Think I may have found vibration problem

after putting in the Schumacher mounts, which I was hoping would eliminate all the vibration I have been chasing for the last decade, took the car out sat. to the show and it was still there. It had changed but still there. I am sure the mounts helped the problem as the engine is in there straight now. But got to thinking that there must be something else I am missing here. New driveshaft and joints, new motor mounts, new poly mount in tranny. Then it hit me. TIRES. We had found a piece of wheel weight, the stick on kind about 2 " long on the garage floor. I pulled the rear wheels and sure enough saw where 2 weights had come off. So would that be enough to cause this vibration. So we jacked up the Dart Sport and took the tires off and put them on the Duster. It helped a lot.
The tires on there are new and balanced. So we checked the dates on my tires and they were made in 2003. Man how time flies. I am thinking that there may be something in the tire that is causing this too. Also by the drivetrain moving back about 1-1 1/2 inches in the car it probably changed the pinion angle some maybe enough to put it out of range. I noticed it got worse upon acceleration. So I am ordering a new set of B. F. Goodrich radial T/A's today and I am going to take this up to the spring shop this week and have my buddy check the pinion angle and set it like he did on the Dart. Then we will see what it is like .

chased a vibration in my 67 dart for-EVER. turned out I had rotated my axle tube in the housing (8.25, 4.10 rear). It eventually broke the rear companion flange. Dropped the rear out of the car and one of the leaf springs was pointing UP at a strange angle. Couldn't see it in the car but boy was it obvious once it was out.

Hope you got 'er fixed!


CE

I have found that out of balance tires cause a vibration around 50 mph and you can out run the vibration if you speed up. You might check that the rear u-joint is indexed into the yoke properly also. Had that problem in my race car.

2003 tires are going to be (relatively) very hard; the rubber slowly cures even as it sits. Using tires beyond 6-7-8 years old can be iffy.

that's what I am thinking. didn't seem like they were that old. but looking back I guess they are.

My dart was the same vibration at 50 , changed u joints and trans mount also .Never thinking of wheels and tires as they were all new , but one wheel was out .75/ corrected it .

70net440, u joints are new. driveshaft is new.