JSM Posted November 22, 2008 Share Posted November 22, 2008 Drove my car today after a 2 week rest. In 1st and 2nd under hard acceleration the rear end, driver side, so it seems, felt like it lifted up, then wobbled? At first I thought the wheel fell off it. It was a very strange, never experienced before feeling. I went home, checked all 4 tires lugs and they were tight. I asked the wife to follow me and she said it looked like the car lifted a little in the rear and shuddered from behind. She said the wheels themselves never moved or wobbled themselves. Whats even stranger as I drove it more it happened less and less. I got home and checked the top strut nuts and the driver side were'nt really tight, more snug. I tightened those up and checked the other side. The car does have a sway bar. Stock R200 axles w/ a 3.90 rear end. Some after market springs, lowered about 1.5 to 2 inches. What else should I check? Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted November 22, 2008 Administrators Share Posted November 22, 2008 ....What else should I check? Gut reaction tells me one or both lower contorl arms are not fully attached to the car! Lower control arm attachment points and brackets. 1) Be sure ALL 4 bolts that attached the diff cross-member are present and tight. 2) Be sure all four bolts holding both rear lower control arm clamps are present and tight, (2 bolts per clamp). 3) Those rear control arm clamps are attached to a small cross-member. This small cross-member is attached to the vertical uprights just behind and on either side of the diff itself. Be sure this small cross-member is securely attached to the uprights, 4 bolts AND nuts, (2 per upright). 4) Those two vertical uprights attach to the car body. Be sure those uprights have all 4 bolts attaching them to the car body, (2 bolts each). Quote Link to comment Share on other sites More sharing options...
JSM Posted November 22, 2008 Author Share Posted November 22, 2008 Thanks Paul. I did check for their existance. I'll check how tight they are tomorrow. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted November 23, 2008 Share Posted November 23, 2008 A bound up or severely siezed u-joint in the half shafts might do this also. You might have a partially broken u-joint. Quote Link to comment Share on other sites More sharing options...
JSM Posted November 23, 2008 Author Share Posted November 23, 2008 A bound up or severely siezed u-joint in the half shafts might do this also. You might have a partially broken u-joint. It was strange. Mainly at the 4K to 7K range. Why would it only do it that high? Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted November 23, 2008 Share Posted November 23, 2008 It is engine RPM dependant and it exhibits itslef in the rear suspension? Strange? You could be stressing the part only in the powerband. Check the diff mounts too. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 23, 2008 Share Posted November 23, 2008 Also check the big bolts in the control arm at the inner pivot. The 24mm ones. Quote Link to comment Share on other sites More sharing options...
GRUMPZ Posted November 23, 2008 Share Posted November 23, 2008 when i removed the rear suspension i found areas where the bushings were had been "wobbled out". my personal opinion is a bad diff mount.I think I have all new bushings but I cut up the diff. mount and made a solid one. sold the diff but your welcome to first on any of the other stuff.I went to a solid axle. Quote Link to comment Share on other sites More sharing options...
JSM Posted December 8, 2008 Author Share Posted December 8, 2008 I think I checked everything today. Nothing, I even re-tightend most everything. What is strange is it stops once the car gets warmed up. I even checked tire pressure. I did notice cracking in the control arm bushings. If one or more is badly worn, could it cause the twisting I'm feeling? Quote Link to comment Share on other sites More sharing options...
timbo1jz Posted December 13, 2008 Share Posted December 13, 2008 almost sounds like a wheel bearing has failed. Your lug nuts will feel tight, but if a wheel bearing fails, I have seen it bad enough to where it feels like the wheel will fall off because the wheel will still be loose. Just jack up the car and get the wheels off the ground and move them a around to see if their is play in any of the bearings. I have seen this a lot. Quote Link to comment Share on other sites More sharing options...
JSM Posted December 13, 2008 Author Share Posted December 13, 2008 almost sounds like a wheel bearing has failed. Your lug nuts will feel tight, but if a wheel bearing fails, I have seen it bad enough to where it feels like the wheel will fall off because the wheel will still be loose. Just jack up the car and get the wheels off the ground and move them a around to see if their is play in any of the bearings. I have seen this a lot. I did that too when it was up in the air. Quote Link to comment Share on other sites More sharing options...
PETEW Posted December 13, 2008 Share Posted December 13, 2008 The thing that is puzzling me is you said it goes away when it warms up. I would think you have a bad wheel bearing ( I had really beat up fronts and there wasn't a ton of movement in the wheels), or a shot U joint. I would think it has to be something that can heat up with use. Let us know if you figure it out. Quote Link to comment Share on other sites More sharing options...
PETEW Posted December 13, 2008 Share Posted December 13, 2008 You know what, thinking about this some more, did you check your shocks. I had a weak shock on my truck and man would that thing shimmy. Only thing is, mine would get worse as I drove. Hmmmmm. Quote Link to comment Share on other sites More sharing options...
JSM Posted January 12, 2009 Author Share Posted January 12, 2009 You know what, thinking about this some more, did you check your shocks. I had a weak shock on my truck and man would that thing shimmy. Only thing is, mine would get worse as I drove. Hmmmmm. Driving this weekend I think it is the rear shocks. My thought is if there is a leak in one or low on oil the shock itself may perk up after it is used a little bit. This would explain why it goes away once the car is run for a bit. Am I wrong in this thinking? Thinking back to my R/C days when we ran low shock oil. The other thing I've noticed a lot more bounce in the back, but it his hard to tell from such stiff springs. Quote Link to comment Share on other sites More sharing options...
johnc Posted January 12, 2009 Share Posted January 12, 2009 Flat spots on the tires? Quote Link to comment Share on other sites More sharing options...
JSM Posted May 2, 2010 Author Share Posted May 2, 2010 (edited) Problem found and solved thanks to Chris Leon. He checked the car out before I sold it. He found that the rear driver side strut tube nut was loose about a quarter of an inch. Tightend it up and the hop / shudder went away under heavy accleration and so did the clunking! Completely makes sense now. Wish I would have taken it to him sooner for a look. The nice thing is I learned something. He hasn't posted in awhile, but his race car is coming along nicely. Edited May 2, 2010 by JSM Quote Link to comment Share on other sites More sharing options...
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