How to Measure a Flange Yoke Correctly for Replacement
Flange yokes attach a driveshaft to a companion flange, such as on a transfer case or differential. Before measuring, first identify the yoke type. Flange yokes come as male (extended pilot) or female (recessed pilot) designs. A male flange yoke has a raised center piece that goes into the other flange. A female flange yoke has a center hole that the other part fits into. Slip yokes can move back and forth along the shaft. Fixed flange yokes are bolted tight and don’t move.
Steps to Measure a Flange Yoke
1. Identify the yoke type
Check if your driveshaft end is male (sticks out) or female (has a hole). Also note if it is a slip yoke or a fixed flange yoke. This dictates the measurements needed.
2. Measure the bolt circle diameter
Picture a circle drawn through all the bolt holes. You need to find how big this circle is. Get a caliper or ruler ready. Find one bolt hole and measure straight across to the hole on the other side. Go center to center on the holes. Square pattern? Pick opposite holes and measure across. If arranged rectangularly, measure both directions or diagonally to verify.
3. Measure the pilot hole (pilot diameter)
The pilot is the central hole or hub that centers the flange on its mating part. For a male flange, measure how wide the raised center piece is. For a female flange, measure how wide the center hole is.
4. Measure the bolt hole size and pattern
Look at each bolt hole to see if it has threads or is smooth. If it has threads, write down the thread size like M10. If the hole is smooth, measure how wide it is. Also note how the holes are arranged. Also note the hole pattern: square or rectangular.
5. For female flange yokes, measure the U-joint cap and ear width
Female flanges have a recessed area that holds the U-joint caps. Measure the cap diameter and the width between the yoke ears where the U-joint sits.
6. Determine the U-joint series
Take your measurements and figure out which U-joint series you have. Check the distance between the yoke ears too. Then look up that series number in a U-joint book or search online to match it up.
Things to Keep in Mind
First, clean off the flange. Scrape off rust, dirt, and crud from the flange face and pilot hole first. You can’t measure properly with junk in the way. You need good tools. A tape measure works fine for big measurements, but you’ll want calipers for the small stuff to get it right. Check your work. Measure everything twice to make sure you got it right the first time. Look up the specs if you can. Check if you have a service manual or parts book handy. These can save you time. Don’t be afraid to ask someone. When you’re stuck, find a shop that works on driveshafts. They see this stuff every day.
Get the yoke type right and measure carefully. Then you can order the part that actually fits your driveshaft.
About HZSP
Hangzhou Speedway Import & Export Co., Ltd. (HZSP) is a Chinese driveline components supplier specializing in high-quality driveshaft parts. HZSP offers a wide range of industrial and automotive driveshaft products – including flange yokes – built to international standards. With over 25 years in the drive shaft industry, HZSP serves customers in global markets with reliable and precisely manufactured parts. Their product line covers drive shafts, universal joints, CV joints, steering components, and more.