This has been proven on the 88-06 1/2 Silverados (ford keys), and the 99 1500HD, 2500, and 2500HD, and it will work for a 3500 as well. DO NOT SEND ME A PM UNLESS U READ THIS WHOLE THING, IM TIRED OF GETTING PMS WHERE PEOPLE WERE TOO LAZY TO READ THIS.
***WARNING*** This procedure can be dangerous if not properly done. If using a 3/4 Truck, or 1 ton bars, I HIGHLY recommend using a GM torsion bar puller over the one shown here. The Staff, and Partners of Fullsizechevy.com are not responsible for your mistakes, and/or injuries that may occur while performing this procedure. Do not use the smaller version on the puller I use (5-ton) that thing has broken on a member here!!! Play at your own risk!!! ***WARNING***
**This thread is kind of big (pictures), so i am sorry to all you guys not using broadband.
****HIGH RESOLUTION PICTURES***
Okay, many of you guys have asked these questions at 1 time or another. So I figured I would help you members out. This is a tech article telling (showing) you how to crank, and/or replace torsion bars, as well as installing ford keys, and what they are. If you have questions, start asking, but don’t ask until you read this entire post to prevent double questions. On with the show....
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For more reader friendly instructions, I color coded this as follows:
Torsion Bar replacement
Ford Key Install
Torsion Bar Cranking
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When I actually took these pictures I was doing a ford key install, they are use the same information, and same tools.
First of all, the all mighty torsion bar list:
CHEVY TORSION BAR CODES AND RATINGS:
15048307-LH (code XK) (Max torque 4553)
15048308-RH (code XK) (Max torque 4553)
15048309-LH (code XL) (Max torque 4626)
15048310-RH (code XL) (Max torque 4626)
15712407-LH (code WX) (Max torque 4863)
15712408-RH (code WX) (Max torque 4863)
15048311-LH (code XM) (Max torque 5638)
15048312-RH (code XM) (Max torque 5638)
15058267-LH (code YH) (Max torque 5913)
15058268-RH (code YH) (Max torque 5913)
15712409-LH (code WY) (Max torque 5913)
15712410-RH (code WY) (Max torque 5913)
15528957-LH (code GG) (Max torque 6709)
15528958-RH (code GG) (Max torque 6709)
15712411-LH (code WZ) (Max torque 7267)
15712412-RH (code WZ) (Max torque 7267)
15528963-LH (code GK) (Max torque 8615)
15528964-RH (code GK) (Max torque 8615)
15528965-LH (code GL) (Max torque 8782)
15528966-RH (code GL) (Max torque 8782)
15732338-LH (code XG) (Max torque 9054)
15732339-RH (code XG) (Max torque 9054)
15528959-LH (code GH) (Max torque 7161)
15528960-RH (code GH) (Max torque 7161)
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Here is the Ford key part number:
*The parts are universal, u dont need one for the left and right... they are both the same.
XL3Z5B328CA
A good place to get them is Ford Parts Online
**These keys work best on 1/2 tons
For the 3/4 ton trucks and above use the "green key" or the 1/2 Chevy key. 15592573 you can get them from GM Parts Direct
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TOOLS:
Floor Jack:
7-ton Craftsman Puller:
18mm/20mm sockets, and a ratchet
On with the install
First of all I recommend using at least a 3-ton floor jack, and some wood for jacking the front end up. Jacking the front end off the ground, and letting the tires lift off the ground takes a lot of the stress off the torsion bars. This makes your job safer, and easier. At this time, you may want to throw some jack stands under it, I didn't because im stupid. It is somthing I recommend to someone doing this though.
Now that your tires are not touching the ground, you can begin to unload your torsion bars! For those of you not familiar with the location of where to do this, here is the picture of the cross member:
I circled the adjusting bolts.
If you just want to crank your bars, then tighten these bolts with the 18mm socket, and try to drive it around every few turns. Or drop it down and up again with the jack, this helps it settle. You are done cranking your bars. Easy Huh? If your height changed more than a inch, go get it aligned
Unloading the bars is a fairly simple procedure, the way I find to be easiest is to loosen the bolts until about a good inch is sticking out. Then place the puller on.
The red circle is where a dimple is on the key, this is where u install the puller.
(quadcab's picture)
After you hand tighten this tool into the dimple, use your 18mm socket, and loosen the bolt.
Avoid using your hands under the cross member, just in case the puller slips, and takes your hand off. Once you get the bolt out, now you must remove the thing that held the bolt in.
Again, don’t use your hands for this 
Use your ratchet end and push it out through the other side
Just FYI all the stress is now on the puller. I used a 20mm socket on the puller, it isn't a exact fit, but it works
Start to loosen the puller bolt with your ratchet, until the puller becomes loose, as this point, you have unloaded a torsion bar, congrats!
Now to remove the keys, you simply grab it like this:
and shake the bar back and forth, if you have never done this, those bars are going to probably be harder to remove, try using a hammer to bang the bar around, and WD-40 never hurt
Once the key falls, push your torsion bar out of the cross member.
For changing out the bars, at this point, you completely remove the current bars, and load in your new ones, I recommend that the sticker end of the bar goes towards the back (as they came off) and make sure u pay attention to the L and R which indicate which side they should be installed on. After taking that into consideration. Just simply put your new bars in, slide them back through the cross member. Hold the key up so that it slides back in. (see pic below) There is really only 1 way to install that key, so don’t think your going to mess it up. Try to think back on how it came out how if your not sure how to reload the bars, read down as I will get to it in the key installation
at this point, if u compare the 2 keys like so:
You will see that at the same position, the ford key's bolt dimple is lower, thus twisting the bar more with less cranking
Now just simply slide your new ford key into the cross member, and slide the torsion bar through it, this key will only install 1 way, so don’t think you are going to mess it up:
Now if u look straight up through the cross member, try to center the key before continuing. To make noise a tad better, spray a small amount of WD40 or something similar in the loading/unloading dimple. (this isn’t necessary, I just had some noise from the metal twisting against each other from the puller, and it made a scary noise 
) Now place to puller back on the cross member, and hand tighten. Now using the ratchet, and 20mm socket, tighten the bolt on the puller:
Once you tighten it past the hole u removed the "bolt holder" from try placing it in there with pliers:
It is okay if it doesn’t fit all the way yet, if it doesn't leave it kind of sitting there, this is kind of emergency back-up incase the puller breaks. Keep on tightening until it fits all the way through Again, avoid using those hands at this point insert the bolt, and using your 18mm socket, secure it against the key's adjusting bolt dimple. Now take off the puller. using the 20mm socket.
You are now finished!!! Let your rig down, and take it for a test drive, it may drop a little after the test drive. If it does, then jack it back up, and tighten the adjusting bolts a few more turns, to get the look u prefer. Just know the more u crank, the more angle you will have, and the more chance you are going to have of breaking something
***ALIGNMENT IS REQUIRED***
This was my finished product:
