How to Install an Aluminium Air Tank (2026 Guide)
Fitting an aluminium air tank properly is what separates a reliable onboard air system from one that leaks, cycles constantly, or shakes itself loose within a few months. This guide walks through mounting, plumbing, and pressure setup so the tank does its job of storing compressed air for load assist airbags, tyre inflation, or air lockers.
- How to install an aluminium air tank starts with a secure mount point clear of moving parts and heat.
- A 2 gallon tank suits single-accessory tyre inflation; a 5 gallon tank suits load assist plus air lockers together.
- Teflon tape on every NPT port prevents the most common onboard air fault: slow pressure leaks.
- Budget 90 to 120 minutes for a first-time install with a drill, spanners and thread sealant in 2026.
Why this matters
An onboard air compressor on its own struggles to keep up with demand. It has to switch on every time you need air, and it cycles constantly under sustained use like reseating a bead or running an air locker.
An aluminium air tank stores compressed air ahead of time. The compressor tops it up in the background, and the tank supplies the burst of air you actually need, right when you need it.
For Boss Air Suspension load assist customers, a tank also smooths out pressure delivery to the airbags, which matters when you're adjusting ride height at the side of the road with a trailer hooked up. Get the tank mounted and plumbed correctly in 2026 and it should run trouble-free for years.
What you'll need
- An aluminium air tank sized to your setup — the 5 gallon aluminium air tank suits load assist plus a second accessory like an air locker
- Drill with a step bit or hole saw matched to your mounting bracket
- Mounting brackets or P-clamps rated for vibration, not just cable ties
- Self-tapping screws, rivnuts, or bolts depending on the mounting surface
- Teflon tape or liquid thread sealant for every NPT port
- Push-to-connect fittings and air line sized to match your compressor and accessories
- A pressure switch or gauge to monitor tank pressure
- A safety relief valve rated below the tank's maximum working pressure
- Wire loom or conduit to protect any electrical runs near the tank
- Basic spanners, a torque-appropriate socket set, and a permanent marker for layout
The steps
1. Choose the mounting location
Pick a spot clear of moving suspension components, exhaust heat, and anywhere road debris can strike the tank directly. Under the tray, inside a canopy, or behind the rear bar are the usual spots on utes and 4WDs.
The location has to give you access to all the tank's ports for plumbing and future servicing. A tank you can't reach without removing the tray is a tank that never gets checked.
Common mistake: mounting the tank flat against a panel with no clearance for the fittings on the ports, which forces awkward bends in the air line and stresses the fittings over time.
2. Drill and secure the mounting brackets
Mark the bracket holes, drill pilot holes, then step up to the final size for your fasteners. Fit rivnuts if you're mounting into thin sheet metal, since self-tapping screws alone won't hold under vibration.
Tighten brackets so the tank is rigid with zero movement when pushed by hand. A tank that shifts even a few millimetres will eventually wear through paint and start corroding at the contact points.
Expected outcome: the tank sits solid with no flex, ready for plumbing.
3. Fit the ports and safety valve
Wrap Teflon tape clockwise around every NPT thread before fitting a port, fitting, or gauge. Two to three wraps is standard — too little and it won't seal, too much and it can shred into the airline.
Fit the safety relief valve to a dedicated port rated below the tank's maximum working pressure. This is the part most people skip, and it's the one that matters most if a regulator or switch ever fails.
Common mistake: over-tightening fittings past hand-tight plus a quarter turn with a spanner, which cracks aluminium ports.
4. Run the air line from the compressor
Route the line from the compressor outlet to the tank's inlet port, keeping it clear of the driveshaft, exhaust, and any sharp edges. Secure it every 300-400mm with clips so it doesn't chafe.
Use push-to-connect fittings sized to match your line diameter exactly — a loose fit here is the second most common source of leaks after the port threads themselves.
Expected outcome: the compressor can fill the tank without any airflow restriction along the run.
5. Install the pressure switch or gauge
Fit the pressure switch to its dedicated port and wire it to cut the compressor out at your chosen upper limit and back in at the lower limit. Most setups run somewhere between 100 and 150 PSI depending on the compressor and tank rating.
A gauge next to the switch lets you confirm the system is actually cycling where it's set, rather than trusting the switch blind.
Common mistake: wiring the switch normally-open when the compressor circuit expects normally-closed, which leaves the compressor running continuously.
6. Connect the outlet lines to accessories
Run separate lines from the tank's remaining ports to each accessory — load assist airbags, tyre inflation point, or air locker solenoids. Label each line at both ends before you close anything up.
Keep outlet lines as short and direct as practical. Long, looping runs add lag between opening a valve and air actually arriving.
Expected outcome: each accessory gets air independently without cross-feeding issues.
7. Pressure test the system
Fill the tank to its working pressure and leave it overnight. Check the gauge again in the morning — a drop of more than a few PSI points to a leak somewhere in the ports, fittings, or line joins.
Use a soapy water spray on every joint if you can't find the leak by ear. Bubbles show you exactly where the seal has failed.
Common mistake: testing for five minutes and calling it done. Slow leaks only show up over hours, not minutes.
8. Secure and protect all lines
Go back over every line and bracket once the system holds pressure overnight. Re-torque any fasteners that vibration may have loosened during the test, and make sure no line rests against a hot or moving part.
Expected outcome: a tank and plumbing setup that's ready for daily use without further attention.
“If the tank rattles against the chassis, it's not mounted -- it's just resting.”
Troubleshooting
- Slow leak at a port — remove the fitting, clean off old sealant, and re-wrap Teflon tape two to three times before refitting. A single wrap rarely seals aluminium threads under vibration.
- Tank won't hold pressure overnight — isolate sections of the system one at a time with a shut-off valve to find which branch is losing air rather than replacing parts blindly.
- Compressor cycles too often — check the pressure switch settings first. A cut-in point set too close to the cut-out forces short, frequent cycles that wear the compressor faster.
- Pressure switch doesn't trigger the compressor — confirm the wiring matches normally-open or normally-closed as required, and check the fuse before assuming the switch has failed.
- Rattling or vibration noise — the tank isn't fully secured. Re-check bracket torque and add a rubber isolation strip between the tank and any metal mounting surface.
- Corrosion around the tank ports — usually from moisture sitting in the airline. A water trap fitted between the compressor and tank stops this before it starts.
Tools and resources
- Drill, step bit, and rivnut tool for mounting
- Teflon tape and a spare tube of thread sealant
- Soapy water spray bottle for leak testing
- Pressure gauge to confirm switch settings are accurate
- The airbag fitting kit covers common line and fitting sizes if you're plumbing load assist airbags off the same tank
What to do next
Once the tank is mounted and pressure-tested, the next decision is whether the size you fitted actually matches your accessory load. A tank that's too small for an air locker plus tyre inflation will cycle the compressor constantly, even with everything installed correctly.
FAQ
How do I install an aluminium air tank for onboard air?
Mount the tank securely away from heat and moving parts, seal every port with Teflon tape, plumb the compressor inlet and accessory outlets, then pressure test overnight before use. Most first-time installs take 90 to 120 minutes in 2026 with basic hand tools.
What size aluminium air tank do I need?
A 2 gallon tank covers a single accessory like tyre inflation, while a 5 gallon tank suits load assist airbags running alongside an air locker or second accessory. Match tank size to how many accessories draw air at once, not just total vehicle size.
Where should an onboard air tank be mounted?
Mount it clear of the driveshaft, exhaust heat, and direct road debris, with all ports accessible for future servicing. Under the tray or inside a canopy are the two most common mounting points on 4WDs and utes.
Do I need a pressure switch with an air tank?
Yes, a pressure switch automates when the compressor cuts in and out so the tank stays within a safe working range without manual monitoring. Most setups run the switch between 100 and 150 PSI depending on the tank and compressor rating.
Why is my air tank losing pressure overnight?
A pressure drop overnight almost always points to a leak at a port thread or fitting join rather than a faulty tank. Spray soapy water on every joint to find the exact leak point before replacing anything.
Can an aluminium air tank feed both load assist airbags and tyre inflation?
Yes, a single tank can feed multiple outlets as long as it's sized for the combined draw and each line runs to its own accessory. A 5 gallon tank is a common choice for this kind of dual-accessory setup.
What thread sealant should I use on an air tank?
Teflon tape wrapped two to three times clockwise, or a liquid thread sealant rated for compressed air, seals NPT threads reliably. Skipping sealant or using too little is the most common cause of slow leaks at the tank ports.
How often should I check an onboard air tank after installation?
Check pressure and listen for compressor cycling weekly for the first month, then monthly once the system has proven stable. A tank installed correctly in 2026 should need little more than the occasional visual check after that.
One last thing
Most tank installs that fail don't fail at the tank — they fail at the ports, because Teflon tape gets skipped or under-wrapped on one fitting out of a dozen. Check every single thread before you close the job up, not just the ones that look loose.
