How to Install a Rear Over-Inflate

Get that extra ground clearance in that long and low truck when you need it!

This is a pretty simple modification to make and can be done with minimal parts. You’ll need a ½” electric over air solenoid, a momentary toggle switch of some sort, a good supply of ½” airline and a few brass fittings. If you want the switch to match the rest of the switches in your truck, a cruise switch will work just fine. The amount of airline and type of fittings may change depending on your exact application, but they are both relatively easy items to find at your local hardware store.

4 State Part #09-051403: Electric Air Solenoid (photo)
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4 State Part #29-0510010: Over-inflate Complete Kit

STEP 1

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Drain the truck’s air supply and locate the ½” airline going into your air bags. There should be a ½” airline that runs from your front bag to your rear bag on each side of the truck. This is the line you will use. Cut this line on each side and put in a “T” fitting (photo #1).

STEP 2

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Both of these lines will go to a 3rd “T” fitting. This fitting will go to the outlet side of your solenoid wherever you choose to mount it. With some solenoids, it makes no difference which side is the inlet and which is the outlet. If it matters with the solenoid you are using, it should specify on each side. In this case, we made a simple bracket and bolted it to the leveling valve bracket at the back of the truck for easy access (photos 2A and 2B).

STEP 3

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The other side of your solenoid, or the “inlet” side, will need to be tapped into a good air supply. Your air tank should have a few spare fittings that are just plugged off. You can simply remove one of the plugs and connect your ½” airline directly to the tank (photo 3A).

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This diagram shows how and where the connections of this system should be made (photo 3B).

STEP 4

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If you have a spare switch on your dash, you can use it. If not, you will have to add one – but remember, your best option will be a momentary switch. You will want to find a fuse-protected “ignition on” power source. You can tap into this power and run it to one side of your switch. The other side (or “switched side”), will go to your solenoid. On a lot of solenoids, it doesn’t matter which is power and which is ground, especially if the wires are the same color. On this solenoid, blue will be the power wire you connect to your new “switched” power (photo 4A).

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On this example, the yellow wire (covered with black plastic loom) just needs to be hooked to a chassis ground (photo 4B).

STEP 5

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Now, start the truck up, let it build some air and try your switch. The truck should immediately over-inflate the rear bags and gain you a few inches of additional ground clearance. When you let go of the switch, the leveling valve will let air out of the bags until the truck is back down to normal ride height. No more worrying about dragging your tanks or long-drop rear fenders on that pesky speed bump or those rough spots in the yard or on the road – or even out in a field doing a photo shoot (photo 5)!

To find more great stuff for your big rig (or maybe a gift for someone else’s), visit www.4statetrucks.com today. 4 State Trucks is the proud home of Bryan Martin and the Chrome Shop Mafia!

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