If the U-joint plug on the bottom side of the drive shaft would not screw in or if it did it wouldn't stay in, how would you fix that?
Try rethreading it with a 1/4 NPT
How big is the hole? And can you get stubby ended threaders because hypothetically, someone would not want to remove the universal joint just to rethread one hole.
it wouldnt stay in? meaning it was loose? if the threads are worn out then a tap will not fix it it, you either have to replace the missing material and rethread, drill and tap to a larger size, or possibly find a thread insert for whatever thread it is.
now if your threads are just boogered up and need straightening then a tap will work.
if you have to build it up, you would either weld or braze it, neither i would recomend doing in the car, JB weld is an option but i would catagorize it as temporary.
Had this problem with reproduction plugs before. None of them will fit the bottom hole, but will fit the top hole. I've lost 2 in the past. Tried screwing the repop bolt in and it flattens the threads every time.
The hole is threaded standard SAE Fine 1/2 x 20. Retap the hole with a bottom tap and put a Belville lock washer on the plug. It will thread in and stay in. You don't have to remove the driveshaft to fix the threads. ( Belville washers are available in the specialty washer boxes at most hardware stores. They are those almost flat washers with litte serrations across them that act as lock washers)
Stan,
Which Belleville Washer do you recommend? I found several variations available.
The threads on the bolt don't suggest being fine threads, but I will try what you said. I will reorder the plugs again and try.
They are less than 3 bucks apiece. I will locate a bottom tap from somewhere.
Will a NNF 1/2 x 20 bottom tap work?
Consider Nord-Lock washers. They'll work.
http://www.grampianfasteners.com/nordlock.aspx
http://www.youtube.com/watch?v=mgwmuZuJ02I
Went to my father in law's storage shed. Got the right re-threader. FIXED IT!!! Thanks.
William,
How could it be so simple? ;>)
How I fixed it...the father in law had a set of craftsman threaders, you know the kind that have a shank big enough for a socket on the end. He also had a set of nuts that would re-thread bolts. So, I cut new threads in the hole, and re-cut the threads on the plug cos they were flat.... and damn! Fixed! lol