: Vibration Puzzle (Continued)



Timothy60
06-06-06, 12:06 AM
Vehicle: 1993 Cadillac Fleetwood 156,000 miles
Condition: Excellent
Problem: Annoying Vibration from 45 MPH---->72 MPH. After 72, it's smooth. Vibration is NOT affected by engine RPM, TCC engagement, tire inflation pressure, gear selection, brake application, road irregularities, or load.
What has been done so far:
1. front wheel bearings repacked and adjusted
2. front end components checked "OK" by two different garages
3. new tires on all 4 corners
4. driveshaft removed, balanced, new u-joints installed by driveline specialist

Now I am completely stumped as to what may be causing this vibration! There is SOMETHING on this Caddie that is rotating and is imbalanced. And it all started the day I had my snows removed. Does anybody have any new ideas? I've tried all your suggestions so far.

What does "on-car" tire balancing do? Does that have anything to do with some kind of a Holmes balancer that adds about 750 lbs of weight to the tires?

Can a brake disk cause an imbalance even though no pedal pulsation is felt?

Could a weight on some inner part of one of the wheels have dropped off?

As you can see, I'm just guessing at this point. Any thoughts?

VicVega
06-06-06, 01:37 PM
Must be a related post but I did not read it. I suspect somebody has curbed your car for you, meaning it slid on ice, snow or rain and slid sideways into a curb or other immovable object. When this happens the wheel or wheel flange or axle will bend slightly which will usually cause a vibration in the mph range you described. If this is the source of your vibration it should not be too tough to isolate. Is the vibration in the steering wheel or the seat. Steering wheel means the front seat means the back.

Usually its the back, but it can be either.

Either end you need to get the wheels off the ground and spin them on the car watching for wobble starting with the wheels working inward. If you see the wheel moving in and out sligthly you need to take it off and check the brake and the axle to be sure its not the wheel flange behind the brakes or the axle that is bent.

Balancing your wheels on the car will not address the problem. In my opinion, balancing wheels on the car which is supposed to balance the rotating assembly is just for show and their bill. This was done in the 60's and 70's because not all brake parts were balanced or would stay balanced, which is not the case today.

Good luck.

VV

WMD
06-06-06, 02:02 PM
Sorry to hear that you are still having vibration problems. If you are positive that it started the same day that you had your snow tires removed, you could reinstall them as an experiment if they are on rims. At the same time you could check your drums for a loss of a balance weight etc.
WMD

Junkman
06-06-06, 06:17 PM
There are a limited number of items that can cause this, and you have already addressed many of them. A last thought, since you believe this started the day that you had the snows removed, is that they over torqued the wheels when they were reinstalled and the rotors / hubs are not parallel. This is a long shot, but at this point, you are running out of possibilities. If the car doesn't have a posi in it, they you can jack up one side at a time and check the rear wheels by spinning them in drive. Don't go very fast and make sure that if the wheel were to drop to the ground, that there is nothing in the immediate area in front of the car that will get damaged. I would leave this to a professional to do. The front wheels you should be able to spin by hand and observe to see that they spin without distortion. Only other choice is to trade it and let someone else worry about the problem.... Junk..