Whats wrong now

[ss409cid]

Thought I would cure a couple of problems on the ole 62 09, but I seemed to have created another.
Old rear springs were shot, so I installed new ones, installed new drive shaft center support bearing at same time. now the drive shaft hits the tunnel when under power.:confused:
It appears that the shaft is riding pretty high in the tunnel, could I have gotten the wrong bearing? It appeared the same, but I made no measurements and the old one is gone. Or could the changed ride height , about 2 1/2 inches, of the rear of the car due to new springs be a factor. What do you guys think???..........Thanks Larry

[jim_ss409]

If you look at a shop manual for these X frame cars you'll see that there are about 5 pages devoted to driveshaft alignment. Changing the ride hight above the stock level will change the driveline angles. If they are far enough out there will be a tendancy for the shaft to whip at the centre joint. The stock rubber hanger bearing will alow it to move quite a bit, maybe enough to contact the tunnel. If you are getting a harsh vibration at low speeds under full throttle, around 10 to 20 mph, it's a good bet that your driveshaft angles are out by a fair bit. Another thing to check, if you are getting a vibration, is the phasing of the driveshaft, the way the U joints line up. The manual will cover it if you've got one. I can measure the height of the centre suport bearing on my 62, it's out of the car, and post that tonight. I've noticed that the shaft of my 62 just touches the tunnel when the car is jacked up and the rear axle is hanging on the fully extended shocks so if your car sit pretty high in the rear it might be close to hitting.

[jester]

Hello Jim. How do I get a copy of a shop manual?

[SS425HP]

I would think raising the ride height would make it more prone to hit the bottom of the tunnel. You say it's hitting on the top of the tunnel? To hit the top, the pinion angle would have to be way up. Is it rotating a lot? Is something loose to let it rotate this much? As stated above, get the manual out and check your drive line angles. Something is sure wrong to cause this, and you need to get it fixed.

Fred

[jim_ss409]

I measured the centre suport on my 62 it's about 3 1/2" from the base to the centre of the bearing and about 5 3/4" tall overall. I was just thinking about another possible cause. I have two driveshafts and one of them has two saucer shaped plates on either side of the centre bearing. They are attached to and spin with driveshaft. If they were to contact the outer portion of the bearing support they would make alot of noise. Since there is no sliding yoke on the rear shaft the bearing gets pushed back and forth in the rubber when you hit bumps. This is why it's best to install the driveshaft with the weight on the rear suspension.
The shop manuals are available from any of the places like Late Great Chevys or Showcars etc. Check the links on this site for web addresses. They are really handy to have but they cost a few bucks and for 62 you have to get two of them, the 61 master and the 62 suppliment.