Driveshaft problems

[lukecp]

Today me and a friend went and put 3 new U-joints and a new carrier bearing in my '72 LWB. After putting everything together, we took it for a test run. Going down a paved road, it now vibrates REALLY bad. It is also makes a low, deep noise from the vibration. I think this is because when we took the driveshaft apart to put the carrier bearing in, we didn't put the to halves together in the same place as they were before, and this threw off the balance. Now i can barely drive the truck over 25mph. But the upside is that the U joints and carrier bearing fixed all of the problems with strange noises i was haveing before. So, how should i go about fixing this? Here is what i have though of so far:

1. Go to the junkyard and take my chances with a used driveshaft
2. Find a place that balances driveshafts (i doubt there is one around here)
3. I once heard that to balance a driveshat, you can squirt about 1/2 a tube of grease from a grease gun inside the tube, and it will balance it as you drive. It sounds like it might work, but i dunno if i want to try it or not.

Thanks for any help.

[cdowns]

check the yellow pages or ask at a local speed shop to find a place to balance the shaft

[sam's 72]

I would say just rotate the drive shaft. Pull the middle u joint and rotate the shaft, put it back together, keep doing this till it dont vibrate, you bound to get it back to where it was at. I dont know of any other way other then rebalanceing it, but you say there is not a place around you that does that. Are you sure this is the problem? You might want to check every thing out again, making sure all the clips are in good and tight, and that the rear joint is in the center of the ears on the yoke on the back.
Sam

[BigA]

Sounds like you have the drive shaft a 1/2 turn off. This happen to me once and could not drive over 25 mph as well. Question. Did you need any special tools to take the carrier support bearing off. I'm getting ready to change mine this weekend. Not sure if the yoke should just slide off. Thanks.

[lukecp]

BigA, i was just thinking about that. Would that happen if when putting the driveshaft back together, i accidently turned the driveshaft over at the center, and now one half is 180 degrees from where it should be? There were markings on the splines where we took off the carrier bearing, and they were matched up when i put them back on.

To change the bearing, drop your driveshaft out and take out the center U-joint. The yolk with the carrier bearing behind it will have a bolt holding it on. Put it in a vice and take out the bolt. The bearing is pressed on, and we beat mine off the redneck way (with a hammer ). Then put the new bearing on. To press it on, we put a piece of pipe on the metal part of the bearing where it meets the driveshaft, and drove it on with a hammer. Just make sure you mark everything so you don't have my problem. Also, it wouldn't be a bad idea to go ahead and put in new U-joints while you have the shaft out.

[BigA]

thanks, i give it try. Will let you know how it goes.

[Class of 69]

Yes, you could have the drive shaft out of faize. I recommend turning the pieces 180. All the u-joint caps should be in alignment when looking down the full length of the assembly. If turning it 180 will misalign it, only turn it till they align.

[jimfulco]

While you have it out, make sure all the u-joints are able to move around freely. If one is binding, it could cause vibration. If this is the case, whack the shoulders of the associated yokes lightly with a hammer. This usually frees them up.

[ckenwright]

I don't know what they charge in your area, but when I was in Albuquerque, NM I found a place that wanted $40 for balance and $20 per u-joints - parts and labor - if they had to change them.

[cruzn72]

I did not read all of the posts but make sure to take the carrier bearing in when you have them balance it. I forgot mine, had to go back and pull it causing an even longer delay. The shop that did mine painted arrows on the tubes to make alignment easier.

[chaptr2]

If you didn't do anything else but change u-joints and carrier bearing then you are just 180 out on your driveline alignment. Make sure the weights are matched up and your vibration will go away.

[lukecp]

Well, after getting home from work today (i babied the truck on backroads at 20mph...thank god i am only 4 miles from town), i yanked out the driveshaft again. I went ahead and switched it the other 180 degrees, and made sure all of the clips were in good, and got it ready to install again. It is now dark, so i will put the shaft back in tomorrow morning and see how it goes. Looking down the length of the shaft, the front two yolks look like they are in good alingment, but the back one looks like it may be a little out. However, i looked in the yellow pages, and sure enough, there is a place about 20 miles away from me that specilizes in driveline equipment. I just looked under "Drive Shafts" and there it was. So, if all else fails i will take the whole shaft down there for a balance.

Thanks for all the help so far

[lukecp]

Update:

Today i put the driveshaft in after switching the two halves 180 degrees. The truck dosen't vibrate anywhere near as much, and feels pretty safe up to 75mph. But, it still has a vibration. This may be because of rear tires that need to be replaced or balanced (they are almost burnt off ), or the driveshaft needs a balance. So, i will go ahead and get some new back tires, and if it still vibrates, i will take the shaft in to get balanced. The driveshaft shop said they would do it for $55.

[Class of 69]

If you didn't notice this vibration before the u-joint change, I suspect it's still driveshaft related. I suggest getting the driveshaft balanced first, so you don't take out your new carrier bearing, or trans bushing. It will still be 55.00 well spent!!