1951 strange vibrations

[jlerviti]

I'm not sure if this is the spot to post this or if anyone has any knowledge of my problem but I figure that it never hurts to ask.

I have a 1951 Chieftain Deluxe Eight. I've had it completely redone and now have it back. When I attain about 45 mph there is a low frequency vibration/humming that begins and gets louder as speed increases and can be felt throughout the car by all passengers. I see it in the mirrors as well. I thought I had read somewhere that the drive shaft should not be painted and the fellows that did the work put the black rust preventative on the entire undercarriage as well as the drive shaft. Could this be the source of that vibration? Would there be issues with an incorrect adjustment of the linkage for the transmission that would cause this? Any help would be appreciated, thank you.

[Larry]

First question is.... did it vibrate before the work was done? And when you say "completely redone" what do you mean? Engine? Drive train? Have the tires been changed?

The idea of not painting a driveshaft is a new one. Can you imagine how much paint you would have to put on- unevenly- to cause it to vibrate? You can check that of your list for sure.

Do a couple of tests. First, does it vibrate upon acceleration? When coasting? Continue when you take it out of gear? Do you feel it in the steering wheel?

You need to eliminate the tires first. If you can have the balance checked/redone, do so. If it still is the same, swap the fronts and rears to see if it changes at all.

From a quick glance, I'd be putting my money on the U-joints, but do the tests above first before tearing into them.

[jlerviti]

Thanks for the response, I discovered that the front U-joint had been incorrectly installed (done by a third party as part of the restoration). The bearings were too tightly pressed in causing them to bind. Unfortunately the vibrations ruined the rear seal to the transmission. It was a considerable job removing the original seal but the replacement was very easy. I did hate to lose the original seal, though, as it was performing quite well after 62 years.

[Larry]

It is usually a good bet to put your money on U-joints when there is a vibration. Glad it turned out to be a simple fix. My Dad had chased a vibration in his newly restored '36 Ford many years ago that turned out to be ill-fitting main bearings due to Old Henry having made available replacements for engines that they had rebored at the factory after screw-ups on the assembly line... the OD being changed (too big) while the ID was correct!

The old seal sure saw a respectable service life!