JCJimmyD

Ok haven't posted in awhile frankly because I haven't had any problems. Until now. The u joints in my front drive shaft when to ****. I pulled the drive shaft and replaced the u joints. I repacked the needle bearings in the flange and inspected the pressure spring. I put the new joints in and everything seemed fine. Until I got on the E way. At about 55 to 60mph the front end starts to shake. Just wondering if I need to get it rebalanced or what. It never did that before. I take the shaft out and run with no problems. I have no clue.

Bustedback

You may have it out of phase if you slid the front yoke off of the shaft.

JCJimmyD

Ok. So how do I correct the problem? This is the first time I've ever had to do a font drive shaft.

Bustedback

Make sure the u joint ears are inline at each end of the shaft. Here is a picture.

JCJimmyD

Ok so its just a minor adjustment then. I'll pull it back out tomorrow and have a look. Any chance that it might correct itself? Wishfull thinking. I know. Lol

Bustedback

Not a chance.

ZJMAX

when you assembled the double velocity joint did you get all the parts back in time with each other? Did you mark them to make sure they are all back in the same position?

Max

JCJimmyD

Yeah I marked all. I just took the shaft back out to have a look. The shaft looks to be inline. One of the cups fell off the forward u joint and I now have 2 broken needle bearings. Been fighting with this Damn thing for 2 months now. About ready to scrap it and start over.

JCJimmyD

If anybody out there has a good front drive shaft at a fair price I'd appreciate it.

dave1123

Okay, here's what happened to me. I've done so many u-joints in my life I figured I knew what I was doing and got complacent.

When I replaced the u-joints on my '97 ZJ's axles shafts, I removed the snap rings and used a BMF hammer to drive out the caps. They were quite rusty and took a lot of force to come out. I actually bent one of the flanges so the new snap ring wouldn't seat in the groove. I had to take it apart again and bend the flange back so that the dimension between the flanges was enough the seat the snap ring. Apparently I got the right flange to bend back because there was no vibration after I got it back together. Don't trash your shaft just yet, it can be saved.

On your front shaft, the u-joints need to be "in phase", that is the joint on the diff needs to be in the same rotational plane as the joint on the t/case. This is controlled by the way you put the spline joint back together. If that's not clear, look at it this way. If you lay the shaft flat on the floor so that the t/case u-joints are parallel with the floor, the front diff joint must be parallel with the floor also.

I built a driveshaft for a hot-rod truck once that needed to be a special length, shorter than original. I set the shaft up on a surface plate with a round bar thru the front joint cap holes resting on blocks of equal height. Then I did the same with the rear flange, rotating it until they were the same angle and dimension. After welding it together and installing it, I figured I'd need to balance it. After running 130 mph in the 1/4 mile, we had no vibration. I guess I did it right.

JCJimmyD

Ok Here's what I'm looking at. I'm pretty sure the u joints are now junk. All the grease heated up and seeped out past the seals. Not happy

dave1123

Looking at your picture, the front yoke and rear yoke are 90* out of phase. It's a wonder it didn't come apart! Split the slip joint apart and assemble it so the u-joints are pointing the same way. Then you'll have to replace the burnt out joints in the double-carden. The caps are blue from overheating so the temper is gone.

JCJimmyD

Are you talking about sliding the shaft out turning it 90 and sliding it back in? If so I'm gonna feel like such a dumb ***. Lol

dave1123

Yeah, that's what I'm talking about. It happens to the best of us. Ask me about the time I was wondering why my truck wouldn't start when I had the distributor rotor in my hand with my tools.

JCJimmyD

I've done that. Lol. Thanks man. Greatly appreciated. Lmao