1980 Eagle Air Problem

ttrstudios · October 16, 2014, 08:13:20 AM

Hello All. I am a new bus owner. Just purchased a 1980 Silver Eagle Model 10 bus from a church in OK. I have searched and searched online as well as here as to what to look for when buying a bus to convert. I thought I did my homework. The bus looked and drove great! However I knew there were a few things I was looking at that needed to be fixed before actually getting the bus home which was a 7 hour trip to SW Arkansas. So I took it to a shop to have the obviously leaking wheel seal replaced. Had them change the brakes and a spring kit as well. I told the I would pick it back up the next day. Now, let me back up 2 hours. I drove this bus and was watching everything like a hawk! Oil pressure was GREAT! Air pressure up and down a little from 120PSI. Not bad. Long story short it made the 2 hour trip just fine. I go to pick it up the next day and now....

They told me that it wouldn't air up past 80psi after only changing the seal and brakes. So I got in it and bled the air off with the brake pedal. Watched it build back up to 75 to 80psi and stop. So we thought must be the govenor. Changed it and no change. We shut it down to listen for air leaks and there are not many at all. Now the funny part is this, The air dryer would pop off at 80psi before we changed the govenor and after I said well the gauge is wrong so changes that and it's the same thing. Sometimes the brakes will release but most of the time they wont because as soon as you release the brakes and push the pedal, the buzzer goes off indicating low air. I am lost! I thought the govenor is what "told" the dryer when to pop off? I have searched this forum over and found a few things that were a close relation but not identical. Anyway, I have a few questions please if you dont mind helping me out as the bus is stuck in Fort Smith Ar and I live 5hrs South.

1. What am I missing?

2. How many air tanks are on the bus as I have only found 3?

3. If the compressor is bad would it build up to 80psi?

4. Does anyone want to buy a bus? Just kidding. Please help!

Craig

eagle19952 · October 16, 2014, 08:20:27 AM

seems lately most of these problems are air dryer related, do you have one, is it in the vicinity of the AC compressor bay on the curb side ?

ttrstudios · October 16, 2014, 08:23:33 AM

There is one on the Curb side.

ttrstudios · October 16, 2014, 08:25:30 AM

Nope! Sorry. It's on the drivers side.

eagle19952 · October 16, 2014, 09:47:30 AM

Quote from: ttrstudios on October 16, 2014, 08:25:30 AM
Nope! Sorry. It's on the drivers side.

Service it or temporarily bypass it...in the quest for diagnostic expedience....

eagle19952 · October 16, 2014, 10:16:14 AM

ps. when you manually drain the air tanks...what comes out...?

pss there are 5 tanks

ttrstudios · October 16, 2014, 10:43:17 AM

Water was the only thing to come out of the tanks that I found.
We did bypass the dryer and ended with the same result.

As far as there being 5 air tanks, I know of 3. One above the steering axle, one under the driver seat (outside) and one above the rear drive axle. Where are the other two?

mung · October 16, 2014, 10:46:05 AM

Have you verified the pressure using a separate gauge? Are you 100% sure they didn't mess with anything else? Seems very odd that you had good pressure until they changed parts out.

John316 · October 16, 2014, 10:54:18 AM

Sounds familiar. I speak from my experience with our MCI coach. The air gauge is read from the main brake application tank. However, the low air buzzer (on ours) is located on the accessory system tank.

When ours wouldn't air up, like you describe, it was a pressure protection valve. It would open at 80, and close below 80. Basically it made sure that if the pressure fell below 80, that the brakes would get all of the air. And when the pressure was working back up to 80, that the brake tanks would get air first.

So if it was me, I would start looking elsewhere. Eagle guys will help out, I am sure. However, I would look for a pressure protection valve somewhere.

Another thing. You are totally confident that the air compressor is working, correct? We had a situation that the unloaders were getting stuck. It would air up some, but not all the way, and sometimes the dryer would continually purge. Something else to poke at, but it doesn't sound like your problem.

Best of luck.

John

luvrbus · October 16, 2014, 11:11:26 AM

That is a dual air system 2 tanks at the rear and most have a wet tank mounted on the rear axle housing 1 up front for the front brakes and 1 auxiliary tank above the spare tire compartment for wipers and air horn.

You can see the pressure protection valve at the rear in the tank on the drivers side, sure sounds like the pressure protection valve is giving the problem there should be dual read gauge or 2 gauges so you can read both systems

Then again you are working on a Eagle no 2 alike especially on the 80 model 10 a lot of stuff was carried over from the 05

eagle19952 · October 16, 2014, 11:58:17 AM

Quote from: luvrbus on October 16, 2014, 11:11:26 AM
That is a dual air system 2 tanks at the rear and most have a wet tank mounted on the rear axle housing 1 up front for the front brakes and 1 auxiliary tank above the spare tire compartment for wipers and air horn.

You can see the pressure protection valve at the rear in the tank on the drivers side, sure sounds like the pressure protection valve is giving the problem there should be dual read gauge or 2 gauges so you can read both systems

Then again you are working on a Eagle no 2 alike especially on the 80 model 10 a lot of stuff was carried over from the 05

Typically according to my "da book", there are between 4-5 check valves, it would appear, on the dual system dual air gauge, if both gauges are not passing 80 psi, well then it would seem that the main check valve is the culprit. It is located between the compressor and the wet tank a 3/4 inch pipe thread size.
additionally there are 1/2" ones located at the service reservoir, the park brake res. and one they call the outside service line, I assume the service brake line...?

and a 1/4 inch check valve at the park brake tank.
Things are not always as they appear... $:-\$

rusty · October 16, 2014, 12:36:19 PM

I would check the pressure relief valve. That bus might have one that is not part of the dryer. My 05 had that set up. A relief valve does not go bad that often but that is where I would start.

Wayne

Rick 74 MC-8 · October 16, 2014, 08:04:35 PM

Will it air with shop air?

Rick

ttrstudios · October 18, 2014, 11:40:13 AM

Thank you so much for all of the input. I'm sorry that I am replying late. Been working on the bus.

Well... We have not fixed the problem. It's working now. All we did was air it up with shop air and it's been working like it should. We've bled it down about 10-15 times and it's aired up on its on ever since. My guess is there was a piece of trash somewhere. Problem is it's still in there somewhere. So I'm sure this will happen again at some point.
So... We are going to try and make the 6hr trip home. We will see what happens. More to come on this adventure. The conversion will start as soon as it's home. Thanks everyone for the input.

akroyaleagle · October 18, 2014, 12:03:35 PM

I'm always amazed how much stuff gets fixed with the "stare at it" method!

Hope you make it home OK.

Everyone I know advises steer away from church buses. The bus seems like a good idea but no one ever ensures the maintenance is performed.

When you get it home, service everything. There is help here and the Silver Eagle Owners facebook page.

I doubt there is anything some one has not seen.