Suspension lean solved...what I learned

[Scott Forman]

Thought I would share my findings with the group regarding the
leaning air suspension I have talked about here lately.

I got the coach back yesterday after having a rough-looking airbag
replaced on the left front (for review-the front axle was listing to
the left while the rear was properly level). The old bag that was
replaced appeared to still be holding air (no audible leaking noise
and no bubbling when soaped), but did have a large tear in the outer
bladder that had exposed the inner bladder to the environment.
Holding air or not, I figured its days were numbered, so I opted to
replace.

The suspension now operates correctly. Since the only thing that has
changed is the replaced bag, I have developed a theory on what was
causing my lean:

I suspect that the torn bag was seeping air even though I could find
no evidence of it. As a result of this, I believe that when the
suspension was airing up from a dump position and the front leveling
valve was calling for air to lift the front axle, air would fill the
right side bags faster than the left side, casuing the lean. The
front leveling valve only knows up and down, not side to side, so it
just keeps pumping until a height is reached. If it lifts unevenly,
it doesn't care, it just wants to reach a height. So the right side
was getting over-inflated before the left could catch up.

Meanwhile, on the rear axle, the rear valves that control side-to-
side were oblivious to what was happening. The lean was pronounced
in the front, but 30 feet back at the rear axle, the lean was much
less dramatic, so the rear valves, though functioning correctly,
weren't adjusting enough to correct it.

So that's my theory based on what I have learned. My escapades
chasing gremlins in the air suspension have given me a lot of respect
for the complexity and engineering that went into the system. It's a
living thing...it breathes, it consumes, and when you can't find the
problem, it seems like it hates. Many different things that all have
to work together or the whole thing fritzes out.

Scott Forman
'Tiger Pride'
82 FC35RB
Memphis