Troubleshooting
Most common reasons your air suspension leaks
Almost every air suspension leak traces back to one of four things — threaded fittings, push-to-connect connections, air line cuts, or line abrasion. All of them are fixable once you know what to look for. Here's how to identify and address each one.
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Threaded fittings installed or prepped poorly
Threaded NPT (National Pipe Taper thread) fittings are used at your tank, compressor, manifold, air suspension, and any other component with a threaded port. They end up being a pretty common source of leaks in an air suspension system and almost always because of installation errors rather than defective parts.
Two main things cause threaded fitting leaks: improper thread tape or sealant application and over or under tightening. Threaded fittings like NPT fittings seal on the taper of the thread, not on a gasket, which means thread tape or sealant is required to fill the gaps in that taper and create an airtight seal. Skip the tape and you'll leak. Use too much or apply it incorrectly and you'll also get a leak.
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Always use thread tape or sealant
Wrap thread tape clockwise when looking at the male end of the fitting. Typically 3 wraps on a fitting with "clean" threads will do the trick. If your fitting already has some sealant on it from the factory, 1 to 2 wraps with thread tape will be enough. You can also use a thread sealant rated for air systems but you'll need to wait for the sealant to cure before pressurizing the system. If you're chasing a leak at a threaded fitting, back it out, re-tape, and reinstall.
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Don't over or under tighten fittings
Hand tight plus one to two turns with a wrench is the right range. Over tightening can crack the port or distort the threads. Under tightening doesn't seat the fitting properly. If you're feeling excessive resistance, never force a fitting into a port. Back it out, check the threads of the port, and try again.
Push-to-connect fittings and PTC bite
Push-to-connect fittings are the easiest type of fitting to work with in air suspension systems - insert the air line, and it locks, no tools required. They work reliably when installed correctly but there are two common reasons where these fittings can leak.
The first is simply not having the air line fully seated into the fitting. A line that looks inserted might only be partially installed. It needs to be pushed all the way until it stops before the internal grab ring engages. A partially seated line can hold pressure for a while before developing a slow leak. If you have a PTC leak, push the air line in harder before assuming anything else.
The second is PTC bite. Over time, and especially after repeatedly removing and reinserting the air line, the internal grab ring leaves a ring of small gouges on the outer surface of the air line. These gouges weaken the seal at that point and eventually cause a leak. If you see a ring of marks on your line where a fitting was seated, that section of line needs to be cut off and reinserted fresh.
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Cut off PTC bite and reinsert
If you see a ring of bite marks on your air line, use an air line cutter to remove that section. Cut past the damaged area and reinsert the fresh end into the fitting. Don't try to push the bitten section back in and hope it seals, it most likely won't.
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Make sure the line is fully seated
Push the air line fully into the fitting until you feel the line stop. Tug the line back gently to confirm the grab ring has engaged. If it pulls out easily, it wasn't fully in. A fully seated air line should have some resistance when you tug it.
Good to know
To remove: depress the collet ring
PTC fittings have a collet ring which allows for easy air line removal from the fitting. Press the collet ring toward the fitting body while pulling the line out. Yanking the line without depressing the collet can damage the grab ring and cause the fitting to leak on the next insertion.
Good to know
Replace fittings that have been cycled many times
Push-to-connect fittings aren't designed for unlimited insertion cycles. A PTC fitting that has been connected and disconnected dozens of times may no longer grip (and seal) reliably. They're inexpensive so if you're chasing a leak and a fitting has a lot of cycles on it, it might be worth replacing it.
Poorly cut air lines
The quality of the cut on your air line matters more than you would expect. A jagged, or angled cut gives the o-ring inside of the PTC fitting an uneven surface to seal against - which will almost always result in a slow leak.
To prevent this from happening, you should use a dedicated air line cutter to get a perfectly flat, 90 degree cut, but if you're in a pinch using a sharp razor blade on a flat surface can work as well. A PTC fitting is designed to seal against a clean square cut. Give it that and it works reliably. Give it air line with an angled or crushed cut and you're setting yourself up for a leak.
Always use
An air line cutter
An air line cutter makes a clean, square cut in one motion without deforming the line. A sharp razor blade on a flat surface works well too. Scissors, wire cutters, or a utility knife dragged across the line all produce cuts that are too uneven to seal properly.
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Avoid crushed or angled air line ends
Some cutting tools, and dull blades pinch the line as they cut, leaving an oval cross section instead of round. Don't rush and cut your air line at an angle. It takes two seconds to do it properly. If your cut doesn't look perfectly straight, cut again. Good enough isn't worth it.
Line abrasion and heat damage
Air lines that weren't properly secured during installation or lines that come in contact with moving parts can eventually wear through and cause a leak. Heat from the exhaust or engine can cause lines to melt if they are mounted too close or come in contact with hot objects.
Prevent it
Secure lines at regular intervals during install
Clip or zip tie your air lines every 12-18 inches and use grommets anywhere a line passes through a body panel or over a metal edge. Time spent securing lines properly during the install is the best prevention against leaks. Abrasion / heat related leaks are almost always an install shortcut that shows up months later.
Fix it
Replace the damaged section and secure properly
Cut out the damaged section and replace it using union style PTC fittings when in a pinch. If you run into a leak due to abrasion or heat, it's best to rerun the entire line in a slightly different path to prevent it from happening again.
How to find a leak once you know it exists
If your system is losing pressure but you can't hear or feel where the leak is, soapy water is going to be your best friend. Mix some dish soap and water in a spray bottle and go to town. Spray all of your fittings, line connections, and anywhere you suspect a leak to be coming from. As long as the system is pressurized, bubbles will appear at any leak point.
Troubleshoot
How to find and fix an air ride leak
Step-by-step process for tracking down and sealing leaks once you've identified the area.