Air tank gauges

[Paulraymond]

I have a 2004 Northern Star and on my last trip my front tank air gauge would only register 65 psi while the rear tank registers 125 psi, has anyone else experienced this issue and how do I rectify it, any suggestions please.

Paul Holder

[Hoffs]

Turn your key to ACC so gauges and dash lights come on, pump your brakes till low air warning comes on, then start your coach and see if it fills back up.

[hewebb]

Ours did that. I switched the plug on the gauges to prove it was the gauge. I could not find a new one anywhere. Ended up getting one from: https://colawrvsalvage.com


I sent them photos of the defective one. The one they had matched the photos but the part number was different. I ordered it. It works.

[Paulraymond]

Originally Posted by hewebb

Ours did that. I switched the plug on the gauges to prove it was the gauge. I could not find a new one anywhere. Ended up getting one from: https://colawrvsalvage.com


I sent them photos of the defective one. The one they had matched the photos but the part number was different. I ordered it. It works.

I have a 2004 newmar northern star and I have started losing a few slats from the rear engine door, I contacted newmar parts and they told me that the part I needed is no longer available, does anyone know where I can get one?
I will try and post pictures.
Thanks.
Paul Holder.

Thanks I will try that, I thought it might be the gauge because the bus drivers fine, thanks again.

[Paulraymond]

Originally Posted by Paulraymond

I have a 2004 newmar northern star and I have started losing a few slats from the rear engine door, I contacted newmar parts and they told me that the part I needed is no longer available, does anyone know where I can get one?
I will try and post pictures.
Thanks.
Paul Holder.

Thanks I will try that, I thought it might be the gauge because the bus drivers fine, thanks again.

Also did you switch them on the dashboard?

[Gary RVRoamer]

The coach has a split system, with separate tanks for front and rear axles systems. The front system usually runs an air accessories as well, but they get shut off if the pressure drops to about 65 psi (the minimum pressure for air brake operation). Since your front tank is dropping to the protected minimum level, my guess is you have a major air leak in some auxiliary air function, e.g. an air horn or an accessory air tap.


This article from Winnebago is not overly technical and covers the air system basics nicely. It uses the terms primary and secondary, but explains that primary is the rear and secondary the front. [Winnebago uses Freightliner chassis.]


https://winnebagoind.com/resources/s...%20Systems.pdf

[Paulraymond]

I tried it today but it didn't fix it, but thanks anyway.

[Gary RVRoamer]

There is no magic to finding a leak - just grunt work. Air the system up as much as it will and walk around and/or get underneath to listen for air leaks. Have a soapy water spray handy to isolate it.



Does the front tank ever get to 125 psi (the normal level)? If not, its a massive leak hat exceeds the compressor output flow. Pretty rare. If the system initially gets to 125 buy later drops to 65 with engine running, it's still a fairly large leak. If the system stays at 125 with the engine running, then it's a smaller leak and the compressor can keep up with it. It's not unusual for air pressure to bleed off once the engine is shut down - even a tiny leak will cause that.

[Paulraymond]

Originally Posted by Gary RVRoamer

There is no magic to finding a leak - just grunt work. Air the system up as much as it will and walk around and/or get underneath to listen for air leaks. Have a soapy water spray handy to isolate it.



Does the front tank ever get to 125 psi (the normal level)? If not, its a massive leak hat exceeds the compressor output flow. Pretty rare. If the system initially gets to 125 buy later drops to 65 with engine running, it's still a fairly large leak. If the system stays at 125 with the engine running, then it's a smaller leak and the compressor can keep up with it. It's not unusual for air pressure to bleed off once the engine is shut down - even a tiny leak will cause that.

Hi Gary,
No the front tank only gets to 65psi no matter how long I run the motor, I have walked the bus and cannot hear an air leak, someone at Freightliner suggested it could be a faulty air pressure gauge.
Thanks again for your help.

[twinboat]

If it was only the gauge, then the air dryer would purge when all tanks reached 125 PSI.

Does the air dryer purge ( blow off ) ?

[Paulraymond]

An update on my air pressure gauge problem, I got a new gauge off eBay installed it and the problem is still there, got a tech to look at it and he diagnosed it as a bad pressure switch, do I will order them tomorrow. [moderator edit].