to do with the initial torquing or it just came loose anyway.

[Fuyuzora]

Hmm, well I'm glad to hear I'm not the only one who's experienced this phenomenon (lol).

Are you still running just the one centre nut, Aitch? And it's held up just fine?

[2zoom]

Glad it was quick fix and also yourself and the car were not seriously injured..... :)

[Aitch]

Hmm, well I'm glad to hear I'm not the only one who's experienced this phenomenon (lol).

Are you still running just the one centre nut, Aitch? And it's held up just fine?

Yep, ran it that way for another year after the re-tightening and no issues until I sold the shocks recently.

[Fuyuzora]

Glad it was quick fix and also yourself and the car were not seriously injured..... :)

Thanks! That's definitely the most important thing. :thumbsup


Yep, ran it that way for another year after the re-tightening and no issues until I sold the shocks recently.

That's a relief. This evening I jacked up the car in order re-center the main bolt, then applied loctite to the threads and tightened down the main bolt properly (with the new deep socket). Went out for a little drive around town and the car seems to be back to normal now.

Still think I'll pick up two more nuts at some point (no homo!) to use as a compression fitting, though. Can't hurt to be too prepared.

[Strongjag]

Hey man, I actually had the same thing happen with some aftermarket shocks on an old car too. I just put a secondary nut with loctite (because of the low torque setting on the first one ) and it served me well for 2-3 years

[The Wolf]

:whoa Shouldn't they be using a lock nut or something similar for this? Seems like if it's a failry common problem, there would be a fairly common solution other than just keeping an eye on the situation.

I'd probably torque the nut properly, then throw a lock washer and another nut on top.

[TheMAN]

the nut doesn't appear to be a self locking nut... there's your answer

the stock ones are either nylon self locking nuts or has a form of thread locker compound in it... either one is always necessary for strut/shock installs

[Fuyuzora]

the nut doesn't appear to be a self locking nut... there's your answer

the stock ones are either nylon self locking nuts or has a form of thread locker compound in it... either one is always necessary for strut/shock installs

My dSLR was too awkward and the focal length too long to get a proper shot of it, but there's a split washer underneath the nut as well.

I cleaned up the threads and added blue threadlocker when I fixed it properly last night though. Still think I'll go with the double-nut approach though, as Strongjag and others mentioned.

TheMAN - You wouldn't happen to know the thread pitch for Koni Sports would you?

[TheMAN]

lock washers don't work nearly as good as loctite or nylon insert nuts at high torque since they get crushed

no idea on the thread pitch

[sol_searchin]

I had this issue also, just put a lock washer with another nut on top of the one you have on there now and you will be good to go, forever lol

[sammifan]

Old thread revival. I seem to have run into the same problem as OP over the weekend. I was at the cottage and had to take a rock path that wasn't very friendly to my suspension. Noticed some slight rattling the first day and got progressively louder throughout the weekend. I popped the hood and noticed not only was the center nut loosened to the point where there was only a few turns left before falling off :whoa, but the shock was also shifted slightly off center. I'll have to jack up the car and retighten the nut with loctite this time. Any idea what the torque specs are for this nut?

[sammifan]

Also, I'd like to add that I had been driving without problems for 4 years so I guess these nuts are prone to loosen by themselves?

[SomeGuy]

It will happen...I think it was shub that recently had this as well on his coils that we fixed up but they were very recently installed. I know it's not ideal but giving them a hit with an impact wrench carefully can solve the problem as they're tough to torque to spec. I guess the scary part is if that bolt lets go entirely, there's nothing stopping the front suspension from coming apart other than gravity.