Koni STR.T (Orange) Nightmare...Dont buy these POS

[GonFern]

Hey guys,

Long time reader, first time writer. I picked up a 92 Vert M42 a few weeks ago. Body, top and interior are in great shape but mechanically it needed lots...almost everything. So after refreshing the engine oil seals, cooling system, sorting out some wiring, doing a z3 rack swap, new exhaust and a bunch of other misc. things, it was time to put the new suspension on and take it for a spin. I ordered a set of H&R Race and because budget is running up against the limit I set myself before buying the car, I chose to go cheap on the shocks. I figured Koni STR.T were new and would be a good replacement for the KYB that most people that cheap out on the billies or Koni adjustables, get.(mistake number 1)

Right off the bat, the Koni Orange Str.t struts didnt come with retaining sleves, you know, the collars that hold the inserts in the housing. Luckily my old ones were ok, so I reused them...so far not impressed. They also didnt fit in the factory upper mounts. The nuts are too large and you can't tighten them...even with special tool (which I have.) So after some research, i found out Boge had a larger diamater (32mm) upper mount (thanks R3v) so I order a set. Annoying delay, but nothing major.

THE BIG PROBLEM: Rear springs and shocks go in with new mounts like a dream. Fronts go on with the new Boge mount, new control arms and bushings, new sway bar links, set the car on the ground and take it for a drive. Right out of the garage, any minor suspension movement causes a loud clunk and bounce. WTF?? the struts are bottoming out!! After rechecking that all is tight, it does appear that these struts are giving me about 1/2" of travel and then they bottom out. In all of my years of working on cars, I have never seen this before. Even cheap struts will collapse completely- granted they will fail prematurely from working at the bottom of their range, but they don't bottom out with 4-5 inches of the rod still extended!

I'm at a loss. Today I will pull one back out and check the travel out of the car. For F*%&K sake! I knew I would be sacrificing longevity for cost, but I didnt expect this. Has anybody had similar experiences with any other Strut inserts?

Thanks,
-G

[TimeMachinE30]

HR race for a big drop and you chose OEM type strut like STRTs? What do you expect?

You need to reconsider your suspension. Sounds like you are going racecar. You should then match the spring with a better suited strut.

[GonFern]

HR race for a big drop and you chose OEM type strut like STRTs? What do you expect?

You need to reconsider your suspension. Sounds like you are going racecar. You should then match the spring with a better suited strut.

What I expected was a low ride height (H&R race have a higher compression, but actually dont lower the vehicle any more than HR Sports. I also expected a strut that would probably fail in a year or two due to the stress at working in the lowest range. I accepted that. What I didnt expect was a strut that bottoms out 4-5" before reaching full compression. No one else designs a strut that way. Even the Monroe junks that I took off fully compress into the housing and dont bottom out. I assumed Koni knew better.

[TimeMachinE30]

Seems you know best..
Return them.

[GonFern]

Thanks for the opinion. I shot an email to Koni. They are usually pretty good about customer service. I doubt Tire rack will take these back since they have been fitted. Its not an expensive mistake if they dont, but damn that money could have paid for a lot of misc. things I bought for this car. Some sites have listed that these are not applicable to the Vert...besides the smaller diameter of the top mounts, I cant see any other reason Vert struts are different. The only thing I can think of is that the new Boge mounts are physically taller than the originals, also adding to strut compression? No clue. Like I said. I have no idea why they would bottom out this far out. I'll have to take a close look when I get home.

[DRTSRFR]

Can you post some pics?

Can you confirm that both dampers are restricted in the compression stroke? ...or just one?

STR.Ts are very simple in construction. The only thing that will cause this is a piston/shim failure of some kind. There's nothing under the piston but fluid. That being said; either the shim stack is incorrect, or the piston itself is skewing when being compressed.

[GonFern]

Can you post some pics?

Can you confirm that both dampers are restricted in the compression stroke? ...or just one?

STR.Ts are very simple in construction. The only thing that will cause this is a piston/shim failure of some kind. There's nothing under the piston but fluid. That being said; either the shim stack is incorrect, or the piston itself is skewing when being compressed.

Thanks. This is just the type of response I was hoping for. I also found it hard to believe that there would be anything blocking the travel that far out. Honnestly I didnt pay too much attention to to the new shocks since besided the little niggle with the top mount, all looked about the same. I will take one back out today and see exactly what is happening. Both struts make the noise. I had my wife bounce the car while I checked for the noise and it is definitely from the strut assembly. Thats how bad the problem is, that a 115lb 5ft2 girl can compress the H&R Race springs to cause the clunk.

Koni has responded to my email with the expected suggestion that Race springs are too aggressive for the STR.T, but that they shouldn't be bottoming out with so little travel.

I will update when I have some more facts and get photos if I find anything definitive.

Thanks
G

[AndrewBird]

You put lowering spring on your car. You need struts with shorter shafts (like Koni SA or Bilstein Sport). The Konis you got are same length as stock and of course are going to bottom out.

[Andy.B]

It sounds to me like the struts might not be securely clamped in the housing. The most may not be the strut bottoming out, but lateral movement in the housing sd the suspension jounces.

When you get ready to take it apart, see if you can replicate the noise by pushing in and out on the top of the tire with the front end lifted up.

[GonFern]

So I got sucked into a late meeting and got home from work pretty late so I didn't get a chance to work on it. Just sat with a beer looking at it and cursing it. LoL. Another thought. Any chance that it may be normal? I mean I haven't driven the car more than out of the garage, up the bock and back. Any chance the springs are just settling into the hats? I tried to line them up and make sure the pads and hats seat in the right place...just trying to think optimistically. I also considered that it may be the shocks moving inside the housing since they are gas struts I didn't add oil to them but it seems unlikely. Those nuts are pretty damn tight.

[DRTSRFR]

There's no need for oil in the housings on a street car.

Are you sure you got the washers oriented correctly above the upper perches?

There's a pic in my sig of the orientation. If you leave the conical washer out it'll rattle like hell.

Loose inserts in the housings is a good thought also...

[GonFern]

There's no need for oil in the housings on a street car.

Are you sure you got the washers oriented correctly above the upper perches?

There's a pic in my sig of the orientation. If you leave the conical washer out it'll rattle like hell.

Loose inserts in the housings is a good thought also...

WOW. I know how difficult it can be to try to diagnose things over the internet...specially noise. You are an incredibly useful forum member...rather than the stereotype of flamers who just bicker about crap they read from other people. Your sig showed me that I actually had 2 problems.

Problem Number 1: I did leave out the washer between the upper mount and shock rod shoulder (the one with the big red arrow on your sig.lol) Kids, this is why you dont take and entire car apart and try to put it back 2 months later with all new parts without looking at diagrams. Cocky from my years of working on BMWs, I didnt organize everything well...pfft I know where everything goes....left out the washers. So that solved my loud clank sound going over slow speed cracks. But over slightly larger bumps, I still get a lower frequency thump.

Problem number 2: Remember I said these dampers dont come with with retaining nuts so I re-used the ones that were already on there? Well even when fully bottomed out, they still allowed the shock body to move in the housing. Went to BMW and coughed up the dough for 2 new factory ones. Now the car rides tight and quiet.

So as for my headlining statement, while "POS" may be a little harsh for these struts, as at the moment they work pretty well for a street application, the fact that the rod is a different size than stock and they dont come with noew retaining sleeve nuts, these shocks are hardly a bargain. The ideal is still to go for the Yellows or Billies, but if you must go cheap, at leas KYB is a complete kit and avoid BS problems like this.

Thanks for your suggestions everyone.

[DRTSRFR]

...glad I could help!

[AndrewBird]

That "conical washer" is actually just a dust shield for the bearing in the strut mount. It's only needed if the bearing isn't sealed. In fact, using it with sealed bearings might damage the seals.

HOWEVER, if you don't have enough spacers (washers) between the spring perch and the mount, the mount will interfere with the spring perch and cause problems. An extra washer will fix this. Large washers might also interfere with the mount. I just had this problem where the OD of the washer was hitting the crimps in the mount that hold the bearing in place.

Your nut problem doesn't make any sense either. Unless the threads protruded past the bottom of the nut somehow, it wouldn't have mattered what nuts you used. My guess is you just didn't get them tight enough the first time or maybe they were stripped out.