: Suggestions to eliminate vibration over 50 mph on '93 FWB?



4cammer
04-16-09, 03:49 PM
Just got a '93 FWB 4 weeks ago. It needed new rotors and pads which were done. The front wheels were spun balanced yesterday. Still getting vibration starting just over 50 mph. Not that our roads are bad, but the only time I didn't notice it was on a lightly used country side road.

Thanks,

Skip

drmenard
04-16-09, 06:10 PM
what about your rear wheels...If it were mine and the car does not have posi rear... I would jack one rear tire off the ground , start it up , put it in drive and run it up to 30-35mph... no more .. an see if there is a vibration...do both sides one at a time keeping one wheel on the ground...watch the wheel and see if it bounces.... I have also seen when a brake drum have a small piece break off and throw it way out of balance..

4cammer
04-16-09, 06:45 PM
Thanks for the suggestion.

I should have said in my original post that the only vibration or shimmy that I notice is coming from the front end.

jey
04-16-09, 08:44 PM
Could be something loose/worn in the steering mechanism.

arnauts
04-16-09, 08:47 PM
It may help to examine your balljoints by jacking up on side of the car, and reefing on the rotor to see if it has excessive play. Put your car up onto ramps, and get a helper to shimmy the steering wheel back and forth a bit. Keep an eye on your centerlink, specifically where it contacts the pitman arm / idler arm. Examine the tie rod bushings where the contact the spindle also.

4cammer
04-16-09, 09:09 PM
I appreciate the help..thanks everyone.

Skip

jayoldschool
04-16-09, 10:56 PM
Check the idler arm and center link...

Cadillac Giovanni
04-17-09, 12:19 AM
My Brougham has a similar shimmy caused by a worn bushing where the drive shaft yoke fits into the transmission. Also might be u-joints.

96Fleetwood
04-17-09, 12:24 AM
Maybe the driveshaft needs to be rebalanced? Ever check the rear diff fluid?

jayoldschool
04-17-09, 10:17 AM
My Brougham has a similar shimmy caused by a worn bushing where the drive shaft yoke fits into the transmission

That is just a seal, and it is really easy (and cheap) to change. Let me know if you want more info...

Dcarlson
04-19-09, 02:35 PM
Check tires for cupping.

4cammer
04-19-09, 04:36 PM
Thanks everyone, I appreciate all the advice.

Hopefully its won't be one of those 'mystery' issues because I'm looking forward to experiencing the great cruisibility factor these cars have that I read about here so often.

Skip

Old Fleetwood
04-19-09, 10:07 PM
I have to think that 96 Fleetwood may be on the right track based on an experience I had many years ago.
The car was a Mercury Turnpike Cruiser with all the trimmings which rode like a bowl of cream at all speeds except at between 63 and 74 or thereabouts which was EXACTLY where I wanted to cruise.
It even smoothed out above 75, all the way up to 90 or better.
I went wacko checking out rims, tires, balance weights, and all that stuff until a buddy at the Mercury dealership put the car on the rack and had his fellow worker run the gas through the speed ranges while he watched from down below (with the rear axle jacked up so the drive shaft was at normal running angle).
The bottom line to all this was that one of the weights had come off the drive shaft. They sent the shaft out for rebalancing and all was well once more.
So, it's something to think about as a last resort.

steelybill
04-22-09, 12:45 AM
That bushing in the transmission tailshaft housing CAN cause front end shimmy. It's not just a seal, it's the bushing. The bushing can be worn and a bit loose without the seal leaking at all. Many folks have went through the process of tires, balancing, front end work etc, only to find a 4 buck bushing and a 2 buck seal to be the problem..

My wifes '93 Brougham had a drive shaft balance problem, and the factory has hose clamps on it to move around to get a balance. That's really a cheap-ass way to do something on a car like a Cadillac. And it wouldn't balance out even with those. I had the shaft balanced, and it still vibrated. The dealer had it up on the hoist, and we ran it there. The whole shaft had run-out. It still vibrates. A new shaft will be necessary to fix it. Those drive shafts are built here in Michigan at the Saginaw Steering Gear plant. How it ever got this far through manufacture and the dealer, is anyones guess. So much for an over-dressed Chevy Caprice. Not a very good car.

thefleetwoodguy
04-22-09, 06:59 PM
That bushing in the transmission tailshaft housing CAN cause front end shimmy. It's not just a seal, it's the bushing. The bushing can be worn and a bit loose without the seal leaking at all. Many folks have went through the process of tires, balancing, front end work etc, only to find a 4 buck bushing and a 2 buck seal to be the problem..

My wifes '93 Brougham had a drive shaft balance problem, and the factory has hose clamps on it to move around to get a balance. That's really a cheap-ass way to do something on a car like a Cadillac. And it wouldn't balance out even with those. I had the shaft balanced, and it still vibrated. The dealer had it up on the hoist, and we ran it there. The whole shaft had run-out. It still vibrates. A new shaft will be necessary to fix it. Those drive shafts are built here in Michigan at the Saginaw Steering Gear plant. How it ever got this far through manufacture and the dealer, is anyones guess. So much for an over-dressed Chevy Caprice. Not a very good car.

your saying the factory used a hose clamp and weight on the driveshaft???

or the dealer your using did??, I can assure you the factory never did that
I have taken 3 -93 fltwd brhms apart and NONE had anything mickey moused on the d/s,
the weight may have fallen off and that is/was a quick fix, but not FACTORY

the 93 although not LT1 powered was still a fine car, but like any car
depending on how it was cared for, could determine its fate

I know this is a Cadillac board, Im still a mopar guy!, but wouldnt have any other car but a 93-96 fleetwood brhm, for a daily driver,
not trying to start a pissing contest , but to imply the 93's were
just cheap Chevy stuff just isnt correct

also I have a nice factory drive shaft here if you need one

arivera
04-22-09, 09:06 PM
I have vibrations to on my 93. I was told it was my idler arm. When I get it taken care of, I'll let you guys know...

jayoldschool
04-22-09, 09:17 PM
The factory certainly did not use the hose clamp balance trick. They weld on little weights.

4cammer
04-22-09, 09:58 PM
Thanks everyone for the suggestions.

The car has been busy, so no chance to get it diagnosed yet, hopefully this weekend.