| Author | Message | ||
| H3-40 (Ace)
Registered Member Username: Ace Post Number: 901 Registered: 10-2004 Posted From: 75.200.209.209  Rating: N/A |
I posted this on the MAK board but thought I needed to share it here as well. Well today I put an Air Compressor in my bus. It all started when a friend of mine was on his way back home and his H model Prevost bus would not air up and lift off the tires. This would have left him stranded at the restaurant he was at or at least with a costly tow bill but, he had a portable air compressor in his bay. He simply plugged it up and hooked it to his bus air via a factory air chuck and his bus lifted up and away he went, all the way home with his portable air compressor running without any trouble. He then took it in the local shop to find he had a faulty valve (can't remember what it was exactly). He told he me was very glad he had the compressor in his bus and that got me to thinking, "Hey I have one, why not do the same thing"! So today was the day and it worked out great! I even installed my air hose reel next to the compressor for easy access to the hose. I also have enough hose to go completely around the bus to air tires if needed. This will also come in handy IF I ever need to air the bus early in the morning at a campground which is doubtful since I never want to leave early anyway, if at all! Another tip he gave me was to install a hose outlet where you connect a hose to access water. just in case you need water in the radiator (during emergency times of course) or to cool off a hot brake or tire. Using cpvc pipe originally, it was easy to splice in just off the shur-flow water pump with a hose connection and a valve. I have enough water hose to reach each corner and then some! Granted, everyone hopes we never need to use these for emergency but, it's better to have them IN the bus just in case than it is to say "I have them at home and WISH I had them now" on a dark Sunday night in the middle of nowhere! So with all this good information from my friend, I pass this on to you guy's. If you have a compressor your not using, put it in the bus. You just might need it to get home one day and if you can plumb in a water outlet, do it as it makes it very easy to acces water without using jugs or bottles! Ace PS Thanks Bill | ||
| RJ Long (Rjlong)
Registered Member Username: Rjlong Post Number: 1433 Registered: 12-2000 Posted From: 67.181.166.160  Rating: N/A |
Great suggestions, Ace!! Might I also add that fellow busnuts should check their coach's air system's schematics in the shop manual before plumbing in an air chuck for use with a portable system, unless the coach already has them. Reason I mention this is that many coaches have check valves in the system that only allows air to flow one way - usually from the air compressor thru the wet tank, dry tank(s) and finally to the accessory tank. Obviously, if you try to fill the system from the opposite direction, the check valves will not allow you to do so. If your coach already has the air chucks from the factory, like Ace's does, then this is a moot point. But for those with older models, take a few minutes to find out how your coach is plumbed. In my case, my 4106 actually has chucks both front and rear, so the system can be filled from either end of the vehicle. So do your homework before starting this simple project. Thanks for sharing, Ace! FWIW & HTH. . .  | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 563 Registered: 8-2006 Posted From: 74.33.46.157 Rating: N/A |
RJ,I want to be real clear on this you are allways talking about safety and now are you saying plug a 5cfm compressor or less into the bus air system and go? good luck (Message edited by luvrbus on October 29, 2008) | ||
| H3-40 (Ace)
Registered Member Username: Ace Post Number: 903 Registered: 10-2004 Posted From: 206.53.144.178 Rating: N/A |
I'm real curious as to where in this thread was 5cfm ever mentioned? Even on the MAK thread where it got carried away with the safety issue, I don't recall anyone mentioning using a 5cfm or less compressor! I think this is one way these post get miscontrued! Not sure what mine is but I will check tonight when I get home. I would think 5 or less is pretty small and cheap too! I will post my compressor specs later! Ace | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 565 Registered: 8-2006 Posted From: 74.33.46.157 Rating: N/A |
Ace,most of the 120v portable compressors are low in cfm.My 6 1/2 hp coleman in the shop is 8 or 12 cfm i got the 5 cfm from a dual tank Emglo that I have is 5 cfm. (Message edited by luvrbus on October 29, 2008) | ||
| H3-40 (Ace)
Registered Member Username: Ace Post Number: 904 Registered: 10-2004 Posted From: 206.53.144.101 Rating: N/A |
I'm not saying they aren't but wasn't sure where it was ever stated. Like I said I'm not sure what mine is but will check later! Ace | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 566 Registered: 8-2006 Posted From: 74.33.46.157 Rating: N/A |
Ace, was the kneeling valve his problem I know my on my H41 the parking brakes will not release if it is in the kneeling postion, but you could drive it with the buoy applied I drove it in some high winds by lowering it the 4 inches made a big difference in the AZ wind good luck (Message edited by luvrbus on October 29, 2008) | ||
| RJ Long (Rjlong)
Registered Member Username: Rjlong Post Number: 1434 Registered: 12-2000 Posted From: 67.181.166.160 Rating: N/A |
Luvrbus - Hmmmmmm. . . I just re-read my post, and I don't see anywhere in it where I said anything about moving the coach. I was simply suggesting busnuts study their coach's air schematics thoroughly if they want to install an air chuck to be able to air up the coach using some type of portable compressor (or shop air, for that matter), if their coach isn't already equipped with one from the factory. That's all. . . no more, no less. FWIW & HTH. . . | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1378 Registered: 12-2000 Posted From: 76.68.135.7  Rating: N/A |
I doubt any postings on a bus board for or against, will stop a fool or encourage a smart person, to do something stupid or unsafe. We already have a thread out of control with innuendo and unnecessary emotion elsewhere, let's keep it sensible on here, eh? happy coaching! buswarrior | ||
| Mel La Plante (Mel_4104)
Registered Member Username: Mel_4104 Post Number: 91 Registered: 7-2006 Posted From: 216.232.55.174 Rating: N/A |
to plumb in a extra port for an external air source go to your aux. tank and insert it there or in any out put line such as windshield wiper or horn line between the tank and the next fitting, this will not only fill the aux. tank but when the air presure in the aux reaches 60#the check valve in the main line from the engine compresor will open and back feed to the wet and other tanks. this check valve is in the system to shut of air to the aux should the engine compresor fail, it shuts of the air from the other tanks so that you have enough air in the wet tank and main tanks to make a safe stop. there is a one way valve coming out of the compresor that prevents air from bleeding back through a faulty compresor. how ever when the air in the aux. tank is depleated none of the air operated things such as air horn,wipers and others, however you will still have 60# of air in your braking system if you have not made a brake application. | ||
| Patrick levenson (Zubzub)
Registered Member Username: Zubzub Post Number: 28 Registered: 5-2007 Posted From: 70.53.183.70 Rating: N/A |
BTW I know it's not a good idea to drive with an aux compressor but if your bus has air spring brakes or dd3s pressumably it will stop if you don't have the air you need. Speaking as someone who has neither, I am very aware (terrified) of the air consumption of my braking system so I watch it very carefully. If I apply pressure progressively without backing off I use the least amount of air and decelerate quickly, that being said I would never drive without a functioning air compressor. | ||
| H3-40 (Ace)
Registered Member Username: Ace Post Number: 905 Registered: 10-2004 Posted From: 75.248.29.180 Rating: N/A |
Well I went and looked at my compressor, (my portable compressor) and sure enough the stat label is partially scraped off but I'm thinking it's somewhere around 3.5 cfm @ 90 psi. It's a 1hp 3 gal compressor and works just fine for my intentions. It may not be something some of you would want to do but hey, I feel better having aux air in the bus than I do in my shop, especially when I'm not at home! To answer your question about the kneeling valve? No it was not that! I think somewhere along the line, it got confused with what was the original problem. The valve was found only AFTER it was in the shop! The valve was not the reason for using the aux air. The broken air line was the reason! Ace | ||
| Tom Caffrey (Pvcces)
Registered Member Username: Pvcces Post Number: 1234 Registered: 5-2001 Posted From: 65.74.65.209 Rating: N/A |
Mel, I really can't speak for 4104s, but in the 4106, air will feed from the auxiliary to the main tank at very low pressure; this is a straight check valve. On the other hand, if you apply air to the main tank first, then the pressure will have to reach 60 to 65 pounds before admitting any to the auxiliary tank. I'm not sure of the right name for this valve, but I call it a minimum pressure valve. I think that this might be what is used as a tractor protection valve on a semi. As I understand it, after the pressure reaches 65 psi, air flows readily to the auxiliary tank. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher Ketchikan, Alaska | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 756 Registered: 11-2005 Posted From: 208.54.200.210 Rating: N/A |
I did the same as Mel. My aux tank already had a T and a valve so I installed a female air hose disconnect so I could use air tools or inflate tires. To fill the bus system from outside I made up a double ended male quick disconnect and plug that into the female quick connect, then plug in the outside air hose. | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1380 Registered: 12-2000 Posted From: 76.68.123.198 Rating: N/A |
The valve that prevents air into the accessories under low pressure is called a pressure protection valve. It protects the brake circuits from an air problem in the accessories by not letting air into the accessories below its set point. Adjustable by screwing the top in and out. A commonly failed valve in conversions and second/third tier bus companies, as it has not been maintained or checked. A big problem if one was to burst a suspension bellow, the air compressor would pump overboard, and whatever is in the brake circuits is all that would be available, provided the check valves were working....otherwise it all goes out... When working, the PPV would close, traditionally set, give or take, as the pressure drops past 70 lbs, allowing the compressor to maintain that lower setting in the brake tanks, giving the driver some choices as to what happened next. Keep in mind that the compressor will now be running non-stop, any excess air beyond the PPV setting being allowed through and out the hole, so this is still a get off the road to a safe refuge operating condition, but at least the driver has the option of moving and stopping. I'm wondering what the long term effects might be of blowing volumes of air backwards through the PPV when airing up via the accessories tank with an aux compressor? happy coaching! buswarrior | ||
| David Lower (Dave_l)
Registered Member Username: Dave_l Post Number: 89 Registered: 11-2007 Posted From: 67.58.201.10  Rating: N/A |
BW is this accessorie tank the one under the drivers floor that you access through the door to get at the steering box, because on mine there is a tire valve on the end of this tank and there is another tire valve in a "T" fitting above the alcohol jar just inside the passenger side engine door. Dave L | ||
| RJ Long (Rjlong)
Registered Member Username: Rjlong Post Number: 1435 Registered: 12-2000 Posted From: 67.181.166.160 Rating: N/A |
Tom - The minimum pressure valve, as you call it, is shown of page 2 of section 4 in the 4106 shop manual. Gotta study the page a minute or two to find it. BW - Haven't looked at an MCI air system schematic, but Tom's and my 4106 have a check valve on a separate line coming off the accessory tank that bypasses the pressure regulator valve (on the input side of this tank) to return air to the wet and dry tanks, should there be a sudden air loss on that side of the valve. So in our case (as with the 4104's also), no harm by filling from the front. Take a look at your MCI's schematic, and see if it's not similar. I suspect it probably is. FWIW & HTH. . . (Message edited by rjlong on October 31, 2008) | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 602 Registered: 8-2006 Posted From: 207.231.75.253 Rating: N/A |
Why not fill it from the back, with a tee in the compressor output line? Then air flows thru the drier, check valves, and protection valves, just as with the engine driven comp! This way you can air up dry and quiet in a campground, release DD3's or springs, and drive with a main comp failure, AND have dry aux air for whatever? George | ||
| RJ Long (Rjlong)
Registered Member Username: Rjlong Post Number: 1436 Registered: 12-2000 Posted From: 67.181.166.160 Rating: N/A |
George - Good point, well taken. In my case, as I mentioned before, my 4106 has air chucks both front and rear. . . At the transit property where I used to work, whenever one of the coaches had a road failure and had to be towed in, the shop hooked an air line into a chuck in the front of the coach, behind a panel between the headlights. I do not know if this line went all the way to the rear and was teed in there, or if it was teed into the aux tank. But it kept them from having to run a hose all the way to the rear. FWIW & HTH. . . | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 367 Registered: 7-2006 Posted From: 70.210.179.202 Rating: N/A |
George....tha is the way our coach is don...and for the reasons you stated. Just after the compressor, prior to the dryer....and where the tow company has attached a hose...twice...  FWIW RCB | ||
| Tom Caffrey (Pvcces)
Registered Member Username: Pvcces Post Number: 1235 Registered: 5-2001 Posted From: 65.74.65.209 Rating: N/A |
Will the air dryer work if there is no purge cycle? I don't know, but I've wondered just how effective it might be. In our case, I figured that any air use through the auxiliary tank would not amount to much, in the scheme of things, so I didn't worry very much about it. RJ, I found that valve years ago; that's how I knew about it. Ours leaks a little through the top. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher Ketchikan, Alaska Tom Caffrey PD4106-2576 | ||
| Dan West (Utahclaimjumper)
Registered Member Username: Utahclaimjumper Post Number: 118 Registered: 1-2005 Posted From: 208.66.38.115 Rating: N/A |
Tom, are you planning Quartzite this year?? when??>>>Dan | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 529 Registered: 10-2006 Posted From: 66.90.229.178 Rating: N/A |
I have heard of one bus being driven home with a crapped engine compressor b using a Buel (marine high quality DC compressor)for air horns. If you pre flight using the guide from RJ , you see a decent system needs very little air to function . If you have a tight coach air system , a remarkably small air supply will work fine. FF |