adjusting air govenor

with the adjustment on the govenor... there is a set screw in the center of a 7/16 nut, you have to loosen the nut to adjust the pressure, however, what I found when adjusting the govenor by turning counter clockwise then when tightening the nut to secure it's location, turning the nut to tighten, will turn the setting screw back clockwise & reduce the pressure setting, so you may have to turn adjustment screw a lil more than desired, or somehow hold the set screw in place while tightening the nut.

 

Doesn't seem to be any major leaks. I take weekends off and when I crank the truck on Monday morning it still has around 90 PSI.

 

I would if I could. I would have to stretch the frame to make room for one. The other truck has no problem hauling our stuff, same year, make and model. They are set up the same except for HP. One is at 550 while the other is still at the factory 475 HP.

 

Running down the road, loaded or empty, bob tail or with the trailer. When the compressor kicks in, it cuts out at 120 PSI, the air dryer releases, and a second or two later the PSI drops back to 100 PSI.
I don't understand what causes this 20 PSI drop. I do not have any leaks that I can hear. Some of my loads are well over 100,000 pounds gross and when I get into the hills or traffic, I am not comfortable with only 100 PSI. I would like the compressor to kick in around 110 and cut out around 130-135 and maintain more 115-120 PSI available. Maybe instead of adjusting the governor that I have I should opt for a new one with higher operating pressures.

 

You have one of two possibilities happening. Either the air governor is sending signal pressure to the air dryer purge port for an extended period or the purge valve on the dryer is not as fast acting as it should be. You will often hear a hiss from the air dryer purge valve after it purges. This will be your 20 psi air loss.

Run the truck at high idle. Pump your brakes to drop system pressure and start compressor. Go back to air dryer and listen closely when it purges. Is the purge short and crisp? Do you hear hissing before it fully seats and the purge stops?

 

If after the compressor cuts out and the dryer purges, the purge valve on the dyer, could be leaking 10%, or most likely the unloaders in the compressor itself are leaking. To test the unloaders remove the air intake from the compressor, run till the compressor cuts out shut it off and feel for any air leaking out the intake if there is, it is the unloaders. Personally I have an adapter, and use shop air to test the system it also could be the hose from the air dryer to the govenor.
Raising the preasure to 135 is normal, you loosen the nut and back out the screw, it is opposite to what you would think.

 

My problem is identical to this. I haul loads in excess of 80,000lbs and my suspension bottoms out just the same. I changed the leveler valve, dump valve, leaking air bag but its still not getting my suspension in a comfortable place when the truck is loaded.

I know this is years late but Texas_incognito did you find a solution to this?

Anyone, i am open to suggestions

thanks

 

Maybe you need more air tanks. If you double the volume of air you keep on reserve, the compressor won't be starting and stopping as much. Usually on 13 axle set ups thats the first thing that needs to be done if the truck was built as a 5 axle.

 

I did as was mentioned above, adjusted the governor to cut out about 133. Before that, and especially in the winter (when it's cold, rubber seals shrink and air leaks more readily than in summer) I had the same scenario, compressor cuts out at 120 and before you know it you're back down at 95-100. I pull a super b so, lots of maxi pots and bags to keep aired up. It works a lot better now. As far as your suspension "bottoming out" that one puzzles me. Are you loading heavier than normal 34,000 lbs on your drives? Even if you are, the bags should automatically air up to take up the extra load. What pressure does your suspension run at. On my WS 72 lbs is very close on a full load scenario. It never bottoms out. I read an earlier post where the guy said his suspension was at the same pressure as his air system. Thats bizzare. I'm surprised he wasn't blowing air bags. I think maybe his suspension gauge was plumbed in wrong? Just some ideas for you to think about.

 

Oh, I forgot. Put a high volume air compressor on. That with double the tank size should fix your issue.