What are ford, green or purple keys and key indexing?
Well we already discussed what a key is and how it works. Now lets talk about the indexing of keys. The key has a hex shaped hole in it that the torsion bar goes on. How this hole is indexed or clocked effects how much you can turn the adjusting bolt before the key bottoms out on the top of the cross member or you run out of bolt. The different kind of keys are indexed different, which allows some to make some bars be adjusted further. To make things even more complicated the hex heads on the bars don’t line up with one another, and some bars are different. But as a general rule, all bars you will find on a half ton truck are about the same and all bars on an HD truck are about the same. The half ton trucks have the “green” keys in them and the HD trucks the “purple” keys in them. We call them green and purple because when the keys are new they have a green or purple mark on them. After about 2 weeks in the real world you cant see this anymore though because it will be a big brown rusted key! The only way to tell them apart then is to determine what truck it came off of or compare it with a known key. Now where do Ford keys come into play? Ironically ford uses the same torsion bar design with the EXCAT same hex head. The keys are exactly the same dimensions except the indexing is different. A ford key is indexed more than either the green or purple keys. This means when you put it in a GM truck it allows the torsion bars to be cranked further up. This works on both half ton and HD trucks BUT since the purple key is the least indexed you will never be able to get the Ford key to load in a HD truck, its just too indexed. If you did get it to load your CV, tie rod and ball joint angles would be so bad it wouldn’t be drivable. Don’t worry though your not left out if you have an HD. He green keys will work for you! They are indexed in the middle, less than ford keys but more than purple, so they work the same way as the Ford keys do on the half tons. Now if you put purple keys into a half ton truck you would not be able to crank as far as you originally would have because they are indexed less. Ford keys are easy to identify because of the extra hole in them.
