Air bleed off

[Whaley]

I know it's been hit a thousands time I just can't find the info I'm looking for I have an mci 8 and I'm trying to see how much air bleed off is normal I would love for some tune frames on building air and how long it bleeds off.

[richard5933]

Are you talking about the pressure shown on the gauge or how long it takes for the air suspension to settle?

My bus will hold air on the gauge for a few hours before creeping under 90psi, and then it will drop to about 40-50 by the next morning. The air suspension will stay up for months.

A really good place to start is to learn how to do an airbrake/air system safety leak down test. Lots of good information in the CDL manual and lots of good information online.

These tests will give you a specific number of how many PSI drop is permitted in a minute, both while holding the brake pedal down and while the bus is just sitting.

Here's one example: https://www.youtube.com/watch?v=MbnVGWqDHIU

[Whaley]

Mine drops to 90 in 3.5 hrs
And is at 30 psi in 18 hrs
But my suspension starts dropping once it drops below 90.
It holds 30 for months