Air Lift Air Bag and Compressor Install
This is my first post on TT as well as my first mod. Being a new member, I thought I would start off with a DIY. I posted this install on another forum but wanted to share it here as well. Enjoy!
I have a 2010 CM 5.7L 4x4 with factory tow package. The choice for air bags came down to either Firestone or Air Lift. Both kits are "no drill" installations and both increase "level load" capacity by 5000lbs. I went with Air Lift since AutoAnything was running a year-end 15% discount plus free shipping. In addition, Air Lift is offering a $100 factory rebate (ends 1/31/2012) when you combine the purchase of air bags (#57299) with any on-board compressor system (I chose #72000). Anyway, the incentive was too much to pass up so I ended up buying both.
Even though this is a "no drill" installation, you do need to cut the jounce bumper for clearance between the lower bracket and leaf spring. I’ve read on TT and other forums that some members simply remove the jounce bumper but on page 7 of the installation guide it states, "The jounce bumper has been cut to support the lower bracket. It will be necessary to draw the lower bracket into the jounce bumper using the u-bolts. This is an intentional way to mount the lower bracket." Not wanting to destroy a perfectly good part, I did a quick product search at McMaster-Carr and found a 1-1/4 x 1-1/4 x 12” length of neoprene rubber with a durometer rating of 75A (part# 1457T43)…about the same hardness as the soles on a pair of boots. I cut this into 2” sections, which is the width of the leaf springs. After removing the jounce bumper I noticed there was a bolt/nut hidden under the jounce assembly. I used my Bridgeport and a 3/4” end mill to create a blind hole in the center of my rubber block. Perfect fit!
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After assembling the upper and lower brackets, roll plate and 90* swivel air fitting, it was time to set the assembly onto the leaf spring. I used a pair of zip-ties to compress and hold the assembly during this placement. Even with all the air compressed out of the right-side bag, I was unable to fit the assembly in place due to insufficient clearance between the 90* air fitting and upper jounce bracket. I removed the air fitting and reattached it once the install was complete. It was not easy getting a wrench inside the frame to tighten this fitting but it can be done. The left-side bag went in as a complete assembly so maybe there was less load on that side…I don’t know but either way it was a tight fit. (Note: if you use the zip-tie technique, do not cut the ties until you have loosely mounted the upper bracket to the jounce bracket. The 90* swivel air fitting is fragile and you want to make sure it is lined up with the existing hole in the frame before releasing tension on the bags). Last thing to do is trim off the excess all-thread on the u-bolts.
Now that the bags are installed, it was time to mount the compressor. A lot of people install their compressor units inside the engine compartment but Air Lift recommends against using this location. I removed the spare tire and found a dry, well protected area along a cross member between the frame. I used a 90* electric drill with 6” drill bits to create the four mounting holes. It was a PITA to drill but I was very happy with the results. I installed the manifold on the frame just behind the left air bag next to the existing Toyota Fuel Controller. The wiring harness for the compressor was just long enough to reach the manifold, which needs to be less than 24”. The relay (attached to the wiring harness) was grounded to the mounting bolt behind the compressor along with two other grounding wires.
The last step was to install the pneumatic lines and run power to the compressor system. I didn’t believe the push-to-connect fittings would work but to my surprise they seem to do the job and were easy-peasy to install. Only had one leak which required re-seating the tubing into the fitting and it was fixed.
The instruction guide calls for running the positive lead of the wiring harness to the fuse box. Since I have the tow package I knew there was a +12V power source somewhere under the truck. I located the trailer battery charging line and used a butt splice to make the connection. Make sure you check which wire has power before tapping into it (turn key ignition to ACC).
The leader hose that comes pre-connected is “Air Out” and goes to the manifold. With the compressor mounted so high up and protected by the spare tire, I simply screwed my filter directly into the body of the pump, eliminating any extra fittings and tubing. This will also make for easy filter changes in the future.
Here's a pic of the mounting bolts for the manifold (seen from the outside) as well as the manual fill schrader air valve (black cap).
As a final note, the Air Lift instruction guide is a joke. The hole-pattern templates were completely wrong for both the compressor and manifold. I used a center punch to mark my holes before drilling. That said, it is an awesome system. Finally, if you remove the jounce bumper, the factory torque spec for the rear spring u-bolt is 74 ft-lb and should be tighten in a crisscross pattern. If you have aluminum wheels, the torque spec is 97 ft-lb.