Need Help with driveshaft?

[jrdz2120]

I have a 72 long bed. I have gone thru 2 driveshaft support bearings in two months. The bearing just snaps off where it mounts to the frame. Has any one had the same problem? My truck has a 4/6 drop and I really don't feel any vibration when driving. Any sugestions?
Thanks.

[cdowns]

did the metal actually rip?or did it come apart where it's spotwelded together?
if it ripped than you should check to see if the shaft is bottoming out in the tranny tailahaft and you'd need to shorten it by about an inch
if its the spotwelds coming undone(fairly common) then weld it up solid b4 installing the next one

[neonlarry]

Two suggestions:
1. Get an adjustable track bar and center your rear axle.
2. Get one of these: http://www.iedls.com/page11.html
Also if you haven't done so already get a set of shock relocaters.

[dave2953]

x2 on the track bar.....I went through several center support bearings and eventually swapped to a one-piece. Although, a two-piece set up correctly can last a VERY long time. A lot of guys put additional welding on the bearings they buy because the spot welds pretty much suck. They seem to hold up much better from what I've seen on the board.

[jrdz2120]

This time the bearing came apart at the spot welds. Last time it acually ripped on one side of the metal, but was pretty old and rusty. It does have a modified driveshaft because it has a 700R4. I'll check to see if the yolk bottoms out on the tranny tailshaft and I wanna say the shaft looked as if it was sagging at the bearing when I installed the last one. I also have the panhard bar and shock relocators. I have maybe 500 miles on the truck since I got it so that may be the problem. Thanks.

[jostrans68]

i had the same issue it was my drive line was not clocked properly. do a search i found info on one of the forums good luck

[BigDaddyDave]

I've had 2 replaced in the past year,they just don't make stuff like the use too. My drive shaft was to long,the pinion angle was wrong,it was a real pain. For less than $300 the drive shaft was replaced,without the bearing and the pinion angle was set right. My truck has never driven this good. Save yourself a lot of time and money,and get rid of the bearing.

[truckdude239]

i had 2 break in a year i replace the last one almost a year and half ago no problems yet but i've put less them 200 miles on it need to make sure the shaft is balanced right or it will break

[Sport/Truck]

Originally Posted by jostrans68

i had the same issue it was my drive line was not clocked properly. do a search i found info on one of the forums good luck

Can you elaborate on this. I want to make sure I get mine correct.
s/t

[dave2953]

My guess is that he's referring to the u-joints being in phase, but I'm not sure.

[haysonj]

To be phased right both captured bearing cap at each end of the drive shaft should be in the same line. Can cause vibration if not phased right.

[ChevLoRay]

I've read magazines (Hot Rod, Car Craft, etc.) which addressed the phasing of the u-joints on a drive shaft. One of the things I remember had to do with the way the torque is applied to the u-joints as it is rotating. What they said, as I remember, is to be sure the zerk fitting is not under a load in the position it is in on the drive line. In other words, you don't want the force, or torque, to compress the grease fitting as you are accelerating. Supposedly, and I'm not about to argue with the experts, it could cause a weakness in the driveline.

Anybody have an experience with such a failure?