History-----installed 350/700r4combo, shortened front drive shaft got a "deal" $40.00 well it wasn't. Seats vibrated really bad to St. Paul and back. Take out drive shaft, take machine shop to be balanced found out how "good" the deal was --recut weld balance was out .030 new center brg. all is great. Vibration starts again check drive shaft with dial indicator seems good enough remove check things again-- end play in the center bearing. Noticed that the rubber bearing holder/mount is very stiff. May be to stiff not allowing shaft to move as diff goes up/dn. Looking at new bearing maybe putting slip joint into rear drive shaft???? Laurie
center bearing, pinion angle, u joint alignment , drive shaft in that order, and check that the bushing in the snout of the transmission was changed
Did they "time" the drive shafts when they welded it? Also if 2 piece drive shaft the u joints must be 180 when u couple them together.
" Some is good...more is better"
1962 Pontiac Parisienne Conv.
1926 Ford Model T Coupe ( Sold )
1972 VW Super Beetle Conv.
I AM AN X FRAME GUY AND GOING THROUGH THE SAME THING, SO I KNOW WHAT YOU ARE I N TOO !!!
63 Pariesienne sport coupe (The Big GTO), black, maroon interior, 409 4 speed; former owner of a 59 El Camino, 63 Corvette SWC, 62 Chev Bel Air SC.
Mahone Bay, NS Still not old enough to need an automatic
Prince Edward Island'64 Parisienne CS "barn find" - last on the road in '86 ... Owner Protection Plan booklet, original paint, original near-mint aqua interior, original aqua GM floor mats, original 283, factory posi, and original rust.
When we get driveline vibrations we tend to think that balance is the problem. On these particular X frame cars with the two piece shafts, 95% of the time the problem will be caused by improper angles or phasing.
Watch this video showing a simple one piece driveline...
You can see and hear why improper angles can cause a vibration.
On a normal single driveshaft, as long as the output shaft of the transmission and the pinion are parallel with each other, you're fine. It gets a lot more complicated when you add a center U joint,, and it gets REALLY complicated on a long wheelbase truck with two drive axles and three of four drive shafts.
The problem usually arises on these X frame cars if the transmission has been swapped for something different like a 700R4 or if the ride height has been changed quite a bit.
If you happen to have a digital level and a program like the Road Ranger Driveline Analyser, you can usually solve all your problems with a few well placed shims. If not, you have to do quite a bit of reading and research to figure out what you have to do in order to get the driveline right on.
Sometimes, the simplest way to make the problem go away is to shim the transmission or center bearing so that the two driveshafts are running without any angle at the center U joint. I mean the two driveshafts should be completely straight. Like this _ _ not like this_ / Then you only have the pinion and transmission output angles to worry about.
This is not the ideal setup because there will be no movement in the center U joint, which will cause it to wear out quicker than it should.
Once you have that, the normal way to do things is to have the pinion and the transmission output parallel with each other,,, BUT on these particular X frame cars, it's usually easier to use the "broken back" driveline arrangement. It's a little hard to explain but it works like this,,, if the driveshafts are sitting level to the ground,,, and the output shaft of the transmission is pointing down three degrees,,, then the pinion should also point down three degrees.
Here's a picture. The conventional setup is the one on the bottom but the less common broken back setup, top image will also work.
By the way, all of these settings should be done with the car at normal ride height.
409 powered 61 Poncho
best time 9.06@ 148
Just got drive shaft back, "New slip joint" looks nice! Put new bearing in center bearing assy. welded strap around it should work Pictures should come later if camera and photo program ae nice to me. I think photos are here ya!! 1st is the drive shaft then the center bearing after modification. Noticed that top round part with bearing was tilted to one side cut bottom to middle bent it over until it looked like bearing was centered over bolt holes then welded. Test it later when snow gone!! Now on to change springs again and speedometer correction. Laurie
Teich wrote:Pictures should come later if camera and photo program ae nice to me. Laurie
Pictures should come later if camera and photo program ae nice to me. Laurie
You got one of the poorly made ones. When I order them I usually ask them to bring in 2 or 3 and pick the best one. One had the plate on the bottom welded cockeyed, another, the spot welds let go while I was checking it out. What you have done is solid looking now, but it looks like its not standing up 90 degrees, but that could be my eyes or the angle of the photo. Check it for that before installing it. If its not straight, the bearing will be cockeyed in the rubber bushing and it will fail early.
Awesome tutorial Jim !
Teich wrote:This should work if not will look for billet one when at Back to the Fifties in June. Laurie
This should work if not will look for billet one when at Back to the Fifties in June. Laurie
I bought a billet one ... $125.00. They look too pretty to hide in the tunnel. I want to get a slip yoke put on the shaft also.
Yokes should be parallel