AIR SUSPENSION SYSTEMS
This is a pic of everything that comes with the kit.
Place floor jacks underneath the frame rails just in front of the lower control arms, remove your wheels and place them in front of your jack stands.
Spring compressors can be really helpful to remove your springs especially if they are taller than stock.
Cut out and use the centering guide provided with the kit to find where you will need to mark your drilling point. Use a dab of grease to hold the guide in place and be sure to use a center punch.
Be sure to use a Cobalt or Titanium tip drill bit when drilling through your spring perch.
Using a Dremel with a grinding point, clean up any rough edges or burrs.
Shove the deflated air bag through the coils.
Re-inflate the air bag once inside the spring.
Re-install your spring with the air bag in it.
Feed the air hose through the bottom of the spring perch and then attach it to the air bag nipple using one of the hose clamps included with the kit.
Here's a view from underneath my driverside spring perch.
Here you can see how I routed the air hose from the passenger side of the axle.
Here you can see how the driver side and passenger side air hose is connected by a "T" that follows the axle vent hose up to the tub.
Here's a diagram from Air Lift's instructions showing how you need to assemble your inflation valve.
Because I have a 1" body lift, I was able to drill a small hole in the lip of the tub underneath the tailgate. I then used this hole to attach the inflation valve.
Here is a side view of the inflation valve going through the body lip.
Here's what my coils look like when all is said and done.
This is what the Air Lift bag looks like compressed. As you can see, it acts very much like an extended bumpstop preventing over compression of the coil.
This is what it looks like at a droop.
Here is a close up of the drooped side so you can see how much space is in between the bumpstop and Air Lift bag.
The Air Lift bags keep my rear end from sagging and work perfectly on the trail.
Jeep TJ Air Lift Suspension

After installing my used 3" coils, I noticed that the rear end of my Jeep sagged quite a bit with the added weight of my hard top, Kilby gas tank skid and roof rack. Once I loaded up with gear and family, I could pretty much kiss my lift goodbye. To top it off, I'm currently in the market for a swing-away tire carrier/bumper and can't imagine how that's gonna help things out. What to do right? Well, my first thought was to get a set of new 4" coils for the rear to compensate for all the extra weight but in the end, I was afraid that they too would just not be enough. So, I did some research, talked to a few people and decided that maybe what I needed was an Air Lift Suspension.

Unfortunately, I have never seen this done on a TJ before but couldn't see any reason why it wouldn't work. My local 4WheelParts shop told me that a company call Air Lift no doubt makes a kit for TJ's and that they sell for only $79. Because I technically have a 4" lift (3" coils/1"spacers), I decided to contact Air Lift directly to make sure they sold a kit that would fit my needs. Well, the guys there were very helpful and they told me that the kit I needed has air bags that measured 5.38" wide X 6.50" tall. I just needed to make sure that the inside diameter of my aftermarket coils were at least 5.38" wide. Any less and the bags would be at risk of damage and/or pre-mature failure. This was not a problem for me so I went ahead and bought the kit.

Although Air Lift sells kits that come with neat air compressors and onboard controls, I decided to save my cash and just get the basic kit with the standard valve stem you can fill up with any tire pump.

This is not a difficult mod but it is time consuming. I would allow for about 3 hours from start to finish.

What You Will Need
Air Lift 1000 - Part#60734 (5.38"wide X 6.50" tall)*
• Metric (13,15,17,18,19mm & 3/4") Socket & Wrench Set
• Ratchet
• Torque Wrench
• Ratchet Extension
• Hand Drill
• 1/2" & 5/16" Metal Drilling Bit
• Dremel w/Grinding Bit
• Pliers
• Safety Glasses
• Floor Jack
• Jack Stands (2 minimum)
• Wheel Chocks
• Spring Compressors
• Center Punch
• Hammer
• White Lithium Grease
• Zip Ties
• Air Pump
• Tire Pressure Regulator

* Part# may be different for your application. Please consult the vendor you are purchasing your kit from or contact AirLift directly to verify what you need.

Installation
1. Park on level ground, chock your front wheels, crack loose the lug nuts on your rear wheels and jack up the rear end of your Jeep from the differential.

2. Place floor jacks underneath the frame rails just in front of the lower control arms, remove your wheels and place them in front of your jack stands. Lower the jack until your Jeep is resting on the jack stands but leave the jack under your differential for now.


3.
Remove your rear shocks, disconnect your rear swaybar links and unbolt your rear track bar at the frame. It may help to lower or raise your axle a bit to make the removal of your swaybar links and trackbar. If you're axle is at the correct height, the removal of these parts should be quite easy.

4. Now, lower your jack completely down slowly making sure too much strain is not be placed on your brake lines.

5. Place your jack underneath the passenger side of the axle and raise it so that your spring is compressed. Then attach your coil compressors to the coil and make sure they are on snug and that the safety pins are engaged. Springs are very dangerous to handle when compressed so be sure to wear safety glasses during this procedure.

6. Slowly lower your axle back down to the ground. Your spring should just about fall out at this point but if it doesn't, you can encourage it out by pushing down on the axle with your foot while pulling. If that still doesn't free it, crank down each compressor a bit using a 3/4" wrench until it does. Make sure you crank each compressor down evenly.

7. Carefully set your coil down, clean your spring perch off of dirt and if you have a bumpstop extension from a previous lift, you will need to remove it at this time and return your bumpstop to it's factory height. Measure the distance between the bottom of your bumpstop and the spring perch. It should be somewhere close to 6" if you have a 3.5"-4" coil lift. If it is not, you may have to trim off some of your bumpstop with a hacksaw.

8. Cut out the circle template provided with the kit, smear a dab of grease on the bottom of it and then place it on the center of your spring perch. Now, tap the center of the template with a center punch and then remove the template.

9. Drill a hole through the center of your spring perch using a 1/2" cobalt or titanium drill bit. The instructions call for a 3/4" drill bit but the largest metal drilling bit I could find was 1/2". Fortunately, the diameter of the air bag hose is only about 5/16" and 1/2" seemed to be more than adequate.

10. Using a Dremel with a grinding bit, clean up all the edges of any sharp metal or burrs around the hole you just drilled. Be sure to clean the bottom side of the hole underneath the spring perch too.

11. Grab an air bag, pull the black plug off the inflation nipple, deflate it as much as you can and then put the plug back on. Take notice which way is up on your spring and then shove the deflated air bag through the coils as shown in the pic to the right. Make sure the inflation nipple is pointing towards the bottom of the spring. Once in far enough, pull the black plug off, let the air bag re-inflate and then center it within the spring.

12. Carefully re-install your spring making sure the inflation nipple is still pointing down.

13. Using a pair of pliers, attach a hose clamp on to the end of the air hose provided with the kit and then feed it through the hole you drilled in the spring perch from the bottom up. Do not cut the air hose for any reason at this time.

14. Connect the air hose to the inflation nipple on the air bag and then secure it by sliding the hose clamp up over it. Take the remaining hose and route it down around your axle and through your shock mount as shown in the pic to the left. Take some zip ties and attach the air hose to your brake line and follow it over to the driver side and let it hang there for now.

15. Slowly raise your axle back up and compress the coil enough that the spring compressors loosen their grip. Use a 3/4" wrench to make whatever adjustments you need to loosen up the compressors enough to be removed.

16. Remove the spring compressors and carefully lower your axle back down.

17. Repeat steps 5-12

18. Using the hose that you routed over earlier, feed it up, around your axle and through the shock mount as shown in pic to the left. Now, slip a clamp on the end, feed it through the hole in the spring perch and then attach it to your air bag like before. Both bags should now be connected by the same hose.

19. As in step 14, take a couple of zip ties and attach the air hose to your brake line until you reach axle breather hose. Cut the air hose at this point to remove the excess and then re-connect the two hose ends using the "T" fitting and clamps provided with the kit.*

* note: The kit actually comes with a second schrader valve so that you can set things up in a way that will allow you to inflate each bag separately. I choose not to go this route because I felt that it would be beneficial to have both bags share the same air presure. This would allow one bag to deflate it's air into the other bag as my axle articulates on the trail allowing for maximum stuff.

20. Take the excess hose, slip a clamp on one end and then attach it to the top of the "T" fitting. Using zip ties, follow and attach the air hose along the axle breather hose. Just let the hose hang out the back for now.

19. Repeat step 15-16

20. Okay, at this point go ahead and re-attach your track bar (making sure to torque it to 85 ft. lbs.), sway bar links and shocks. Again, raise or lower your axle until the bolts to each of these parts connect easily.

21. Re-attach your wheels and tighten your lug nuts but do not torque them at this time. Remove the jack stands from under your Jeep.

22. Lower your Jeep and torque your lug nuts to 95 ft. lbs.

23. With your Jeep safely back on the ground, we will now address where to locate your air hose inflation valve. Because I have a 1" body lift, my Jeep has a lip that hangs down in between the tub and rear cross member. Towards the driverside of the Jeep, there should be enough space behind this lip and the gas tank that you can mount the inflation valve here. Start by locating your drilling point and marking it with a center punch.

24. Carefully drill a 5/16" hole using a cobalt or titanium drill bit. Again, be very careful not to punch right through as your gas tank is sitting just behind the lip and you don't want to be poking a hole in it. Clean the edges of the hole using your Dremel and grinding bit. I also went ahead and touched up the edges with some touch up paint to prevent corrosion.

25. Slip on a clamp to the end of the air hose, attach the valve, and secure it with the clamp. Thread one of the valve nuts on to the very back and follow it with a spoked washer. Then, carefully slide it through the hole you drilled and fasten it using a rubber washer, regular washer and nut as show in the diagram to the left.

26. Slowly inflate the air bags using a standard tire pump to 35 psi (DO NOT exceed 35psi) and then check for leaks along all the connection points using soapy water.

27. Deflate your air bags in 5psi intervals and take your Jeep for a spin between each one to determine what gives you the best ride. DO NOT let your air bags fall below 5psi at anytime. I usually keep mine at about 10psi.

28. Recheck the air Pressure in the air bags 24 hours later. A 2-4 psi drop is normal after installation but if you see more than a 5psi drop, repeat step 26.

Maintenance
To operate your Air Lift suspension, simply inflate the air bags to 35psi before you load up your Jeep. Then, deflate them until you have achieved a desired height or comfort in ride.

Operation
Unless you installed one of the more expensive Air Lift kits that come with a self regulating compressor that always maintains a constant psi, it is important to check the pressure of your air bags on a regular basis to make sure it doesn't fall below 5psi. As is indicated in the instructions provided by Air Lift, I have been checking mine once a week. I just takes a few seconds to do and so far, I have not seen any significant loss in pressure. I will keep you updated on this.

Post Installation Notes

Initally, I was a bit concerned about how these air bags would effect my axle articulation. However, after doing some initial testing, I have found that the bags compress quite nicely and do a great job of acting as bumpstops. So far as I can tell, I have not lost any stuff and the bags just fall with my coils on the droop side. I will try to take some pics of flex as soon as I can and post some pics.

Update 11/15/03
I have taken my Jeep out on two easy wheeling/camping trips with my family and can tell you that these air bags performed perfectly. Loaded up with close to 200 lbs. of gear + passengers and a dog, I was still able to keep my Jeep from sagging. On the trail, I didn't even notice they were there. Needless to say, I am super happy with my decision to go this route. Oh, one thing to remember is to deflate your air bags once you're back in town and unloaded. I forgot to and the rear of my Jeep sat at about 5" taller than stock causing some serious drive line vibes. After airing them down to about 15 psi, all was back to normal. :)

That should be it. Please let me know if you have any questions.
Project-JK.com - Jeep JK Wrangler Website





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