After H&R Race Spring Install - Popping Noise?

[MysticRob]

I installed the brand new race springs this weekend on all 4 corners along with H&R 1" spacers out back (and rolled the rear fenders), following these instructions:

http://1.cdn.lib.americanmuscle.com/files/99-04-cobra-hr-race-spring-install.pdf

I bolted everything back up according to the factory service manual torque specs, and took it for a drive but noticed a popping noise out back (that's the best description I can give) anytime the car leans left like during a right turn, and even when coming in or out of a relatively steep driveway while going straight.

My son says it sounds like it's coming from both sides of the rear when he's outside the car listening, but I'm not so sure. I'm using the stock top and bottom spring isolators, which are in great shape. I'm guessing it has something to do with the spring(s) decompressing and possibly hitting or dragging against something, but not really sure since no one else can drive the car, and I can't listen back there.

Took the wheels off to recheck torque specs and inspect everything, and I did notice the rear springs were extremely close to what I would call the inner fender lining (sheet metal between the springs and the tires) so I pried that out a bit and might have made the noise worse (or maybe it was just the springs settling more after driving that made it worse?).

Anyone else have this problem after installation of either the springs or the spacers (spacers are torqued to ~100 lbs/ft)? I seriously doubt it's the spacers though, since there isn't anything movable there. I can take them off later today just in case, but would rather not waste time chasing ghosts unless someone else can verify they've had the same problems with spacers.

Should I just wait for the car to settle more, or did I possibly goof something up on the IRS following AM's instructions (like lowering the rear diff after taking out the rear IRS bolts) the way it describes in their doc? There was no mention of which way to point the rear springs so I'm also wondering if maybe I have something mis-aligned with the way I put them in. Which way should the top and/or bottom of the springs sit? The fronts are easy since there's a lower pocket they fit into, but the rears are a mystery.

Any help greatly appreciated!

EDIT: BTW, the pic below is PRE-install. LOL

 

[MysticRob]

I finally found a good search word for thread --- "clunk"
This dug up some likely suspects such as the shock mounting hardware, among others, and a TSB# 03-9-5, which describes a fix, with pics below from this forum link:

Full Text Technical Service Bulletin

I'll check my car and report back with results to hopefully help others.

 

[CCS_56_EX]

I have the same symptoms after doing the spring install. It probably also did it to some extent before the spring swap, but I didn't notice it as I wasn't paying attention to check my work.

There are 2 pieces of sheet metal near both rear amplifier boxes that aren't welded together very well. I took a pair of pliers and slightly curled one of the sides of metal, and it made a substantial difference....it still makes an occasional pop if I make a real quick change in direction, or go over a speed bump, but is livable now.

 

[MysticRob]

... There are 2 pieces of sheet metal near both rear amplifier boxes that aren't welded together very well. I took a pair of pliers and slightly curled one of the sides of metal, and it made a substantial difference....it still makes an occasional pop if I make a real quick change in direction, or go over a speed bump, but is livable now.

I wonder if this applies to 'verts too, since the amps on mine are secured to the trunk floor behind the forward panel. I didn't really see anything else in the trunk after I removed all the panels but will pound on a few things and see what I can replicate.

EDIT: FYI, the coupes and 'verts are completely different in the trunk area so the known issues with panel warpage and/or popping won't occur on the 'verts.

I rechecked my work this evening and checked the items listed in the TSB and found the passenger side upper sway bar bolt loose. There are four total, two on each side (a lower and an upper), and all others were tight except that one. I'll take it off the jack stands and drive it tomorrow to see if that fixed the problem.

 

[CCS_56_EX]

See post #18 for pictures
http://www.svtperformance.com/forums/suspension-modifications-211/583410-rear-end-popping.html

Like you said though, your vert might be different.

 

[MysticRob]

Yeah, I saw that thread last night and actually printed the pics to compare and the 'verts definitely can't have that problem ---- the sheet metal is done completely different once they lop the tops off.

I finally figured it out though -- had a loose right side upper sway bar bolt so tightened it up and all is well. Also fixed the couple of trunk panels that had some noticeable cracks in them with some duct tape in the back. LOL