Problems with 2001 Cadillac Seville SUSPENSION

Car vibrates considerably at highway speeds. this problem is of epidemic porportions. i fear that one of the suspension components will come apart on the freeway injuring multiple people in vicinity. dealership cannot diagnose or fix. *tr

I bought a cadillac seville from a used car dealer, it vibrate when i drive it. the whole car vibrates while driving it on a smooth road. the car dealer replace the tires, tie-rode, lower ball joints, and steering arm or something to that effect and done an alignment on all the wheels. it still is vibrating to this day. they say they can 't duplicate the vibration, and don't want to ride with me to show me what they are considering normal and i can show them what i am feel as abnormal. they even took it to at the cadillac dealer and they done some expensive machine balancing on the tires and it still does it. one mechanic said that i will have to wait until it gets worse to find out what it is or to get it fixed. that does not sound good to me at all. i don't know if there has been any injures or death related to this problem, however i don't want to the first. *nm

Dt: the caller said a nut came off the front lower ball joint. the caller's wife was backing out of a driveway and she heard a clung and when she looked the wheel was tilted out on the bottom. vehicle was towed to dealer who fixed it. manufacturer canceled the $50.00 deductible. *ak ses light illuminated on the dash. the dealer replaced the crankshaft position sensor. *nm

2001 cadillac seville sls tires vibrated at 19,00 miles and had a sign of a flat. *ts the tires were replaced three times. the lower control arms were replaced. *jb

Steering and front end vibrated when vehicle exceeds 63 mph. contacted dealer.they replaced 5 set of tires, and problem still occurred. *ak *tt

The vehicle had been to the dealership on 5 different occasions for front end vibration, the tires and rotors was replaced, however the vibration was still occurring. *ak *jb

Car was shaking while driving. they changed 9 tires to find the right match. still shaking at while driving. i was never notified of the problem. can u help me*ak (tiresize: dk)( dot number: tire size: dk )

When traveling 30 mph on highway, all four goodyear tires shake. there is a bad vibration. *ak 4 new controlled tires were installed that experienced the same vibration as the previous tires, so the dealer changed the tire brand to michelin and replaced the rotors due to pulsation, consumer states they have replaced a total of 21 tires and the problem still exists, possible suspension problem. hood was misaligned on the drivers side, dealer made adjustments. weatherstrip was not sealing and caused trunk to leak. ses light illuminated, dealer could not find problem. *jb