Mechanics Universal Joints and Yokes

Mechanics or “wing style” driveshaft parts have been used in driveshaft applications since the early 20th century. So named for their ease of replacement, Mechanics joints and yokes come in a variety of sizes and torque ratings to cover mobile and stationary powertrains. Though their use in new applications has declined over the years, wing bearing parts are still in the field around the world. Many wing style end yokes have been discontinued and may be difficult to find. Here at Randy’s we have a better inventory than most in wing style components and have sources for those we don’t have on the shelf – we can still repair most of the wing bearing style shafts that come to our doors!
 Above left is a wing style joint with four threaded bearing caps and on the right is one with four drilled caps. Joints are also available with combinations of the two: two drilled and two threaded on the same joint. A threaded cap will require a drilled hole yoke – the bolt comes through the back of the yoke ear and is threaded into the joint cap. A drilled cap requires a threaded yoke hole – the bolt drops through the bearing cap and is threaded into the yoke. When specifying a wing style joint the cap combination must be noted as well as the series.

Though there are many other measurements that could be noted on a wing style joint, the pilot diameter is the telling one. The pilot diameter is measured on the yoke side of the joint caps, edge to edge. It is the machined diameter that centers the joint on the yoke, and the yoke has a matching pilot (see photo at left). Wing style yokes come in threaded hole and drilled hole so it is important to specify this detail in addition to other required measurements when searching for a Mechanics yoke. The yoke shown is a drilled hole and requires a threaded hole bearing cap as above, left.

Mechanics Joint ID Chart

Mechanics style parts are sized by series designations that end in the letter “C”, 2C, 3C, 4C, etc. The most popular sizes still seen today are listed below but we do have inventory on-hand in all series. We stock Mechanics style joints and parts manufactured by Meritor, though there are other makers. Most of the smaller series (series 5C and under) are made by Rockford Powertrain and we do stock down to 2C parts. If you have a wing style joint or part smaller than what is listed pleased call us – we do have them! There are larger series than listed here as well, up to series 15C, that we stock as well. Also, Twin Disc manufactures wing bearing components, such as J490, that are dimensionally very close to some Mechanics series. Please call if you think you might have a Twin Disc series.

Please Note: In the part numbers below, HWD (high wing drilled) is a joint with all four bearing caps drilled; DWT (delta wing threaded) is four threaded caps; HB (hybrid) indicates two drilled caps and two threaded caps. There are more possibilities, usually in the smaller joint series – please call if you have questions!