The car in question is a 1990 Honda Civic DX wagon. Current rear suspension specs are;

KYB AGX struts, set to 3, out of 4
coilovers with 275 lb/in rate springs
OEM lca's with Energy Suspension Poly bushings
Stock ride hieght

I just installed the rear suspension this past weekend, and while it definitely fixed up the squeaking/thumping problem I was having, the ride has gotten very bouncy. In some cases it's almost like riding on a trampoline.

I'm not sure what to do next, I wouldn't mind switching back to OEM springs, but I want to make sure that's the source of the problem before I take apart my whole rear suspension again.

Thanks in advance,

 

it sounds like the struts are blown.

 

you could test that

remove the suspension and seperate the springs and struts then take the struts and compress them with the top hats (don't push against the adjusters) and see if it slowly rebounds. If they don't rebound they're blown, if they do their good. It doesn't mean they're perfect though, they could still be worn and rebound. Do this with the settings at full soft

With 275lb springs you might be overdamping at the 3rd setting, try them at 1 or 2 of 4.

 

did you remove the dust boots completely?

 

overdamping wouldn't cause bounciness. at least to my knowledge. struts are probably blown if their set that high and its still bouncy. though i would try the forth setting just in case

 

I've been really busy lately, but I've got some spare time so I'm going to try fixing this again.

The struts are almost new KYB AGX's, and I tested them before installing so I know they're not blown.

Yes, BUT I replaced them with a KYB "universal" dust boot that includes a bump stop.

The fourth setting seems to have helped, I do still notice some bounce though, mostly over really beat up roads.

I'm going to go through the different settings on the shocks, start at 1, then 2, etc. Maybe the suspension just needed to setlle, but otherwise I'm looking at installing OE springs.