Air Governor Questions

[kiotiugly]

I noticed the other day that my truck, which is still very much new to me, seemed to have too much air pressure - the gauge in the cab was pegged out beyond 120 psi. I looked on the site and found the information for adjusting the air governor. I tried last night, and here's my questions:

1. Is the governor located on the firewall inside the engine compartment (maybe just to the passenger side of center)? I know this is a silly question, but if it is, the governor on my truck looks somewhat different than the one shown in the TM.

2. I tried to adjust the governor (if that is indeed what it is) as the manual indicated - loosen the jam nut, turn the screw (although on mine, it is another nut) and tighten the jam nut.

3. After doing the above, I started the truck and it run the PSI up to about 70 - so I re-adjusted and go the psi to level off at about 100-105. I thought that I had fixed the problem.

4. Then I started hearing a *POP*-shhhhh noise followed by a *click* about every thirty seconds. I checked at the governor (or whatever it is I adjusted) and that is where the air *POP*-shhhh is coming from - I can feel the air come out of it through the end, which has a little rubber cover over something that looks kind of like a grease fitting.

So here's the crux of this:

Did I indeed adjust the governor? Are there different types of governors?

Why is it making that air-dumping noise?

Is that noise okay or a sign of something bad? I never noticed that it made that noise before, but the gauge was always pegged out too. Maybe it just made it, but a lot more infrequently.

Thanks for all the help. Take care.

 

[gimpyrobb]

YUP, thats what it is and what it does. If it didn't "dump" the air, you would rupture something.

 

[kiotiugly]

Is it supposed to "dump" so often? That's my biggest concern, just because I haven't heard it before.

Thanks for the help.

 

[gimpyrobb]

I have yet to inspect one. (I like to take things apart) But mine does what you are describing.

 

[Hammer]

It will dump more often with the lower pressure.
Set the pressure to 120 psi. It should dump less often, and you will have maximum assist for braking.
Plus the extra reserve pressure if you have to use the brakes, or other air items, that often.

 

[tm america]

i want to adjust mine to its set at about 90 now.which way did you have to turn it to raise the pressure .115-120 would be great

 

[m16ty]

i want to adjust mine to its set at about 90 now.which way did you have to turn it to raise the pressure .115-120 would be great

You screw it in (clockwise) to raise the pressure. FWIW, the federal DOT requires the governor to build to 120psi and kick back in at 90psi on air brake trucks.

 

[gringeltaube]

kiotiugly, I know of at least 4 different governor versions used from the early 50s on.... (Attached pic)...... guess yours is the "D" version.

While the old Style "A" acts like an on-off switch and can be heard from inside with the engine running, all others are more or less progressively (and quietly) opening AND closing when reaching their set points.
For better ID, styles "A", "B" and "C" are Bendix-Westinghouse brand, "D" is made by Midland.
All are easily adjustable (just in a different way) for the desired range: closing at 90-100 and opening 110-120.
If working properly none of them should have air escaping at any moment from the breather or from under the rubber disc (arrow, 2nd pic) on style "D"!

Check yours for wear or dirt, eventually replace the whole unit.

G.

 

[kiotiugly]

Gringeltaube-

Thanks very much. It appears as though I do have the "D" version.

The air is escaping from the rubber disc (exactly as shown on your last pic). I don't think that it was doing this before.

Any idea on how to rectify this beyond just remove it, take it apart and clean it, and put it back on? Does anyone know a good souce for a Midland governor?

Thanks again for the help.

 

[gimpyrobb]

PM sent.

 

[dansautosales]

Does your air compressor run non stop or does it cycle in and out?

 

[gringeltaube]

................ Any idea on how to rectify this beyond just remove it, take it apart and clean it, and put it back on?
.....................................

You don't have to pull the whole unit to know what is wrong and eventually fix it!

See first pic: after removing part#s 1-3 get a 1 1/8" socket and un-screw plug #4. Remove piston #5 either with compressed air or pushing it out from the opposite side, after taking off plug #8 and screen #7.
2nd pic shows the critical areas to inspect for wear or imbedded particles. The face of the piston has a rubber insert which tends to get harder and slightly groved after so many years, making it difficult to seal against #4, especially at lower pressures, during the "open" (unloading) cycle. Most often it can be restored with some TLC, sanding and polishing... (That's what I will do with the one pictured, even if it was working properly!)
3rd pic shows the backside of the piston with its protruding rubber button. This keeps it sealed down inside the body during the "closed" cycle. Check the condition of both, button and seat, too.

Good luck!

G.

 

[kiotiugly]

Does your air compressor run non stop or does it cycle in and out?

How do I know if the compressor is running?

 

[frodobaggins]

How do I know if the compressor is running?

The engine is on...

 

[gimpyrobb]