Chassis & Handling

[gpafox@att.net]

I have a air leak in the suspension and can seem to find it. I did find a major leak and had it fixed by a mechanic.

The Psi drops from 120 to 55 over night. Th air bags do not seem to deflate so any ideas on finding  the leak or is this normal

[Dr4Film]

That amount of air tank leak-down has been my norm for years.  I had Alliance Coach spend about three hours looking for leaks and they couldn't find even ONE.

I haven't had anyone else even look and I am too large to get under there and look for my self.

So it is what it is.

[jpsbabiarz]

Check your pop off valve on air tank, my was leaking ever so slightly, replaced it holds air fine now.

Jim B

O4 Windsor

[David Pratt]

Monacoers] Coach Air Suspension Allowable Leak  Down

I was going through some old Monaco Inc. Files and found this information that was sent to me by Bill D. years ago and thought it might be of interest to the Group as this question of what is the allowable leak down rate on a coach is often discussed here on the Forum.

D.O.T. Standard Allowable Leak Down. Rev. 06-03-2004

The Department of Transportation (D.O.T.) standard for allowable leak down in the air systems is as follows.

1. A 4 PSI drop in the front air system in a 2 minute time period is allowed.

2. A 4 PSI drop in the rear air system in a 2 minute time period is allowed.

This translates into a 120 PSI drop in a one hour time period. In other words, both needles would be allowed to go to zero PSI in one hour. All of the control valves, relay valves, check valves, etc., have allowable leak rates, even for new components. It is not within the Scope of Monaco Inc., or any Manufacturer, to completely eliminate air leaks. Therefore, the D.O.T. sets the standard for allowable leak down rules in the interest of safety. However, Monaco, Inc.'s leak down rate is set as follows:

Monaco, Inc. Allowable Leak Down

1. A 6 PSI drop in the front air system in a one hour time period.

2. A 6 PSI drop in the rear air system in a one hour time period.

This translates into an approximate 60 PSI allowable leak down rate, for each air system, in the overnight park mode(10 Hours). This is an extremely small air leak. The Monaco, Inc. and other Manufactures standard is 20 times more stringent than the D.O.T. required safety standards, which allows 120 PSI per hour.

This Article is also posted in the Articles Section under Technical Papers on this Forum

 

[Steven P]

I just replaced 3 leaking fittings on my front tank.   Before this, my pressure would drop to 0 overnight.  Now I lost about 35psi in 12 or so hours so I'm happy about that.   I went under the coach with soapy water and sprayed all the front fittings to find those leaks.   I haven't looked at the rear.  But one suggestion:  check your parking brake at the dash.   Mine had a small leak there too.  

[Paul A.]

Our 07 Executive has petcocks on the air tanks to drain any condensation. They did NOT have a 90  degree dead stop, so one had to be careful when using. I replaced them with brass ones that had a dead stop.

Paul A

[MSHappyCampers]

My air pressure leaks down pretty fast too!  My aux compressor for the leveling system seems to work fine so I don't worry about it! 🙂

Joe