Thump and Bump in the Rear
03-30-2010, 09:04 PM
#1
Thump and Bump in the Rear Ok... it's probably not what you're thinking, but then again... maybe it is.
A week or so ago, my '00 WS6 developed a rather obnoxious rub somewhere in the rear suspension. It only happens when I go over a patch in the road or a small speed bump. Both rear tires have to go over at the same time allowing the suspension to compress. If I go over bump diagonally, there's no rub/thump. It's most noticeable when I have a full tank of gas or some other load in the rear (no wise cracks). It's become progressively worse although it's hardly noticeable when I'm low on gas.
I have sub-frame connectors, LCAs, PHB, Konis, BMR springs, and LCA relocation brackets. They've all been on the car for well over a year with no prior problems. I thought at first maybe my exhaust came loose and was knocking against something, but had that checked today and it's snug and not rubbing a thing. So I'm back to looking at the suspension. BTW, there is no road rash on anything under the car, so nothing's smacking the highway. Oh... and my sway bar's snugged up and the bushings are good.
I'm going to re-torque the LCAs and PHB tomorrow and see what happens. I noticed that the PHB, which is adjustable, has a bit of corrosion on the QA1 fitting. Should I replace it?
Thanks for any suggestions,
Marc
A week or so ago, my '00 WS6 developed a rather obnoxious rub somewhere in the rear suspension. It only happens when I go over a patch in the road or a small speed bump. Both rear tires have to go over at the same time allowing the suspension to compress. If I go over bump diagonally, there's no rub/thump. It's most noticeable when I have a full tank of gas or some other load in the rear (no wise cracks). It's become progressively worse although it's hardly noticeable when I'm low on gas.
I have sub-frame connectors, LCAs, PHB, Konis, BMR springs, and LCA relocation brackets. They've all been on the car for well over a year with no prior problems. I thought at first maybe my exhaust came loose and was knocking against something, but had that checked today and it's snug and not rubbing a thing. So I'm back to looking at the suspension. BTW, there is no road rash on anything under the car, so nothing's smacking the highway. Oh... and my sway bar's snugged up and the bushings are good.
I'm going to re-torque the LCAs and PHB tomorrow and see what happens. I noticed that the PHB, which is adjustable, has a bit of corrosion on the QA1 fitting. Should I replace it?
Thanks for any suggestions,
Marc
03-31-2010, 08:23 PM
#3
I spent some time on an oil changing rack tonight and tightened up my LCAs/relocation brackets, PHB, and lower shock bolts. I did do away with a bunch of little squeaks and rattles, but the bump is still there.
The search continues...
06-24-2010, 08:08 PM
#4
SUCCESS!!!!!! 
I hate it when people post a problem, but then never post when they've resolved it. So, here it is.
The process of elimination finally paid off! Turned out it was the center of the damn rear swaybar rubbing up against my rearend girdle. I have an aftermarket LPW girdle and the company's logo is raised lettering that sits right on the bottom edge of the aluminum plate. The bottom left side (as you look from the rear) swaybar bracket had somehow rotated toward the front of the car. This pushed the center of the swaybar close to and almost up against the girdle. The more weight there was in the car, the more and harder it rubbed. Sometimes to the point where there was a distinct "BANG"!
I've rotated the bracket back to where it should be and if it stays put... I should be good. If not, I'll rotate it back and tack weld it in place.
I filled up the car shortly after fixing the issue and drove through a couple places where she'd been acting up. It didn't make a peep. I can't remember the last time I was this happy. This thing's been kicking my *** for months and it was staring me in the face the whole damn time.
Woot!!
I hate it when people post a problem, but then never post when they've resolved it. So, here it is.
The process of elimination finally paid off! Turned out it was the center of the damn rear swaybar rubbing up against my rearend girdle. I have an aftermarket LPW girdle and the company's logo is raised lettering that sits right on the bottom edge of the aluminum plate. The bottom left side (as you look from the rear) swaybar bracket had somehow rotated toward the front of the car. This pushed the center of the swaybar close to and almost up against the girdle. The more weight there was in the car, the more and harder it rubbed. Sometimes to the point where there was a distinct "BANG"!
I've rotated the bracket back to where it should be and if it stays put... I should be good. If not, I'll rotate it back and tack weld it in place.I filled up the car shortly after fixing the issue and drove through a couple places where she'd been acting up. It didn't make a peep. I can't remember the last time I was this happy. This thing's been kicking my *** for months and it was staring me in the face the whole damn time.
Woot!!