2001 U320- 40' single drive axle, IFS. The two air guages on dash always read different pressures. One stays around 80-90 and the other is around 100lbs. Foretravel says there is nothing wrong. I still question why the different readings? Could one of the guages be faulty? Or is the reserve/pressure in one tank less than the other?
Any help would be appreciated.
Thanks,
David
One is reading the front air tank and the other is reading the rear air tank.
Are they different when the engine is running? Should be about the same being fed directly from the wet tank to Front and rear air tanks. Have you tried to reverse the gauges to see if you get the same readings?
Hi David,
I had the same question a few years ago so I had tech Bob at FOT make them even. It was odd to always see them uneven. Not that it makes any difference what so ever - I think he merely adjusted something forabout 20 minutes to make me happy. He made no changes to the gauges.
Great info, so on my 95 U300 which needle is front air tank, Red or White..???
Hans
Look close, they should be marked P. & S. as in primary & secondary.
This is a issue with 2001. They do not make the gauges any longer and they are electrical. You can not just remove them or you get the level light so I tee off the tanks and put in VDO mechanical gauges in their place. Now i have the right reading.
I got two mechanical gauges in the the dash to replace the two electrical gauges that were no longer available (one had gone "bad"). Mine read within a psi or two of each other.
mike
Mike and John;
I like the idea of replacing because it drives me a little crazy as well.
Where did you guys get the guages? Made by Stewart Warner?
Mike I did not understand what you meant by t-off?
Thanks,
David
John wrote you about the t-off but I am going to guess that he is saying off of the line from the tanks?
As for mine, we could not replace the Stewart Warner electrical gauge so MOT got a mechanical one. That they would match gauges in the dash, they just did both with mechanical. One difference is that I can read the gauges while parked at a site and not turn on the key.
Interesting is that in chasing down leaks we parked for nearly two weeks and the psi only declined about 70 psi while parked. In the past I could go to almost a 110 psi decline in four days. This in some part I am sure was due to replacing the air activated fold down step which (those) has a reputation of leaking cylinders.
Hope this helps you, Mike
Like our cars, our motorhomes have Dual Air Brake System, which consists of two separate air brake systems that use a single set of brake controls. It is designed to retain braking ability in the event one system fails. Thus one is primary and one is secondary. Doesn't really matter where they are at. Usually three all together. One primary, one secondary, and one wet.
Air Brakes 101 (http://www.newbiedriver.com/abcsupdates/airbrakes101.htm)
Thanks Pat, so the red and white needles represent Primary and Secondary, still not sure which is which red/white needle.??
Sorry for the lack of brain power here.. ;D
Hans
I'll bet white is primary and Red is secondary. Red meaning warning.
Pat, makes sense red being a warning color.
Thanks Again
93 u300
red is for rear systems ( brakes etc ) ( also right tank in front )
white is for every thing else.
Thanks Bill.!
Mike,
I am going to MOT at end of the month anyway. I will call ahead and see if they keep guages in stock.
Thanks,
David
David, was out at MOT to see progress on our annual maintenance and getting the MCD shades.
I talked to Allen in Parts and he said that if you would call in advance he would have the gauges when you arrive. He said that they are getting commonly desired sufficiently now that he should be stocking them, and will do so.
But I think please call him first if you would be on a tight schedule, not want to rely upon getting them sent to MOT while you waited a day or so?
You can read Allen (MOT) 936-564-1112
If you want photos of how they look, let me know. I think fine, but this adds two silverish bezels to an other wise black dash (SW gauges)
Mike