WFO Concepts - U-Joints

U-Joints are categorized by their method of retention (inside or outside snap rings) and their physical dimensions.  You will need a caliper and a relatively undamaged u-joint.  First measure the bearing cap.  If you have two different cap sizes, measure the largest one.  Second measure the distance between the retainers.  If the retainers are outside the caps, measure from end to end.  If the retainers are on on the cap, measure from the outside of one retainer groove to the outside of the other retainer groove.  Now cross reference those dimensions with the ones below, and find out what u-joint you need!

How to determine what u-joint you have:

1210 Series u-joint - Cap diameter 1.0625" - Cap to cap 2.4375"
1310 Series u-joint - Cap diameter 1.0625" - Cap to cap 3.2188"
1310 Series large cap - Cap diameter 1.125" - Cap to cap 3.2188"
1330 Series u-joint - Cap diameter 1.0625" - Cap to cap 3.625"
1330 Series large cap - Cap diameter 1.125" - Cap to cap 3.625"
1350 Series u-joint - Cap diameter 1.188" - Cap to cap 3.625"
1410 Series u-joint - Cap diameter 1.188" - Cap to cap 4.188"
3R Series u-joint - Cap diameter 1.125" - Clip to clip 2.5625"
7260 Series u-joint - Cap diameter 1.078" - Clip to clip 2.125"
7290 Series u joint - Cap diameter 1.125" - Clip to clip 2.625"