A Universal Joint (U-joint) connects the drive shaft with the yokes that will go on either end.  A U-joint moves on three planes, allowing the drive shaft to smoothly absorb any changes in angles that may occur when the vehicle is moving. 

We carry over a hundred different styles and sizes of Universal Joints, from U-joints for semi-trucks to U-joints for agricultural equipment and power take-off systems.  However, for our custom built drive shafts and front drive shafts, we stick to five different styles because they are by far the most common on consumer vehicles.  If you are looking for a specialty U-joint or something less common, please stop by or contact us: info@drivelineofpgh.com.  Likely, we'll be able to help.

When finding the U-joints you need for a front drive shaft or a custom built drive shaft, there are three things you need to determine.


Step 1: Does your U-Joint take inside or outside snap rings?

Step 2: What is the cap diameter of the U-joint?

Step 3: What is the breadth of the U-joint?

ujointmeasurement.jpg
 
 

U-Joint #

1310

1330

1350

1410

3R

 

Snap Rings

Outside

Outside

Outside

Outside

Inside

Cap Diameter

1.063 in

1.063 in

1.188 in

1.188 in

1.125 in

Breadth*

3.219 in

3.622 in

3.622 in

4.187 in

2.556 in**

* If measuring on the yoke, for yokes that have outside snap ring grooves, measure from the inside of the snap ring groove on one ear to the inside of the snap ring groove on the other ear.

** Breadth/Lock Up Yoke measurement for the 3R joint is based on where the snap rings clip onto the joint.  If measuring on yoke, measure from the machined (flat) inside face of one ear to the machined inside face of the other ear.  This is where the snap rings will sit.  Note: If there are no snap ring grooves on the yoke, that means it takes inside snap rings.

Inside or Outside Snap Rings?

Snap rings are a small piece of metal that keeps the U-joint from sliding around within the yoke.  Inside Snap rings fit flush against the inside of each ear on the yoke.  A yoke which takes a joint that needs inside snap rings will have a machined (flat) surface on the inside of the ear.  Outside snap rings sit in a groove cut towards the outside of the hole in each ear of the yoke.  See the pictures below.

Inside Snap Rings

Slip Yoke for Inside Snap Rings

Slip Yoke for Inside Snap Rings

U-Joint with inside snap rings

U-Joint with inside snap rings

Outside Snap Rings

Slip Yoke for Outside Snap Rings

Slip Yoke for Outside Snap Rings

U-Joint with Outside Snap Rings

U-Joint with Outside Snap Rings

Determining Inside or Outside Snap Rings on a Pinion Yoke

The pinion yoke, the yoke from the rear differential where your rear U-joint will sit if not using a flange, will either have tabs in the ears or not.  If it has tabs, it takes a U-joint with outside snap rings.  The tabs take the place of the snap rings to prevent the U-joint from sliding because the ears are halved and can't take a full snap ring.  If the pinion yoke doesn't have tabs, the inside of the ears will be machined (flat) and will take a U-joint with inside snap rings.

Pinion yoke with tabs (Outside Snap Rings)

Pinion yoke with tabs (Outside Snap Rings)

Pinion yoke without tabs (Inside Snap Rings)

Pinion yoke without tabs (Inside Snap Rings)

Cap Diameter

The cap diameter is simply the measurement across the outside (the circular part) of the cap.  When measuring on a yoke to determine what U-joint it takes, just measure the hole in the ear of the yoke which will hold the cap.

Cap Diameter

Cap Diameter

 
 

Breadth/Lock Up Yoke

The breadth measurement is based on where the snap rings sit.  It is the measurement from where one snap ring sits across the U-joint to where the opposite snap ring sits.  If measuring on the yoke for a U-joint that takes inside snap rings, measure from the inside, flat surface of one ear to the inside flat surface of the other ear.  If measuring on the yoke for a U-joint that takes outside snap rings, measure from the snap ring groove in one ear to the snap ring groove in the other ear.  If measuring a U-joint that takes outside snap rings, simply measure from the outside of one cap to the outside of the opposite cap.

Breadth measurement for joint that takes inside snap rings

Breadth measurement for joint that takes inside snap rings

Breadth measurement for joint that takes outside snap rings

Breadth measurement for joint that takes outside snap rings

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