Vibration

[1957 Eldorado]

Hi there
I recently purchased a 1957 Eldorado. I had the car shipped from the east coast to the west coast. I drove the car to its new home which is approx 200 miles. The car drove as I expected fairly smooth , transmission was a little jerky , the front end is tight and the motor strong. A couple of immediate issues was the high idling and vibration at around 50 mph. Any thoughts on theses 2 concerns.
I'm hoping they are easy fixes eg, sticky linkage and unbalanced tires. I don't think the cat has been driven much in the last few years.
Thx

[Bill Balkie 24172]

Hello ,
  I had that same problem with a  1957 Eldorado Seville . Vibration at 50 mph . I replaced the carrier bearing and sent the drive shaft out to be balanced . That fixed my vibration Problem .

    Bill

[MY 59]

I would agree with Bill and get the tailshaft balanced

[Jon S]

To address the high idle - it could be sticking carburater linkage, a faulty dash pot or simply an over-adjusted idle speed screw

[Dave Shepherd]

I would suggest a little further  diagnosis before jumping into the drive shaft, check the center support for looseness as well as the "u" joints, make sure the shaft is not kinked or bent, look for a bent wheel or an out of round tire especially in the rear.

[Jon S]

I agree with Dave. It could even be an old tire with belt seperation not visable on the outside. I had 2 tires do that!

[n2caddies]

For cars I keep and drive I always replace the center support, bearing and u-joints then have the driveline assembly balanced. There is a world of difference on the stress on these old worn components when driven at highway speeds vs just around town.
Randy

[dplotkin]

Just remember that two peice drive shafts are more sensitive to pinion angle than straight ones and if you change ride height (or if ride height changes because of tired springs), it will vibrate at certain speeds and might change going up or down a hill or with luggage/passengers. With all due respect to the other posters above, I would first confirm your wheels/tires are balanced properly and then follow the shop manual instructions for adjusting pinion angle. I can just about guarantee you that if it is not in the wheels, tires or brake drums, its in the angle!

Dan

[LeRoy DeVol]

I agree with all the previous posts but have one more thing to add. I had the same problem with my 47 Cad. and the problem turned out to be the rear transmission mount. Over years the mount becomes soaked with oil & crushed with age and allows the trans. to rest on the frame & vibrate.

Lee DeVol

[Jay Friedman]

I had a vibration in my  '49 at about 50 mph which was cured with the drive shaft being rebuilt with new yokes, a new tube and new universal joints.