Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 13, 2025 ...

Front Air tank not holding air

July 25, 2019, 10:38:31 am

Re-leveled the coach this morning and noticed that the Right air gauge on the instrument panel is not increasing air pressure above 35#+/-.

Was able to level the coach but it appears that either the tank air indicator gauge is not functioning correctly or am losing air in the tank.  The gauge pressure does not appear to drop below this level.  It also does not appear to increase to the normal level of 100#psi+/- when energized.

Will get under the coach in the next week or so to check for leaks on all fittings from the front tank through the manifold.

Thoughts?  Check valves?

Again I thank you all for your support and input.

 

Quote Selected

Re: Front Air tank not holding air

Reply #1 – July 25, 2019, 10:49:13 am

My first guess would be a faulty gauge or faulty pressure sender.  If you have electric (as opposed to mechanical) air pressure gauges, you might also have the troublesome "gray box" that translates the pressure sender signal to a reading on your gauge.

See thread below, starting at Reply #7:

Air Pressure

Quote Selected

Re: Front Air tank not holding air

Reply #2 – July 25, 2019, 11:05:45 am

Thank you Sir -

Quote Selected

Re: Front Air tank not holding air

Reply #3 – July 25, 2019, 11:19:06 am

Scott,

I don't know how easy it is to get at your front and rear brake tanks.  On my GV, of course, very easy.  Anyway, I installed a male air hose quick connect fitting in the drain valves on both my brake tanks.  These are handy for two reasons.

First, if I (like you) suspected a problem with one of my dash air pressure gauges, in my tool box I carry a pressure gauge screwed into a female air hose quick connect.  All I have to do is pop the gauge on the tank drain valve and I can read the tank pressure directly.  This would be helpful in your current problem diagnosis.

The second reason is I can connect a air hose to either of the brake tanks to fill up vehicle tires from the front end of the coach. 

Quote Selected

Re: Front Air tank not holding air

Reply #4 – July 25, 2019, 11:26:41 am

Hey Check -

I'll be under there anyway - sound like a good thing to do. 

Quote Selected

Re: Front Air tank not holding air

Reply #5 – July 25, 2019, 03:18:14 pm

Scott,  your coach probably got rid if the electronic air pressure gauges and went to direct read mechanical gauges.  The electronic ones read zero with the ignition off.  If your coach's air system has not been altered and the check valves are working then the HWH compressor will not add air to the front or rear service tanks. It adds air to the HWH tank and from their to the slide bladder manifold(s) and to the front and rear leveling manifolds. 

Air from the front and rear service tanks will also go to the front and rear leveling manifolds through the pressure protection valve.  When the coach is running this is the primary air sours for ride height and leveling.

In your coach the aux air connection in the LP bay is fed from the rear tank after the PPV.  This tank is connected to the wet tank and the engine compressor but not the HWH compressor. In later years the HWH compressor is bigger and has a switch operated solenoid valve that when open feed the wet tank and then the front and rear service tanks and eventually the Aux air connection.

A common source of leakdown in the front tank is the step cover slide and the fold down step.

Check valves and the PPV are probably due for replacement and will likely solve a big chunk of the air leaks.  Tighten up every fitting you can get to.

Quote Selected

Re: Front Air tank not holding air

Reply #6 – July 30, 2019, 07:34:27 pm

Hey Roger & Chuck -

Sorry I hadn't commented on this earlier. 
It's taken me a while to get back to this.
Dash PSI gauges were replaced by PO a while back with mechanical.
Got a couple of other things to check.

Ordering parts in the next day or two to replace the check valves and stuff on the front end.  Thankfully, we have a son-in-law that knows how to wrench and is willing to help or we'd be off to coach buck city.

What would I do without your guys?

Thanks 

Quote Selected