The u joint has four stubs. The pressure applied to each stub puts pressure on a certain point. The u joint usually breaks on a stub and breaks in half. The stub will actually break and then make the whole stub break. The weakest point on the u joint is the c clip holding the dam cap in. Once the c clip spits out the cap moves out causing the ujoint to move. Once that happens it breaks the ujoint and usually the ears on the shaft. Warn has done tests on this and the u joints with greasable zerks dont have the strength of non greasable u joints.

 

I've never really thought of it like that. This changes things. Then again, I never had torque like I do now. ;D <br>So when and if I need joints I should look for solid ones with synthetic grease in them?<br><br>Thanks,<br>Chris

 

<br><br>YES

 

There is an alternative for greasable u-joints - they have the recessed needle zerk on a boss off the center of the cross. I have these in the CV joint on my 78 W200 front shaft (came back from rebuild with them) and on something else, I believe the rear joint on the 78 W200. These have a boss of extra material added to the cross to give enough meat to thread for the fitting. They are a PITA to grease even with a power grease gun but they seem to have very good seals and you do not have to worry about knocking a zerk off. Also solves problem of weakening cap with hole for zerk.

 

Redramnc,<br>The problem with those, if I understand this thread correctly, is that they are hollow in the center of each stub to allow the grease to flow through to the end caps. Being hollow, even if it's a hole drilled in it rather than being cast hollow, more than the hole drilled in the corner for the zirk, weakens them significantly. The sealed joints are solid in the middle.<br><br>Guys, if I misunderstood this, please correct me.<br><br>Chris<br>