Absolutely no air pressure :0

[Muchee]

Hey Skoolie folks!

I routinely started by bus and noticed the air gauge isn’t showing any pressure. When I pull the silver knob for releasing the brakes it doesn’t do anything. I opened the unloader value and they looked clean and slid easily. Drained the tanks and no water came out. I live in stupid hot/humid Georgia.

Why am I not getting air pressurized?

 

[turf]

you're going to have to crawl underneath and do some troubleshooting. see if you can find air leaking. see if you can determine if you are making air and not storing it, or not making air at all.

if you're not making air... look at troubleshooting the compressor, if you are making air, look at the tank system parts. like an air governor.

good luck

 

[Muchee]

Hi

Thank you so much for you’re speedy reply!
Silly question but how do I know if I’m making air? Does the air compressor kick on and off like a household air compressor?

Could these things really go bad from not even using them? I parked here a few months ago and every month I start the bus. I haven’t broken or dislodged anything. So do compressors and governors just decide to crap out whenever they like?

Thanks

 

[sportyrick]

Fill out your personal info so we know what kind of bus and engine you have. Is the air compressor belt drive or driven by gears from the front drive?

 

[Muchee]

I’m sorry, I’m not sure how the air compressor is run.

1997 International M
FE Bus Genesis
3000 Series 30 Amtram
6 Cylinder
DT466

 

[turf]

sorry, but i don't know too much about air brakes. i like threads like this because i learn from others.

i assume the compressor is always on and making air. i think the tank system takes that constant volume and moves it where it needs to go, be it in a tank or vented out.

bendix has some real good troubleshooting flow charts for air brake systems.

i've replaced both a compressor and a air governor, and you want the problem to be the governor.

you're going to have to look for air leaks while the engine runs to start your diagnosis.

did your low air alarm let you know the system failed or is it not working?

mice, vandalizm, old age lines, dirty fittings, broken belt......who knows why they break.

good luck!

 

[Muchee]

Hi Turf!

Thanks for joining in Me too, I’m not super knowledgeable but enjoy learning and being independent! That’s awesome that you’ve had the chance to replace a compressor and governor. You prob don’t think that tho haha.

I wasn’t sure it’s a leak since it won’t even build. If it was a leak it would build then quickly go down right?

My brake light is on and usually goes off when it’s reached it’s psi.

I want to say it neither and just use my trusty hammer and do a magical tap on the dryer purge valve.

 

[ewo1]

I’m sorry, I’m not sure how the air compressor is run.

1997 International M
FE Bus Genesis
3000 Series 30 Amtram
6 Cylinder
DT466

You want to learn about brakes…?

Check here—> https://www.skoolie.net/forums/f37/amtran-service-manual-brakes-39364.html

 

[Muchee]

Damn ewo1! You’ve struck! Thank you for sharing all of these amazing resources. Please no one ever take this down. I will download as soon as I get my computer up.

 

[cadillackid]

compressor in that bus should be a gear driven Tu-Flo 550 with the serviceable unloader.. the D2 governers on the side are somewhat notorious for going bad..



the first thing i do is unscrew the big fitting at the top of the compressor, run the engine and try to put my thumb over the remaining fitting on the compressor and see if it quickly pushes my thumb off.. if it does then i know my issue is not within the compressor or the governer..

 

[miles_3m]

I will download as soon as I get my computer up.

Same! Thanks

 

[turf]

maybe a different way to check things out.....

if you have air available to you... try airing up the bus system from your compressor. sometimes there is a schrader valve on a tank that you can use to air the system up in an emergency.

that way you can see (or hear) leaks without running the engine.

you may need to chock the tires. playing with air underneath is a bad time to find out your bus rolls.

 

[somewhereinusa]

As cadillackid said check for air at compressor. Most likely it's the air governor, they are prone to failure, cheap and easy to replace. I used to carry a spare for my semi.

 

[Muchee]

Replaced governor

Hi guys,

I replaced the air governor and check the compressor. Still no air coming out of the that line on the top of the compressor. Does that mean that now I have to replace the compressor? Say it ain’t so.

Thanks!

 

[mmoore6856]

ok first if a govenor goes bad all you have to do is loosen it up and then see if it builds air as air govenors shut the compressor off. air preassure from the govenor when you get to 125 psi opens a port that feeds into the hole between the 2 mount bolts and opens the unloader valve (the intake valve for the compressor) so the compressor no longer creates any pressure. im not sure what you are referring to when you said unloader valve as its not visible unless you take the cover off. compressors do not fail that quickly unless there is catastrophic failure like a drive coupler exploding or a rod breaking. if you remove the govenor and it dont pump then your unloader valve in the compressor head is stuck open, you hooked the hoses wrong or put the 1/8 in plugs in the wrong holes of the new govenor.

 

[nikitis]

Since we're on the topic of Air.

I installed two new front air service chambers on my bus. Since then, I've noticed one set of air lines seem to lag behind the others. They both fill up, just one set is slower than it was before. When pressurized, I got out and checked the lines by the wheel and it's definitely not leaking. (Soap test).

And this only happened when I changed the chambers. Granted the original chambers were shot to ****, and the plunger wasn't even holding a seal. I could just push them in and out. but still built pressure better for some reason.

I didn't check the lines behind the gauge cluster though and I did unscrew those when I worked on my gauge cluster repair. I wonder if that could be it?



Also on another note. I want to add an oldschool WigWag for the air pressure, and since I have a front and back set of lines, the WigWag only seems to have one input, How did old rigs do this? Did they only have one air channel for all 4 brakes? Mine seems to have 2 channels, 2 brakes per channel.

 

[mmoore6856]

Since we're on the topic of Air.

I installed two new front air service chambers on my bus. Since then, I've noticed one set of air lines seem to lag behind the others. They both fill up, just one set is slower than it was before. When pressurized, I got out and checked the lines by the wheel and it's definitely not leaking. (Soap test).

And this only happened when I changed the chambers. Granted the original chambers were shot to ****, and the plunger wasn't even holding a seal. I could just push them in and out. but still built pressure better for some reason.

I didn't check the lines behind the gauge cluster though and I did unscrew those when I worked on my gauge cluster repair. I wonder if that could be it?




one brake slow to release is usually caused by mechanical friction. whenyou cut the end of the rod did you cut it to the bus specs? cant trust that if it was replaced earlier it was done correct . make sure it dosent go over 90 degrees when applied






Also on another note. I want to add an oldschool WigWag for the air pressure, and since I have a front and back set of lines, the WigWag only seems to have one input, How did old rigs do this? Did they only have one air channel for all 4 brakes? Mine seems to have 2 channels, 2 brakes per channel.

wig wags are not hooked to brakes as dot rule wont allow anything to be added to brake lines. wigwags are plumbed to the primary tank not the secondary or wet tank. thats why it only has 1 port

 

[mmoore6856]

some of you people scare me.

 

[nikitis]

some of you people scare me.

What part scares you the most?

I'll run a T splitter on my primary tank then when I install my WigWag.

And there's no way it's against DOT regulations. They still exist on rigs, and they are still sold. And people who are deaf and drive rigs need the visual indicator.

 

[cadillackid]

"cutting the rod" isnt the solution.. there is a clear procedure to setting the slack adjusters... you may beed to cut the rod (in fact on a bus you almost always do) but getting it right is following the correct slack adjuster set procedure.. even automatics need to be installed and set correctly..



theres plenty of bendix docs out therew for the googling to set it up the right way...