-
– All 3 Air Tanks Leaking Down Same Rate RESOLVED
After seeking a solution for about two years, it was Donnie Meyers who stated he had tracked this issue down to a slightly leaking PR-2 pressure protection valve. Replaced it and no more all 3 air tanks leaking down at same rate.
In my case, the PR-2 is mounted to one end of the aux air tank, and the aux air tank is mounted to the ceiling of the spare tire bay.
I removed a cruise air in need of a new compressor (and replaced it along with new capacitors and a new filter dryer) which gave me access to the aux air tank.
I removed the aux tank, repainted it, changed original push-in fittings to compression, REPLACED the PR-2 valve and remote mounted it from the end of the aux tank to the back wall of the steering bay AND ALL THREE TANKS NO LONGER LEAK DOWN AT THE SAME RATE 🙂
I relocated the PR-2 valve to make it easy for future replacement.
How this was indeed the fix, I cannot comprehend as the Prevost air diagram gives no clue on how this could be a possibility…
-
12 Replies
-
Excellent work. It feels good removing weak links with those push in connectors.
So you didn’t replace the valve and the issue went away just with a small reconfiguration?
-
Was that the PR-2 valve on the end of the Aux tank under the front of the bus?
-
Good Morning Art – I completely left out the fact that replacing the PR-2 valve was the fix!
I edited the post to include the fact the PR-2 was replaced.
THANK YOU for catching that!
-
What you have explained here is also an indication the check valves at the front and rear air tank have failed. Otherwise the air could not get to that valve. You may want to check them.
-
Good Morning Mikee and THANK YOU for your reply – It defies logic and you are 100% correct in that should be the case, yet neither check valve has failed.
I cannot comprehend why changing that PR-2 valve would get the result because no where on the air diagram for my bus do the aux, primary and secondary air lines “intersect”. It makes absolutely no logical sense.
Only would it make since if BOTH my primary and secondary one-way check valves had simultaneously failed.
I have performed tank draining / check valve testing in the proper sequence recently and a few times in the past after learning about it from this group and the check valves work and the tanks do not drain except by the petcock drain valve.
I called Haldex customer support to ask a couple of questions about the PR-2 and the tech stated exactly what you state!
Another way during this process that I tested the primary tank check valve was due to the fact I did not drain the main tank prior to disconnecting the aux air tank supply which comes from the main tank via a supply tee at the secondary tank that feeds both the secondary and aux tanks…and, the main tank itself did not leak down.
You have a so much more experience than me… do you think I have covered my bases? Any testing I have missed?
THANK YOU! Jeff…
-
The parking brake valve can also cause the front and rear tank to drain.
If you changed only the one valve and the issue went away 100% is is apparent that was the issue.
That being said, those check valves keep air in the tank and are supposed to be the only connection to the common supply line from the compressor, dryer, air tank, line.
You may want to look around and see if some creative air line plumbing has been done to circumvent the check valves.
Happy hunting
-
Jeff:
Take a trip north when it’s cold and you will find more leaks!
In as much as I know I will never stop all the leaks long term, I have made it a mission to try (I know, there is better ways I can spend my time).
I have replaced all the air bags, all the Norgen valves, about 90% of the push on fittings, all the PSI adjustable valves, interior sliding door valve, and just about any other fittings I find (the quick connections for a portable air hose plug-in’s were a leaking source too).
I have (had) my leaking down to the point that my primary and secondary tanks hold air for over two months and my Aux tank would hold for about a week. THEN I took a trip north last November. When I went to depart, I couldn’t get the air steering wheel adjustment to lock. Finally got it to lock for the drive home then replaced it. Now leaks are minimized again.
Air adjust for the steering wheel never showed up until a cold morning up north. Probably would have never found it otherwise. The chase never seems to end. I also noticed the safety valves WOULD leak back long term but WOULD NOT leak back with a fast (catastrophic) leak like experienced during a leak test.
Chuck
-
Good Info Mikee & Chuck – thank you very much.
Will enjoy until the next leak appears!
-
What is the tank leak down test? I replaced both my main tank check valves 4or 5 years ago but recently all of my tanks were leaking down at the same time, So I let air out of aux tank and the secondary tank followed so I cleaned out secondary check valve and it’s way better. I might change out the PP-1 valve just for the heck of it I did it when I 1st bought 8 years ago. I tend to use Bendix Products ??
-
Good Morning Art – I definitely like going back with OEM stuff, so almost always purchase straight from Prevost. Their pricing on the PR-2 valve was very good.
You and Mikee have caused me to think about the primary and secondary tank check valves. Like my SLOW leaking PR-2 valve, now obviously not leaking, perhaps they too are leaking slowly therefore will add them to the list to replace.
Perhaps as Mikee said (and may you also – cannot remember) it makes since they too may have a VERY slow leak.
Here is the link to the test.
-
Jeff! When I did mine after I removed old ones had ordered new check valves I took one apart and they are definitely serviceable you could leave main body and unscrew inners clean spring and plastic plunger real simple no O-rings no seals simple
-
THANK YOU Art! I will print what you said (so I won’t forget lol) and take a look at them 🙂
Log in to reply.