Delrin is essentially a type of high strength plastic that is starting to replace some metal components such as door hinge bushings (I may use the words bushing, liner, and sleeve interchangeably) due to its low-friction and high-wear resistant properties. If your door hinges are squeaking, corroded, rusty, or sticking, then you may want to consider this simple upgrade.
The standard cost for a Delrin hinge kit will run $20-30 for a two-door and $40-60 for a four-door vehicle. Try to look for a kit that includes a removal tool, otherwise, the only other tools you will need are a hammer, sandpaper, and something to protect your paint such as tape or cardboard. Other useful tools include a wire brush or a thin, round file for the bore of the hinge knuckles. Installation should take approximately 30 minutes to complete.

The first step is to remove your doors. This includes the nut at the base of the door pins and the limiting strap on the inside of the doors. If you’ve never removed your doors before be careful when you remove your limiting straps as your door could swing wide enough to dent your vehicle. Open the door to approximately 90 degrees and pull the door up to remove it.
Next, clean your door pins, ensure the bushings fit smoothly over the pins, and then grease them.
Because you’ll be swinging a hammer in close proximity to the body of the Jeep I would strongly encourage protecting your paint using cardboard, or a couple of layers of tape. Next, insert the stepped end of the removal tool into the bottom of the hinge knuckle and using a hammer tap the old bushing up and out.
Clean out the inside of the hinge knuckles. I would encourage sandpaper or a wire brush for light buildup and a small, round, fine-tooth file for heavy buildup. Be careful if you use a file not to file away the inside of the hinge knuckle excessively or your new sleeves will fit loosely.
Once the inside of the knuckles bore is clean you can insert the new Delrin bushing by hand. The bushings should become snug around 75% of being fully inserted and if you cannot finish insertion by hand or with the very light use of a hammer then you need to remove the bushing and re-clean the bore of the hinge knuckle. The use of excessive force to seat the bushing can damage it.
The installation of the new door hinge bushings is now complete and you can reattach your doors in the reverse order you removed them.