Air Tank Check Valves

[WALT888]

RE: 2006 40DS04 Spartan Moutntain Master Chassis

In St. Paul I got a procedure from Spartan for draining air system
tanks. I performed the procedure while the MH was on leveling jacks
and built the air up to 90-100 lbs. At step 7 I emptied the supply
tank by pulling the clear ejector cable. Per step 8 the air pressure
should read the same as started. However my rear air gauge had dropped
to slightly under 65 lbs. At step 9 I drained the primary tank by
pulling the green cable. Step 10 says the rear air gauge should now
read 0 and the front should still read the same as started. However,
my front air gauge went to 0 and the rear remained at slightly under
65. I performed the process two times to verify that I was following
it correctley and it repeated. What experience have other owners had?
Although I have no other air problems and everything seems to be
working correctly is this serious and an indication that the check
valves have failed? or somethin else? Can the SMI air system that was
added to the read affect the check valves or the operation of this
procedure?

Thanks.... WALT

[Al_M]

Walt,
Walt,

I just had a problem with my air system. I started with similar
symptoms with the "rear" guage dropping to 65PSI when the clear cable
was pulled. The terms "front and rear" are somewhat misleading. The
65 PSI reading indicates that the check valve is working. As I
understand it, the "front" (Secondary - Red) supplies the suspension
and the "rear" (Primary - Green) the brakes.

Checking with Spartan my first problem was that the "rear and front"
gauges were cross wired, apparently when the recall to insert a new
wiring harness to correct the alarm point as required by Federal
Regulations.

Spartan told me that the air suspension should be filled before the
test. If your leveling system is like mine the jacks must be
retracted to inflate the suspension bags. This requires some extra
care when pulling the cables. If there is a leak in the suspension
system the coach will drop down. If the suspension stays up then it
is likely a problem with the braking system.

Did you have the Spartan recommended protection system installed
before connecting up the SMI braking system or did you directly tap
the rear brake line?

Once I got the gauge wiring problem straightened out the problem
determination was straight forward. My problem ended up being a
leaking rear ride height valve, which I understand is a common cause
of air suspension system problems. I did not even need to mix up soap
bubbles. I could feel the air leaking from the valve bleed hose. The
repair took about 1.5 hours including checking and resetting the ride
height front and rear.

Al

[Bishop at Supreme RV Service]

Walt,
Al is right on the money. It wasn't that uncommon to see those two
gauges cross wired. They are two identical connections sitting side by
side on the front fire wall. That is the most likely source of your
decrepency.
Bishop

> >                           Thanks....                    WALT- Hide quoted text -
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[WALT888]

Bishop,

Thanks for the input. I figured that the Step 9 and 10 problem
was related to wiring or labeling but what about the first step at 7
where when I empty the primary tank and the gauges are supposed to
remain at where they started at 90-110 lbs. My rear gauge ( or front
if they are mis-wired) drops to 65?? If the "real" rear dropped to 65
instead of remaining higher i would assume the SMI addition was the
culprit but if is in fact the front air should I worry about the check
valve between the primary and secondary tank ?? or is it related to
the fact that I have the coach up on jacks and the air was dumped when
it was leveled??

Thanks........... WALT

On Dec 12, 6:44 am, Bishop at Supreme RV Service

> > - Show quoted text -- Hide quoted text -

[Al_M]

Walt,

At step 7 (from the article written by Mike O'Neil) you are draining
the air from the "wet" or supply tank, not the Primary tank. If all
is well the primary and secondary tanks will stay at full pressure.
When the gauges are properly wired the gauge labeled "front" on the
dash is the secondary tank and the gauge labeled "rear" is your
primary tank. I'm not sure where the terms "front" and "rear" come
from since, as it was explained to me by Spartan Tech, the primary
tank takes care of your brakes and the secondary tank your
suspension. To properly test your system you need to raise your jacks
and inflate your air suspension. A simple "eyeball" test is to check
if your body is dropping from it's normal driving position, indicating
a problem with the suspension air. This would be indicated by a drop
in pressure of the ""front" gauge. If the body drops the problem is
with a leak in the suspension system (bags, ride height valves,
etc.). You stated that your gauge indicates 65PSI. This seems to
indicate that the check valve at the "wet" tank is doing it's job and
that there is an air loss in the system. Again, you do need to raise
your jacks and inflate your suspension. Be careful! Use jack stands
if you don't have access to a pit.

Al