Eric, I have a little experience with the Zerks, as I had to remove mine to get to one of the fasteners when installing the driveshaft. They do thread in, so if you can unscrew the remains possibly with an EZout extraction tool or a left handed threaded drill bit. Replacements screw right in. Mine was a 3/16 socket I think, but it looks like yours did not leave much on the outside to use to unscrew.

The fun never really ends with these older beasts.

 

Precision 344's are the best 1300 UJ's but their grease fittings SUCK. I know having in the t makes them weaker - whatever I put a U joint with a cap fitting and a precision 344 and the one with the cap fitting blew up before the precision

Something similar to this, not sure on the sizing though TSC has a whole bunch similar if you have any near you All In One Grease Fitting Repair Tool for 1/8 in. NPT Fittings - 3952654 | Tractor Supply Company

that or go to harbor freight and look for "screw extraction kit" they have one that fits the sittings perfect

 

Very good example of why, when lubing one, you need to keep pumping the grease until you see new grease come from around all 4 seals.

First thing is to figure out why it broke off. Well, maybe second thing after removing the remains. I've never seen one hit, so I suspect it was maybe over torqued. Not enough to break at installation, but enough to stress it so it failed later.

 

It broke off because it didn't want to go in. I kept checking to make sure it was threading straight but it looked fine. Finally it just broke. I already tried a screw extractor but it just wouldn't bite and hold. I even tried hammering it in and then turning, but all it would do is drill a hole, ejecting soft aluminum like a drill bit. Then I tried hammering a torx bit in, but that wouldn't hold either.

I could probably let it use the lube it came for 3000 miles and change the joint then. If I tried to drill and tap it there'd be metal shaving on the inside mixed with any grease.

 

Warranty? Obviously you would have to do the labor but maybe get a replacement UJ for free.

I went to Napa yesterday and the guy just started typing in '94 Discovery' before I was three paces inside the door! That's sad. Point is, if you are on a first name basis with the parts guy like I am, they may give you some love on it. Good luck.

 

I wouldn't.
The "lube" that comes in u-joints is a rust inhibitor, not for use in service. That's why u-joints should always be well greased after installation, ideally before you install them.

You might get away with it, but why risk it?

 

Dang Tom I'm going to get way too good at rebuilding U-joints... Is it possible to pull the shaft apart in the middle so I don't have to unbolt the other end too?

I'll try the warranty and see what happens.

 

You should be able to. I can't remember if the D1 propshaft is keyed, so if you go that route, be sure to make it so the phasing is right when you put it back.

 

I would be reluctant to separate it in the middle Eric, it may seem easier, until it's time to put it back together, then you may be buying another entire driveshaft if that screws up on you.

Seems like you are determined to have the most fully rebuilt DI around. And in the shortest time frame as well.

 

OK I took the overwhelming advice not to split it. Ended up rebuilding both shafts and replacing the U-joint (again) who's zerk broke. Here's some cleaned and rebuilt propshaft ****: