Hey everyone i just lowered my car with a used set of BC raincg coilovers.

They are really cool cept for this crazy annoying noise in the rear!!

It's a weird deep thumping sound everytime i go over any bumps.

I've taken out the spare, and the jack. Pretty much took out everything I can find out of the car and i still have this annoying thump.

Has anyone had any similar problems? And has anyone solved this problem???

I looked under neath my car yesterday too. Checked the muffler, and the bushings of the shocks everything looked fine....

 

It's not really a "deep thumping" - but once in a blue moon my rear seat will get caught in a weird place between upright and the recline setting, and it knocks around. I went nuts trying to figure out what was moving around back there. So that's something quick you can check, if only to rule it out.

Another possible culprit that I know of is your shock mounting - I'm not familiar with BC coilovers, but after you've made sure the top mount is tightened up to spec, check the lower shock mount. On my Endura-techs, the bottom shock bushing wasn't quite as wide as the stock one, so until I overtightened that bottom bolt to compress (i.e. bend) the shock mounting bracket, the shocks shifted around and knocked pretty loudly.

 

yeah its your bottom rear shock mount. dont compress it, just use washers. you will reply back very happy ^_^

 

hrm... i didn't mention the lower shock mount because the bushing was pretty wide... I actually had to take a hammer to the bushing to fit it in.

But I'll take a look at it again tonight just to make sure. =)

 

more info about it please!

 

The BC Racing coil over have 6 windings on the very short springs.... There just isn't enough room the individual coils to compress without binding together when going over bumps.

 

good point, but somehow i don't think that has anything to do with it because no matter how large or small the bump, unless the road is glass smooth I get this annoying thump.

But i'll take a look at that when i get under the car tonight.

thanks

 

The mounts would be the first thing to consider followed the preload adjustment,assuming there is preload and height adjustment on your coilovers..... If there is too much preload the binding could be the source of binding and if the is no preload there would be a chance that there would be a clunking sound on rebound.

 

fixed! it was the rear pass. side bottom mount, I took my 2 feet long bar and socket wrench and tightened it down.

Thanks alot guys! no more thumping sound!!!!!

 

GREAT... Now i have a new noise. it's a metal on metal noise. I installed a rear tower bar yesterday and now everytime between shifts i hear a metal clang noise...

I'm thinking that the strut is banging in with the metal hole thru the body...

anyone have similar problems?

 

Thanks guys. Tightening the right rear down from "tight" with a 3/8" ratchet to "pretty darn tight" with a 1/2" breakover did the trick on the thunky noise. Also checked the rubber isolators on the shaft and they were on right -- really I thought that would turn out to be my mistake.
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