Strange Vibration
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TECH Apprentice
Joined: Jun 2002
Posts: 301
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From: Fayetteville, NC
Strange Vibration This past weekend I helped a friend changed out bushings to polyurathane on his '98 Formula. We changed out his panhard bar bushings, torque arm, tranny, rear lower control arm bushings, and the end links front and rear. After lowering the car off of the rack he started getting a strange vibration. Espcially felt when trying to accelerate in a turn. It seems that it is mainly coming from the rear end area. Could over torqueing cause this vibration? If not does anyone have any ideas of why this is happening? It will also vibrate under acceleration in a straight away, just more noticable when turning and accelerating. Any help would be greatly appreciated.
Thank you advance
Thank you advance
Staging Lane
Joined: Dec 2001
Posts: 72
Likes: 0
From: Corpus Christi, Texas
Re: Strange Vibration Do you mean vibration with noise, or vibration without noise? Or both? Maybe there are 2 problems which makes it harder to figure out. I usually do one mod at a time, with a test drive in between to be careful.
Vibration plus noise is often the tranny touching the floor inside the trans tunnel. The poly tranny mount is a little too tall in some cases, if it is actually an LT1 mount but sold to you as an LS1 mount. Lower the trans crossmember with 4 fender washers between the chassis and the crossmember to check this idea out.
Vibration on turning without noise could be where the back end feels like it is orbitting eccentrically (like its on an ellipse instead of on an axis) which indicates a problem in the rear lower control arm bushings. Maybe the bushings weren't pressed in straight or maybe the arm got stretched out in pushing out the old bushings. Also, poly bushings here are not good for corners any way, because they resist the native twisting of a straight axle on corners. You might substitute some 1LE arms which are about $70 a pair to check it out.
I am guessing that you know that the suspension must be loaded when you final torque the LCA's to prevent squeaking, and that you only did one LCA at a time so the axle doesn't twist.
Vibration plus noise is often the tranny touching the floor inside the trans tunnel. The poly tranny mount is a little too tall in some cases, if it is actually an LT1 mount but sold to you as an LS1 mount. Lower the trans crossmember with 4 fender washers between the chassis and the crossmember to check this idea out.
Vibration on turning without noise could be where the back end feels like it is orbitting eccentrically (like its on an ellipse instead of on an axis) which indicates a problem in the rear lower control arm bushings. Maybe the bushings weren't pressed in straight or maybe the arm got stretched out in pushing out the old bushings. Also, poly bushings here are not good for corners any way, because they resist the native twisting of a straight axle on corners. You might substitute some 1LE arms which are about $70 a pair to check it out.
I am guessing that you know that the suspension must be loaded when you final torque the LCA's to prevent squeaking, and that you only did one LCA at a time so the axle doesn't twist.
Launching!
Joined: Jun 2002
Posts: 286
Likes: 0
From: Abilene, Tx
Re: Strange Vibration Thank you for your input. This was my car that we did the install to. I know next to nothing about suspension, so going into this I really did not know what to expect. The vibration is a vibration with no noise. I also noticed today that when I do a hard reverse acceleration I also get wheel hop, bad! No I did not do one LCA at a time either, if that is the problem, what can I do to fix it? I will probably look into getting some new control arms here pretty soon to though. I am open to any more ideas and any help would be greatly appreciated. Thanks!
<small>[ September 30, 2002, 09:01 AM: Message edited by: BriGuy ]</small>
<small>[ September 30, 2002, 09:01 AM: Message edited by: BriGuy ]</small>
