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+--- Thread: When to replace suspension air bags? (/showthread.php?tid=1096)
When to replace suspension air bags? - davidbrady - 04-13-2018 11:23
In my 14 years of bus ownership, I've never replaced an air bag. There are a differing philosophies floating about regarding replacement. Some adhere to the 10 year "zero-out" rule which necessitates the disposal of otherwise good parts. This appears to be driven by the desire not to be left stranded with a blow out during a trip; although, they rarely blow out and instead tend to leak with the leak progression offering plenty of time to get to a service facility. Because of this, another replacement philosophy is to leave them in service until the bus develops the leans. When this occurs the offending bag can be replaced along with all the Norgrens at that corner, or one can use this as a signal to replace all the air bags. The steer axle air bags work the hardest, given their higher pressures needed to support the weight. As such, a steer axle air bag leak may not be indicative of impending drive and tag axle bag failure. My mechanics at Burke Christian Tours told me that all they ever do is replace the steer axle air bags and that the drive and tag axles last a long time and hardly ever need replacing. This implies that these air bags may last the lifetime of the coach. Of course, air bag lifetime is certainly tied to how the bus is used and how it is stored and storage ambient conditions. Maybe this is why I've never replaced a bag; my coaches have always been stored indoors in climate controlled conditions away from industrial ozone creating devices, welders etc.