Trailer Air Bags: Leaks, Ride Height, and Replacement
Air bag failure sags the trailer and damages cargo. We cover finding the leak and when to replace vs. repair.
Finding a leaking air bag
A leaking air bag sags the trailer on one side or drops it overnight. We build air, shut down, and soapy-water each bag — leaks usually show at the bead (the rubber-to-metal crimp), at a chafed spot on the bag, or at the top/bottom fitting. A bag that's separated at the bead is failed and needs replacement; a slow leak at a fitting may be a connection, not the bag.
Ride height after replacement
Replacing an air bag without re-checking ride height is a common mistake. The new bag's free height can sit the trailer at a different level until the height control valve settles. We set ride height to spec after any bag replacement and verify the leveling valve isn't the original cause of the failure (a sticking valve over-pressures bags and shortens their life).
When to replace in pairs
On a tandem axle, if one bag has failed from age and the adjacent bag is the same vintage, we recommend replacing the pair on that axle to keep the trailer level and avoid a repeat failure. We carry common air bag sizes on mobile units; most replacements are done roadside or at your yard.
Our mobile diesel technicians carry the tools and parts to diagnose and fix this on the shoulder or at your yard — 24/7/365 across Colorado, Wyoming, and Texas.
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