I have searched earlier postings and find comments about the governer and mostly "governer failure", as in low or no air pressure. My question is prompted by high pressure.
Noted on start-up, after pressure build-up: the front air system gauge will settle out about 125PSI, but the Rear will peg the needle at 150. This is while sitting and idling.
After I put it in gear and back out of my spot, with multiple brake applications while backing out, the pressure will in the Rear System per the gauge will return to the same normal range as the Front System gauge.
Is this a sign I should premptively replacew the Govener?
Coach is a 2003 U-270, 34-ft, 93,000mi, ISL-400, single slide.
Comments? Advice?
May be an inaccurate gauge, since air compressor feeds both reserve air tanks.
Just my thoughts.
Agree, if the actual pressure went to 150 psi, it would open the safety releif valve, you would hear it very easy. So I feel the gauge/sender for that gauge is faulty.
I had this problem last year and it was the govenor all plugged up with Dessicant from a faulty air drier. Replaced both and all ok. I rebuilt the Gov' with new o rings and cleaned it out for a spare
John H
Thanks to all - I think I will replace the Governer "just in case".
As I understand the air system, the D2 governer located on the compressors kick in at low pressure, out at high, and allows the compressor to restart under no load conditions. When mine started failing, it was not kicking out, and allowing too high of pressure to show on the gauge, and both needles (above the setting of 125#). I replaced mine, and bought a second as a spare, as they are about $35 for rebuild units, and about the size of a frozen juice can to store and carry.
You mention two different pressures showing on the dash gauges, one is for the front and one the rear brake systems. Sure don't think the governer could cause that sort of problem. As they are cheap, sometimes not hard to replace, why not? But I would be surprise to see that fixes anything. Study of the air system diagrams, shows lots of connectors, valves, check valves, and parts to the coach. Add to that the whole separate air bag system, you have lots of parts.
Interesting to read that John found dryer dessicant from a faulty air drier in his. I thought the air goes to the dryer, was always under pressure. But there must have been a faulty check valve to allow back pressures back thru the dryer. There are check valves to not let the air system loose pressure once it is in the wet or dry tanks. There are many check valves to keep the two brake systems apart, so that you would always have at least front or rear brakes even when the other system is leaking off, even if it is the air bag system.
Dave , You are correct on the governor issue, one point of interest, in the old days before the dryers, they used alcohol injection into the air system to control the ice up issue. the governor has a few ports most are plugged off, but you can have material injected into the air system if you have things hooked up wrong. So I could believe on an improper plumbed governor, you could get dirt into the system.
Why having the correct air line diagram is important and better than guessing.
FWIW
The coach in question has electric senders for the pressure guages so could have either a bad sensor or a bad guage. On the older coaches the guages had an air line form the tank to the guage.