Rear end clunking.
5th Gear Member
Joined: Jul 2007
Posts: 4,897
From: TX
Doogie65 - I won't guarantee but have a good guess that your issue is related to pinion angle. The relocation brackets move your roll center/axle alignment and will probably require a pinion adjustment. An adjustable upper CA would be my choice to get it adj right. I tried to get mine right with just the lower ca adjustments and never could get it perfect, which likely had something to do, again, with my one-piece driveshaft. Once I added an adjustable upper CA and got my pinion angle corrected (it's ~-3 now) everything has been fine. It was making some crrrraaazy noises back there before I corrected the pinion angle.
3rd Gear Member
Joined: Aug 2004
Posts: 505
From: Orange county, CA
Can somebody tell me if the clunking in stock form is normal? I get it sometimes with my clutch in while turning into my drive way (like a few clunks), also when shifting sometimes when I dont get it perfect do to the damn throttle dead space. I mean dont all the s197 have a sloppy drive shaft?
6th Gear Member
Joined: Feb 2007
Posts: 7,635
From: state of confusion
HI. I recently installed J&M lower controll arms ever since than I get a lot of clunking from the rear end. It happens when I shift and also if i am slowing down and hit the accelerator to speed up. Any ides or reccomendations would be greatly appreciated.
I had my torque wrench calibrated recently so i know I got the right tourque on the bolts (129 ft/lb) and the suspension was loaded when the bolts where tightened.
I had my torque wrench calibrated recently so i know I got the right tourque on the bolts (129 ft/lb) and the suspension was loaded when the bolts where tightened.
If they are, your bolt torque is compressing the poly instead of clamping the sleeve (which is what the 129 ft-lbs is supposed to be doing, minus just a little for rubber compression). When the suspension moves, so does the poly (slight rotation at first), and then everything slips a bit because the friction between the sleeves and the brackets is not high enough to resist it. When all of the slack is taken up, you get a clunk.
IIRC, there is also a spacer issue surrounding at least some of these things (another source of slack that gets taken up when the control arms are loaded from rest or loaded in the other direction). I know it's been discussed before, either here or perhaps in the Handling forum.
FWIW, poly bushings aren't like OE rubber bushings in that they do not require the suspension to be loaded while the bolts are being torqued (the poly will rotate more or less freely around the sleeve or at least the pivot bolt). But it wasn't wrong to torque them with the suspension loaded either.
Norm
Last edited by Norm Peterson; Oct 1, 2009 at 12:02 PM.
Thread Starter
1st Gear Member
Joined: Sep 2008
Posts: 74
From: New Hampshire
Did you happen to notice whether the poly bushings were longer than the sleeves that go inside them?
If they are, your bolt torque is compressing the poly instead of clamping the sleeve (which is what the 129 ft-lbs is supposed to be doing, minus just a little for rubber compression). When the suspension moves, so does the poly (slight rotation at first), and then everything slips a bit because the friction between the sleeves and the brackets is not high enough to resist it. When all of the slack is taken up, you get a clunk.
IIRC, there is also a spacer issue surrounding at least some of these things (another source of slack that gets taken up when the control arms are loaded from rest or loaded in the other direction). I know it's been discussed before, either here or perhaps in the Handling forum.
FWIW, poly bushings aren't like OE rubber bushings in that they do not require the suspension to be loaded while the bolts are being torqued (the poly will rotate more or less freely around the sleeve or at least the pivot bolt). But it wasn't wrong to torque them with the suspension loaded either.
Norm
If they are, your bolt torque is compressing the poly instead of clamping the sleeve (which is what the 129 ft-lbs is supposed to be doing, minus just a little for rubber compression). When the suspension moves, so does the poly (slight rotation at first), and then everything slips a bit because the friction between the sleeves and the brackets is not high enough to resist it. When all of the slack is taken up, you get a clunk.
IIRC, there is also a spacer issue surrounding at least some of these things (another source of slack that gets taken up when the control arms are loaded from rest or loaded in the other direction). I know it's been discussed before, either here or perhaps in the Handling forum.
FWIW, poly bushings aren't like OE rubber bushings in that they do not require the suspension to be loaded while the bolts are being torqued (the poly will rotate more or less freely around the sleeve or at least the pivot bolt). But it wasn't wrong to torque them with the suspension loaded either.
Norm
The end of the poly is slightly larger than the sleeave it sits in and the rubber is really compressed. I am going to see if the stock arms can be filled with flexane.
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