Hey guys,

I installed hks ls coils in the REAR only a few months ago. Ride was similar to stock, couldnt tell a difference in terms of ride harshness or better cornering...felt the same. However, a few weeks ago, my ride started feeling extra bouncy. I will go over a bump, and the car will(exaggerating here) sway left to right. I am driving down a long road, going 45/50, and when the road isn't perfectly flat and a bit bumpy, the car will bounce up and down and i hear a scrape from the rear. I am assuming this scrape sound is from the wheel touching something in the rear, don't think my rear bumper is low enough to scrape. Any small dip i go over while driving, the car will bounce and scrape. I don't know what could be the problem. Any input would be great. Thanks.

Btw, more info on my car to help better diagnose the problem:
Front suspension, completely stock and untouched.
Rear, only hks ls coils at stock height, no camber kit because I set the hat to spring height, or as close to it as I could. I am thinking maybe the hats weren't set identically, so there is bounce? I don't understand why I can hear the rear scrape when the ride is at stock.

 

Are they OEM style rear coils? if so, make sure the struts are set to the correct height of the sping... When I first installed my coils, I didn't like the rear height, so I decided to lower the rear a tad bit without lowering the strut accordingly... All I gotta say is that I felt like I was in my 78' Monte Carlo... LOLz... So I jacked up the rear and shortened the legnth on the struts and it rides perfectly smooth.... Btw, do you think your struts might be blown?

 

i felt the car had a slight bounce compared to any car ive drove stock, first i installed eibach pro kit loved the look, not the feel.. it felt like ****, now im on simple tein basic damper kit, and it feels great, im really low so im sorta bouncy but i love it everything is still tight i would assume? collars are at same height in rear? and yes what this guy said do think a strut is shot?

 

get an alignment and see if that helps?

 

hmm. well, if a strut is shot, isn't there supposed to be oil splattered nearby? i don't think it should be shot, its only been run on a car for less than 5k. i might have to check the strut height then. i just installed them without adjusting, i assumed the height of the strut was something you can't change.

 

cant do this on an HKS LS, they are only 1 way height adjustable (via the spring)

OP - your bumper cant scrape...its not nearly the lowest part of the car. Awfully hard to diagnose without being there, but the scraping can either be your tire rubbing the inner quarter panel lip, or even the top of the wheel well. Can be due to busted bump stops, or something more serious such as a blow damper that is now not able to control the spring. Only way to know is get the car in the air, look for leaks at the damper, and possibly remove them and try compressing them by hand to see if they rebound back. Even if no leaks are present, the dampers could very well be done and in need of a rebuilt (if they are rebuildable) or replacement (which will be impossible as that kit was discountinued years ago)

Bounce/oscillation in the suspension is a function of several key components interacting - most notably, your tires, the damper and the spring.

 

^^Thanks man, and everyone else. I will check this out with my mechanic, I don't have time to do this myself, nor do I want to lol

 

Sounds exactly like dampers. I doubt you can compress even shot ones with hand strength, though, so I don't know if that is the best way to tell.