Monday, March 21, 2016

u joints...

the grease fitting throws them off balance, and can cause them to leak, and the lack of metal in the grease channel makes them weaker... but I've also been told to make sure the zerk fitting is in between the driveshaft yoke and the diff yoke, so it's in the crush zone

the u joint without the fitting is naturally balanced

1 comment:

  1. 1) I can't believe that anything with so little mass (zerk fitting) and so close to the center of the axis of rotation could possibly affect the balance of the much, much heavier drive shaft enough to cause any noticeable vibration.

    2) Sever duty vehicles like race cars and pulling trucks should use u-joints without a zerk. U-joints in these applications will probably be replaced by routine service before they would ever run out of lube.

    Any normal duty vehicle (passenger car, pickup truck) should use a u-joint with a zerk. In these applications,failure due to lack of lube is much more common than failure due to breakage.

    3) The only thing I worry about as far as zerk location on a u-joint is concerned, is to locate it in such a manner so a grease gun fitting can fit on to it. If you put in the wrong way, a grease gun fitting will not fit between the yolk and u-joint, particularly if is a large angle between the drive shaft and pinion gear and/or transmission output. Once you put a u-joint in the wrong way, you are probably not going to go through the hassle of removing it, turning it around, and reinstalling it. This is another good argument for using u-joints with no zerk fitting.