I've had a few stubborn u joints my self, but nothing the gas ax couldn't handle... lol

 

you know the #1 penetrating fluid is oil of wintergreen but that stuff is hard to get ahold of. the navy uses it a lot. if it works on bolts rusted by seawater for years then i think it would work on any land locked bolt. my dad used it when he was in the navy and now a days its kept under lock and key on the ships because its toxic. my dad told me a while back that to break a bolt loose all you had to do was put a couple drops of that stuff on it.

programmertim-- one thing i didn't think of is CRC Freezeoff. you say you heated it but if you heated the whole thing then it would expand the cap along with yoke. you could get the yoke warm (just warm enough to be too hot to touch but not near glowing) then spray the freezeoff on the cap and it may come apart if you press it right away. oreilleys has the freezeoff stuff.

d_sinsley-- good luck with the rears, i can't seem to ever do mine without pinching my hand with the pliers and getting a nice blood blister. i still have rough skin under my pinky where my hand is still healing from recently doing my drums.

 

I finally got it off. I think the shock load did it. I put it in the vise and got it as tight as I could and then beat on it with the sledge. It didn't do any good. But I left it clamped up over night and hit it again in the morning. It broke loose on the second hit.

When trying to press back the other way to get the other side out, I couldn't get the cap to go in straight. It (actually both, as it happened on each pair) bound in the ears and I could see it raising a burr. Eventually, the joint broke through the cap instead of pressing the cap out. That gave me enough room to get the joint out completely and then tap the rest of the broken cap out to the inside. I filed down the burr and put it all back together and no problems since.

Now, yesterday I started on the right hand side. It wasn't as bad, and I needed the truck, so I haven't had a chance to get back to it until this week. I was clamping it all up in the vice like I did last time, getting ready to bang on it and let it sit, when I heard a pop and it loosened up. I couldn't see that the caps had moved or anything, though. I put it back in and started tightening it down and heard another pop and the fixed jaw on the vice wasn't fixed anymore. I broke it off the base. Now, I guess I can't really vouch for quality on the vice. It was the biggest one Lowes had, but it was Lowes after all. Anyway, I took the shaft to Firestone and had them press it out. It didn't seem to give him any problem. I'm wondering if it is because he had an impact hammer on the press and it was back down to the shock load thing.

Anyway, that is all back together, but I need to replace the upper ball joint on that side as well. I'll probably start another thread for that.

 

i changed my axle seals a while back and when i went to change the u joint since it was out already and greaseless on two of the caps i kinda screwed up a little bit. i pushed the u joints cap all the way through the yoke and couldn't get it to go back in so i could get it off so here is what i did.

4 1/2" angle grinder to cut one ear off and the dremel to cut the cap off the other side.

if you ever run into another stuck u joint then you can cut it off and drill a hole in the center of the cap before putting it on the vise. having an empty cap with a hole in it should take enough tension off so that it will pop right out.

 

If I am understanding right, you were trying to get the old joint off, and pushed the joint too far, leaving one cap outside (the one you were trying to remove) and the opposite cap, the one you were pushing on, completely inside the yoke. With that line-up, you couldn't get the joint free because the cap doesn't give you enough free space. And you couldn't get the cap to go back in the hole it came out of?

That is exactly what I did, and I didn't know you were supposed to do it another way. I couldn't see the cap I was pressing out, because it was inside the socket, but I ***-u-me-d that the two caps would pop out at almost the same time. Or maybe it was just that with so much force, once the first one popped out and half the resistance was gone, the other popped as well. Either way, that is what caused me to break the caps. I got them back in the hole, but not straight. They bit into the yoke enough to bind and leave a burr before the joint broke through the cap. But, you're right, with the joint pushing through the cap, I had enough room to get it out, and with the hole (or actually, the entire top of the cap gone) and no joint, it was pretty easy to push the cap back the other way.

 

same thing on mine. it raised a burr so i stopped and cut the u joint off.

you are supposed to press one cap halfway out and grab it with some vise grips or a vise or some channel locks, something that can get a grip and rotate it back and forth to work it out of the yoke then press the other cap out and you'll be home free.
i was using a crap socket and a hammer on mine because i don't have a big vise and my dads arbor press was at his work. hammers aren't as precise as a vise or a press.