I am making progress on my drive train restoration project and disassembled the drive shaft tonight. I have Chaffin's book for rear axles, but had a couple of questions about the parts I pulled out. In the book, the recommended wear on the u joint bearings is 0.0100-0.0200 inches - My best bearing is 0.017 and my worst is 0.027 - do you thing this is still usable, or should I buy a new one? Second, the threads on the end of the drive shaft are a little damaged - I was thinking of taking a die and trying to straighten out the threads - is this acceptable? I also noted that when I pulled out the drive shaft, the center portion was very rusty and pitted, is this common? The sleeve end of the shaft also has some score marks on it, but I am going to use a new sealed pinion bearing from Langs - I don't think this should effect it though. I apologize for so many questions, but this is my first time going through this process and I want to be sure everything is correct!
I will attempt an answer on the thread issue. If you have a die the correct size and thread, then I see no reason not to use it to clean up the threads. If you do NOT have a die, I would suggest a thread file. Thread files come with 8 different thread pitches on each one (4 on each end). They are easy to use, not very expensive, and fill a wide variety of thread size/problem needs. I have used mine many times with very good to excellent results on all types of thread problems.
Just a suggestion. Your mileage may vary (disclaimer).
That nut on the end of the drive shaft has to be torqued down hard so make sure those threads are good enough after you chase them. If you have any doubt get a new driveshaft. Also, make sure the shaft is not bent or you may have a vibration issue. Same is true for the u joint. Now is the time to get it right.
Rust on the shaft isn't really a problem.