How to Install a Sprinter Van Air Bag Kit

A rear air bag kit is one of the most useful upgrades for a working or camper Sprinter. It lets you level the van under load, and it's a job many owners do themselves. Most installs take 2–3 hours. This guide shows how to install a Sprinter van air bag kit from BOSS, so you know what's involved before you start.

Always follow the installation guide that comes with your kit. It has the exact bracket positions, bolt sizes and torque values for your van. This article is an overview.

Which kit do you have?

We sell three BOSS Sprinter kits:

Each includes two BOSS Extreme Series air bags, four custom brackets (upper and lower), mounting hardware, SAE J844 air line, and two Schrader valves on a stainless steel panel.

Tools and supplies

  • Floor jack and two rated jack stands
  • Wheel chocks
  • Socket set and wrenches (sizes are listed in your kit's instructions)
  • Torque wrench
  • Drill and bits, only if your kit's instructions call for them when mounting the valve panel
  • Sharp tubing cutter, or a utility knife for a clean square cut on the air line
  • Cable ties
  • Soapy water in a spray bottle, for leak checks
  • Safety glasses and gloves

Step 1: Park safely and support the van

Park on flat, solid ground. Chock the front wheels. Raise the rear of the van with a floor jack at a frame lifting point, then support the frame on jack stands. Never work under a van held up only by a jack.

Lifting the frame lets the rear axle hang down a little. That opens the space between the axle and the frame, which makes the bags and brackets easier to fit.

Step 2: Check the space and plan the layout

Before you bolt anything on, hold the brackets in place to see where they'll sit. Look for brake lines, wiring, the exhaust and the park brake cable nearby. Plan to keep the air line well away from the exhaust and any moving parts.

Step 3: Assemble the bags and brackets

Attach the upper and lower brackets to each air bag, following the orientation shown in your instructions. Hand-tighten for now, so you can adjust the fit.

Step 4: Mount the assembly

Position each bag assembly between the axle and frame. Fit the lower bracket to the axle and the upper bracket to the frame, using the hardware supplied. Check that the bag sits straight up and down, not leaning or twisted. Then tighten every bolt to the torque values printed in your kit's instructions.

Repeat on the other side.

Step 5: Route the air line

Mount the stainless Schrader valve panel somewhere easy to reach, such as behind the license plate or under the rear bumper; your kit's instructions show the recommended spot for your van. Then run an air line from each bag to its valve:

  • Cut the line square with a sharp cutter. A ragged cut can leak.
  • Keep the line at least a few inches from the exhaust.
  • Avoid sharp edges, and anything that moves as the suspension travels.
  • Leave a gentle loop near each bag, so the line can flex as the axle moves.
  • Secure it every foot or so with cable ties.

Push each line fully into its fitting.

Step 6: Inflate and check for leaks

With the van still on stands, add a small amount of air to each bag, using the test pressure given in your kit's instructions. Spray soapy water on every fitting and valve. Bubbles mean a leak: push the line in further or re-cut it, and test again.

Step 7: Lower the van and set the pressure

Remove the stands and lower the van. With your usual load on board, add air in small steps, measuring the rear ride height, until the van sits level. Most BOSS kits list a working range in psi on the product page. Stay inside it.

Step 8: Check again after a short drive

Drive for a few miles, then recheck the pressure and look over the fittings and line routing. Recheck after your first long trip too.

Common mistakes to avoid

  • Ordering the wrong axle kit. The 3″ and 4″ axle kits aren't interchangeable. Confirm your axle before you start.
  • Routing the air line too close to the exhaust. Heat softens the line and causes leaks.
  • Leaving a bag twisted or leaning. It should sit straight between its brackets.
  • Skipping the leak check. A slow leak is much easier to fix with the van on stands than on the road.
  • Over-inflating. More air than you need gives a harsh ride and puts extra load on the brackets. Stay inside the kit's listed range.

Tips for living with air bags

  • Keep at least 5 psi in them when empty, so the bags keep their shape.
  • Adjust for each load. More weight needs more air, and less weight needs less.
  • Add on-board air if you adjust often. A BOSS compressor or a complete air bag compressor kit lets you set pressure without a gas station air line.
  • Inspect the bags when you rotate tires. Look for chafing, cracks or a line rubbing on anything.

Need help choosing between the 3″ and 4″ axle kits? Send us your VIN and we'll confirm the right one.

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