| Author |
 Topic  |
|
|
Thomas Ford 85-16
Top Member
USA
4177 Posts |
 Posted - 01/11/2003 : 2:03:55 PM
|
The "spitters," as my bus's previous mechanic called them, have been going off spitting out the air at around 120 PSI like their supposed to but they will not stop doing that. Is it just trying to get out any moisture that may be in the tank or is there something wrong? I'll post a picture of what I'm talking about.
Stop at: http://buses.thesummit.biz
This is an industry where people brag about their times for 60-0, not 0-60.
Edited by - The BusBoy on 01/11/2003 2:09:59 PM
Edited by - The BusBoy on 01/11/2003 2:12:41 PM |
|
|
kd4jfd
Top Member
USA
1168 Posts |
Posted - 01/11/2003 : 3:34:38 PM
|
Check out your air compressor cutoff switch/overpressure sensor. If the compressor isn't shutting off when it should, your bleeder valve will try to let off the excess pressure, and this may be what you are hearing.
349 - A repair work in progress! |
 |
|
|
wagonmaster
Top Member
USA
2298 Posts |
Posted - 01/12/2003 : 05:50:07 AM
|
The air governor limits the amount of pressure that a given compresor will build. It can be adjusted. The "spitter" valve is trying to eliminate moisture from the air system by "spitting" what accumulates a the bottom of the air tank, where it is located. When working properly it will "spit" every so often. If it is doing that all the time, then it needs repair, tell you shop foreman. Hope this helps.
Joe
|
|
|
|
Thomas Ford 85-16
Top Member
USA
4177 Posts |
Posted - 01/12/2003 : 06:47:58 AM
|
Thank you very much for your answers. Where exactly would I find these sensors or governors? On the air compressor? These only started acting up this winter so perhaps the sensor or governor had frozen or something.
Stop at: http://buses.thesummit.biz
This is an industry where people brag about their times for 60-0, not 0-60. |
|
|
|
wagonmaster
Top Member
USA
2298 Posts |
Posted - 01/12/2003 : 7:59:49 PM
|
The Air Governor is located on the air compressor. It is generally gray in color and is cylindrical, about 5 inches long with a black rubber boot on one end to cover the adjuster. Like they say on TV, "Don't try this at home!" Take it to your shop and let the mechanics have a look.
Joe
|
|
|
|
bbird66
Top Member
USA
881 Posts |
Posted - 01/13/2003 : 12:43:43 PM
|
You may have a leak somewhere in the system also! It may not be large but the compressor maybe trying to keep up, better listen for one.
|
|
|
|
Thomas Ford 85-16
Top Member
USA
4177 Posts |
Posted - 01/13/2003 : 2:12:56 PM
|
Thanks again. I would take it to my mechanics if I had one. You have to keep in mind that some people own their own buses that tax payer money won't pay for since they have nothing to do with the districts.  As for the leak idea, I may replace my parking brake valve because if it's not turned right it'll leak slightly so it could be a problem.
Stop at: http://buses.thesummit.biz
This is an industry where people brag about their times for 60-0, not 0-60. |
|
|
|
peil
Active Member
USA
34 Posts |
Posted - 01/13/2003 : 10:00:24 PM
|
I have had troubles with these spitters two, especially in the winter. My spitters "spit" when the governor both engages and disengages,normal 90psi and 120 psi. The problem I had was when the bus was parked, air pressure would drain down, and the spitter would free open so that when you started the bus air pressure would not build until the compressor air started to warm and the electric heater in the spitter warmed it enough to thaw it out. I also had one spitter develop an air leak in the mechanism part of it connected to the line from the governor, which caused excessive cycling of the compressor. From your picture I feel there is a good chance we both have the same type of spitter. My feelings are that they are not worth the hassle. Give me a good air dryer and a manual valve on the bottom of the wet tank.
David Peil |
|
|
|
peil
Active Member
USA
34 Posts |
Posted - 01/13/2003 : 10:01:58 PM
|
I have had troubles with these spitters two, especially in the winter. My spitters "spit" when the governor both engages and disengages,normal 90psi and 120 psi. The problem I had was when the bus was parked, air pressure would drain down, and the spitter would free open so that when you started the bus air pressure would not build until the compressor air started to warm and the electric heater in the spitter warmed it enough to thaw it out. I also had one spitter develop an air leak in the mechanism part of it connected to the line from the governor, which caused excessive cycling of the compressor. From your picture I feel there is a good chance we both have the same type of spitter. My feelings are that they are not worth the hassle. Give me a good air dryer and a manual valve on the bottom of the wet tank.
David Peil |
|
|
|
Thomas Ford 85-16
Top Member
USA
4177 Posts |
Posted - 03/29/2003 : 8:33:40 PM
|
I was given a suggestion on how to diagnose whether it was a leak, compressor problem, or a problem with the spitters, and I wanted to run it by you all to see if it was safe.
First, I'd disconnect the spitters and build the bus up to pressure. When I got to 120 where they would normally go off correctly (but now continously go off) and see if the compressor stops correctly. If it did, then I'd know it's not a compessor problem. I would then shut down the engien knowing that the compressor has stopped and listen for leaks and see how well it holds the pressure. I'd then elminate that and determine the spitters themselves are at fault. Does that sound good and safe?
Stop at: http://buses.thesummit.biz
This is an industry where people brag about their times for 60-0, not 0-60. |
|
|
|
Wolf4dk
Senior Member
USA
74 Posts |
Posted - 03/30/2003 : 05:15:50 AM
|
hahahaha Spiters. Are you not talking about air dryers? heheh I never heard them called that before. But almost too funny.
If it was cold there, it is possible that it could have froze and done something to it. In that case, I would replace it.
Some busses require you to service the brake system. But I don't remember if you had to do that on these types...
|
|
|
|
Thomas Ford 85-16
Top Member
USA
4177 Posts |
Posted - 03/30/2003 : 06:25:46 AM
|
quote:
hahahaha Spiters. Are you not talking about air dryers? heheh I never heard them called that before. But almost too funny.
If it was cold there, it is possible that it could have froze and done something to it. In that case, I would replace it.
Some busses require you to service the brake system. But I don't remember if you had to do that on these types...
Well, that's what the previous mechanic called them. They literally do that...at 120 PSI they're supposed to let out some of the air, and you'll see a brief jet of vapor coming from beneath. I don't think freezing was an issue now because I started it up again in near 70 degree weather (30 right now, though. Welcome to Michigan.) and it still had the problem.
Stop at: http://buses.thesummit.biz
This is an industry where people brag about their times for 60-0, not 0-60. |
|
|
|
bbird66
Top Member
USA
881 Posts |
Posted - 03/30/2003 : 07:17:38 AM
|
If you see a jet of vapor coming out you better change the air dryer cartridge I'll bet that is loaded up with moisture and needs to be changed. I would also change the purge valve also (the spitter).When I had air I did that every two years regardless. You may have a little over 60$ between the two. I'm not sure what that dryer is, Bendix? Looks old.
God created only a few great mechanics....The rest repair cars. |
|
|
|
Thomas Ford 85-16
Top Member
USA
4177 Posts |
Posted - 03/30/2003 : 12:08:13 PM
|
quote:
I've had to write-up a few buses because the spitter was working overtime. Not suprisingly they were the older buses. But then I don't have to worry about it, thats what our mechanics get paid for.
Did you ever happen to find out what the problem was?
Stop at: http://buses.thesummit.biz
This is an industry where people brag about their times for 60-0, not 0-60. |
|
|
|
PHW
Top Member
USA
1345 Posts |
Posted - 04/02/2003 : 09:08:44 AM
|
Your spitter is actuated by a pulse of air from the air governor. The air line you see in your picture is from the air governor. When your air compressor reaches it's set 120lb max the air governor shoots a pulse of air to the unloaders in the air compressor which puts the air compressor into idle mode. This same pulse of air can be directed to other devices like your air dryers, spitters etc.
I would say if your spitter actuates at 120 but keeps on leaking afterward that would be your spitter problem.
PHW
Child Check For Life |
|
|
|
PHW
Top Member
USA
1345 Posts |
Posted - 04/02/2003 : 09:13:25 AM
|
I was just looking at your picture and couldn't help but notice your custom muffler straps.
PHW
Child Check For Life |
|
|
|
Thomas Ford 85-16
Top Member
USA
4177 Posts |
Posted - 04/02/2003 : 5:37:35 PM
|
quote:
I was just looking at your picture and couldn't help but notice your custom muffler straps.
PHW
Child Check For Life
I thought that was stock...
Stop at: http://buses.thesummit.biz
This is an industry where people brag about their times for 60-0, not 0-60. |
|
|
|
rswboe
Top Member
USA
675 Posts |
Posted - 04/04/2003 : 10:38:30 AM
|
Wow, don't any mechanics read these? Your "spitter" is probably the purge valve on the air dryer, unless you have an automatic drain valve on the wet tank (first air tank in the system). If the valve cycles constantly there may be a blockage in the air dryer, or a problem with the unloader valve in the compressor. This condition MUST be diagnosed by a professional. DO NOT mess with the air system unless you know what you are doing. 120 psi of better can cause bodily injury for starters, then there is the liability involved. Improper air system operation may result in a general failure of the brake system. Do you think the taxpayers will pay for the funerals if you screw this up? If you can't afford to fix the bus, sell it.
|
|
|
|
PHW
Top Member
USA
1345 Posts |
Posted - 04/04/2003 : 11:17:19 AM
|
Wow, Sounds like your hitting about 212 degrees.
PHW
Child Check For Life |
|
|
|
Thomas Ford 85-16
Top Member
USA
4177 Posts |
Posted - 04/07/2003 : 10:41:59 AM
|
The system seems to be a combination of what many of you described here. There's what appears to be the control vavle on the front of the wet tank of the system. From that vavle, a small air line runs to each of the vavles that I have pictured, which according to PHW, is probably the thing that sends a pulse of air. Am I correct? About the whole taxpayer thing it seems many people here fail to realize that it's indeed possible to have a privately owned bus for personal use and have a low income... Plus, it's not like too much can go wrong when you have all the shop manuals telling you how to clean the vavles in the first place. They lack descriptions of troubleshooting and such, which is why I came here. And I think most people would to air system repairs with it mostly empty....if not, it would probably be for something very specialized.
Stop at: http://buses.thesummit.biz
This is an industry where people brag about their times for 60-0, not 0-60. |
|
|
|
rswboe
Top Member
USA
675 Posts |
Posted - 04/09/2003 : 09:51:45 AM
|
Close PHW, about 210, gets that way some days. Having worked for a general repair shop for about 20 years befor going into the public sector, I've seen some single vehicle operators (not just buses) do some pretty strange (and frightening) things. Just a little touchy I guess.
|
|
|
|
PHW
Top Member
USA
1345 Posts |
Posted - 04/09/2003 : 10:35:51 AM
|
rswboe,
Good to hear your keeping your cool. These posts are interesting for kicking things around. Your point well taken tho on the hazards to people unaware of risk areas. Note that wagonmaster always qualifies his answers where appropriate "don't do this at home but take it to your mechanic".
What's really scary is seeing so called mechanics doing some "pretty strange and frightening things".
Will the real mechanics stand up.
PHW
Child Check For Life |
|
|
|
Craig Thoricht
Senior Member
USA
177 Posts |
Posted - 04/10/2003 : 03:56:25 AM
|
Hello-
As a "Real Mechanic" I feel that IMHO there is and always will be a huge communication gap between mechanics and drivers. Many times we BOTH don't understand why the other did what they did. We are all human!!
I also need to point out that school buses are a very different animal as far as machinery is concerned. I have been a professional mechanic for 34 years in several areas but I must say that I enjoy working on buses. I learn something new almost every day but I am baffled about how the manufacturers approach building this equipment.
Another wild card is the that the wrong people are writing specifications for the wrong reasons.
Case in point are these "spitter" valves discussed in this topic. These are not meant to take the place of an air dryer, but someone had this bus built this way and now it's not doing it's job. What a surprise.
How do you get away with those muffler hangers? I showed that picture to my Ohio Highway Patrol bus inspectors and they were not impressed.
One final thought- the safest form of transportation ON EARTH is inside a yellow school bus. This is the result of a lot of people working together toward a common goal. Drivers, mechanics, supervisors and school administrators. We don't want to lose sight of that goal.
Craig Thoricht
|
|
|
|
PHW
Top Member
USA
1345 Posts |
Posted - 04/10/2003 : 07:30:58 AM
|
This is the safest transportation industry and we all should take great pride in that accomplishment.
When we notice items like the custom muffler straps we dont want to scare people off from posting due to the fear of being too critisized. I'm sure there are people who do not realize what alot of mechanical standards are. By bringing stuff to this forum they can be informed in a positive way while also enlightening many others who read these posts.
Keeping our industry the safest is a never ending process which I feel this forum is a great tool.
Keep it up guys. I'm enjoying these great posts. Just a personal opinion.
PHW
Child Check For Life |
|
|
|
rswboe
Top Member
USA
675 Posts |
Posted - 04/10/2003 : 10:24:54 AM
|
10-4 on the mechanics' doing some strange and frightening things, no one is immune (I've pulled a few myself). Quite often it's from people who know better too, it's hard not to get complacent. I generally try to stay focused on what's important. My most critical issues are vehicle safety and garage safety. It's too easy to take short cuts and get hurt.
I don't want to scare anyone off from asking questions, especially in regards to vehicle systems, (the only stupid question is the one you didn't ask), I was trying to impress the importance of timely, proffessional repairs to safety-critical systems. The photo wasn't up when I posted my initial response, he'd be better off replacing the auto drain valve with a lanyard type. (Those chains are pretty funky, they might sneak past DOT, but they'd never get by State inspection here!)
|
|
|
|
MechanicMike
Active Member
USA
13 Posts |
Posted - 04/10/2003 : 12:29:33 PM
|
Spitters are awful, the original owner had to be in a tight cash spot. But anyway I agree with what my fellow mechanics said. Schoolies are great vehicles to work on I love my job very much and am proud to keep them rolling safely.
What was the worst mistake any of you mechanics made? Mine was putting gas in a diesel bus. probably the cardinal sin. But, we got it pumped out. Funny because the two buses were identical except for one was gas and one was diesel.
Mike Johnson: Chief Mechanic of the Kane, PA Central School District. |
|
|
|
Thomas Ford 85-16
Top Member
USA
4177 Posts |
Posted - 04/10/2003 : 5:23:57 PM
|
My goodness, are chains taht bad? They came with the bus, so it means it's passed for it's 17 years of existence with those chains. They're not loose as you might think, they're very tight like any muffler straps should be. After it was mentioned on here and when I was searching for the control valve, I wiggled them a bit but I could not get them to budge...I think if that's the case, then it should be perfectly safe. As far as I know, all the other buses like it had the same system. As for the spitters again, I thank you for yuor help and hope to get the valve cleaned out this weekend if that's the case. I've been working closely via emails with the former mechanic a lot. He's given me the same warnings as you guys...the simple, common sense cautions.
Stop at: http://buses.thesummit.biz
This is an industry where people brag about their times for 60-0, not 0-60. |
|
|
|
PHW
Top Member
USA
1345 Posts |
Posted - 04/11/2003 : 07:11:38 AM
|
If those chains are OEM and meet federal standards you may have a point. What bus brand is this? Knowing from experience with our CHP department they would not pass these chains stating there not OEM or meet federal standards. Our CHP would probably require a written letter from the mfg. stating they meet federal requirements.
Most interesting.
PHW
Child Check For Life |
|
|
|
Thomas Ford 85-16
Top Member
USA
4177 Posts |
Posted - 04/11/2003 : 2:26:15 PM
|
quote:
If those chains are OEM and meet federal standards you may have a point. What bus brand is this? Knowing from experience with our CHP department they would not pass these chains stating there not OEM or meet federal standards. Our CHP would probably require a written letter from the mfg. stating they meet federal requirements.
Most interesting.
PHW
Child Check For Life
1985 Thomas Ford Conventional.
Stop at: http://buses.thesummit.biz
This is an industry where people brag about their times for 60-0, not 0-60. |
|
|
|
PHW
Top Member
USA
1345 Posts |
Posted - 04/15/2003 : 08:23:25 AM
|
I've never seen a Thomas product come original with the muffler secured by chains. Has anybody seen this from Thomas?
PHW
Child Check For Life |
|
|
|
Thomas Ford 85-16
Top Member
USA
4177 Posts |
Posted - 04/15/2003 : 4:37:43 PM
|
I know you guys told me not to fiddle with the governor, but you should be glad I did! I turned it a fourth turn at a time until I heard the spitters stopped messing up. I did, and going back in the bus, I found I had adjusted it almost exactly to 120 PSI. It's running great now, as far as I can tell, so I thank you all very much!!! And about the chains, they look pretty original to me. I sure didn't put them on, and there haven't been many changes to the bus and it hasn't failed. They're very secure, so I don't know why there'd be a problem in the first place.
Stop at: http://buses.thesummit.biz
This is an industry where people brag about their times for 60-0, not 0-60. |
|
|
| |
Topic |
|
Spitters
