| Author | Message | ||
| Nellie Wilson (Vivianellie)
Registered Member Username: Vivianellie Post Number: 428 Registered: 11-2008 Posted From: 74.4.48.228  Rating: N/A |
Hi Guys - Back again, and same old problem. I was sailing smooth, not a hitch and happy as a clam. Did Jack's Bussin' 10 (what a great rally!) and - on the way back to his place (for the BYOB thingy) - I stopped for some much needed fuel. Fired her up and... no air pressure. Had enough to safely move away from the pumps, but nothing (revving,tapping, banging, screaming, begging. cursing) would load the compressor. Oh, now and then the needle would rise a few pounds but it would always stop short of 'driveable' pressure. Jack, BK and Tom (White Eagle) came over to assist, but nothing worked. So we filled it with shop air in hopes of nursing it back to Jack's. Well, halfway there (here) it started making air again. Right up to 160 psi when we shut her down (bleeding it to 90 psi first). Since being here, she makes air every time we crank her up. And - like Jack says - how do you diagnose a problem when everything is working? So, consensus of opinion is: Got to be 1) the unloader valve or 2) the governor (and we all know how well I get along with governors  ). Current thinking is: Just replace both to be safe (and keep the "old" ones as spares). Any other thoughts? The governor is an easy switch (except in White River Junction) but changing the unloader requires some major surgery. So if there's something we're missing, I'd sure like to know before lighting the ol' blowtorch. Thanks much, Nellie Wilson | ||
| Dale Waller (Happycampersrus)
Registered Member Username: Happycampersrus Post Number: 359 Registered: 7-2005 Posted From: 166.225.8.49 Rating: N/A |
Change the governor first as I suspect that is the main culprit. White River Junction?? Oh no! (Just kidding, it's a nice place) My Mom's side of the family is from from Wilder. | ||
| ED Hackenbruch (Shadowman)
Registered Member Username: Shadowman Post Number: 225 Registered: 11-2003 Posted From: 75.211.68.129 Rating: N/A |
Nellie, i would go with changing the governor first too. About $20 for a new one. My 5A started acting up in Salt Lake City on our way north a few years ago. Wouldn't build air for a while, then it would, then it wouldn't. Had trouble with it in Boise, then Bend,OR. and finally got it to the DD shop in the Vancouver Wa. area where we got a new one. At one point i was going to have it towed to a shop. No problems since. My rule of thumb is when faced with more than one possible solution to a problem is to go with the cheapest/easiest/most likely solution first. And if it turns out that it is the last/hardest and most expensive solution that works, well at least you know that all of the other stuff is now done/new too and shouldn't give you any trouble for a while. :>) | ||
| Austin Scott Davis (Zimtok)
Registered Member Username: Zimtok Post Number: 395 Registered: 9-2006 Posted From: 209.156.24.114  Rating: N/A |
My vote is with the governor also... It is what "turns on" the compressor to pump air, and it sounds like that is not happening all the time. The valve may be getting stuck. . | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1784 Registered: 12-2000 Posted From: 76.71.102.113  Rating: N/A |
Just change the governor. Sometimes we know too much for our own good... A fresh governor is good preventive maintenance anyway. happy coaching! buswarrior | ||
| Mark Renner (Boomer)
Registered Member Username: Boomer Post Number: 186 Registered: 11-2006 Posted From: 75.211.195.169  Rating: N/A |
Sounds like the correct plan of action as above, but your governor should be set to unload at 120 psi not 160. Cut in: 90 Cut out: 120. Easy to adjust the governor, remove the rubber cap and turn the screw. | ||
| Patrick levenson (Zubzub)
Registered Member Username: Zubzub Post Number: 141 Registered: 5-2007 Posted From: 70.51.29.70  Rating: N/A |
not just the governor, but there should be a safety release in the air system that cuts in at some point. Cut in may be higher than 160 but 150 was more the standard on these old buses. Mine is on the rear tank, needs to be exercised once in awhile. Ya'll should work our why the the gov failed again, i.e. is your comp blowing lots of crud, or was it just a cheap gov. | ||
| Rob Norgren (Robsedona)
Registered Member Username: Robsedona Post Number: 210 Registered: 11-2007 Posted From: 71.118.24.14  Rating: N/A |
Did you not just change the Governor within the last 2 years??? | ||
| David Dulmage (Daved)
Registered Member Username: Daved Post Number: 273 Registered: 12-2003 Posted From: 142.46.199.30  Rating: N/A |
The purge valve on the air drier could be sticking. Sometimes they get rust or dirt stuck in the seat. | ||
| Tony LEE (T_lee)
Registered Member Username: T_lee Post Number: 69 Registered: 11-2007 Posted From: 59.154.42.140 Rating: N/A |
If the purge valve on the bottom of the dryer is sticking, you will hear air leaking from that point. Moot point now that the fault has gone away | ||
| larry currier (Larryc)
Registered Member Username: Larryc Post Number: 307 Registered: 2-2007 Posted From: 64.40.62.69 Rating: N/A |
Learn the sound of your compressor when it is pumping and note the difference when it cuts out. Sounds to me like the compressor was working fine and you are losing air somewhere. I'm not familiar with your airbags. Peterbilt and Kenworth air bags all rust out at the bottom overtime. As long as the bag stays on the lobe, everything is fine, the lobe seals the rusted out area of the airbag. Dump the suspension air and see if it airs the bags from the stops or if your problem comes back. | ||
| Jack Conrad (Jackconrad)
Registered Member Username: Jackconrad Post Number: 1197 Registered: 12-2000 Posted From: 74.4.48.228  Rating: N/A |
Nellie's MC-5 does not use rolling lobe airbags. They use double convolute air bags. We have determined that the problem is in the air compressor control circuit. When working the compressor pumps normally and we have air in the the line to the governor. This leaves the governor and/or the unloader as possible culprits. Unfortuanately the air intake cover over the unloader is almost up against the bottom of the floor making the installation of a rebuild kit extremely difficult if not impossible. Jack | ||
| ED Hackenbruch (Shadowman)
Registered Member Username: Shadowman Post Number: 230 Registered: 11-2003 Posted From: 75.209.72.87 Rating: N/A |
I am assuming that this means that you can't get to it thru the access panel in the floor in the back of the coach? | ||
| Jack Conrad (Jackconrad)
Registered Member Username: Jackconrad Post Number: 1198 Registered: 12-2000 Posted From: 74.4.48.228 Rating: N/A |
Correct, The air intake (unloader cover) is under the floor next to the access opening. The gusset in the passenger side rear corner of the access opening is over the front bolt on the air intake cover. The rest of the cover is under the floor and the upright bulkhead. Jack | ||
| Patrick levenson (Zubzub)
Registered Member Username: Zubzub Post Number: 142 Registered: 5-2007 Posted From: 70.51.29.70 Rating: N/A |
Is it easier to just pull the whole compressor (it is easy on mine but I have transverse engine the way it's supposed to be). In fact to get at my generator I have to pull the compressor. | ||
| ED Hackenbruch (Shadowman)
Registered Member Username: Shadowman Post Number: 231 Registered: 11-2003 Posted From: 75.209.72.87 Rating: N/A |
Been awhile since i have had mine open, those access panels don't really give you much access to anything,.....would have been nice if they had figured out a way to make them bigger. Hmmmmm, might have to take a closer look at mine next time and see if that is possible. Kinda have my doubts though. | ||
| Jack Conrad (Jackconrad)
Registered Member Username: Jackconrad Post Number: 1199 Registered: 12-2000 Posted From: 74.4.48.228 Rating: N/A |
Yes, a larger access panel would be great. but, I do not feel comfortable cutting on the framing to do that. And, I do not want to try to remove the unloader and not be able to get the new one installed. Not, that I mind Vivian staying in our yard, but I don't want to cause them to be stuck here when they have other places to be. Jack | ||
| clint hunter (Truthhunter)
Registered Member Username: Truthhunter Post Number: 599 Registered: 1-2009 Posted From: 24.129.233.51  Rating: N/A |
...reminds me of the the "old double walled hose internal collapse trick" (don't know if this is applicable on your setup)- the inner layer of a hose starts leaking and builds pressure traped between the layers, collapsing the inner layer and blocking air flow, intermittently. Some time after leak down, the blockage (or partial blockage) opens. Look & feel for bulging in the flexible lines next time this happens, if nothing is found, then perhaps proceed to "pinpoint pressure testing" starting right at the compressor to learn what is actually doing what & where. Even opening the fittings a few turns (as opposed to installing a test gauge, which means draining the system and temporarily fixing the blockaged you seek) might help with the diagnostics, -if you change the governor again, do a careful study on the old parts and try to figure out why it failed (crud, oil blow by). ~so then Vive when you get down to scollding the bus, is it in english or french or both ? might make a good back ground sound track for your next ballad (for those of us with "tourette ears"& "irish tounges") | ||
| Nellie Wilson (Vivianellie)
Registered Member Username: Vivianellie Post Number: 429 Registered: 11-2008 Posted From: 74.4.63.215 Rating: N/A |
My Dear Friend Clint - I curse and swear and scold equally well - and loud - in both languages. Which is to say, I'm much like our ex-prime minister: who was said to be functionally illiterate in BOTH official languages Thanks for the thought on hoses... might be something there? Hate to swap everything out and find out it's a stupid hose (though they look and feel solid). Turns out somebody already cut the framing to enlarge the access port... so taking some more out won't hurt a thing. Whatever support there was has been long gone anyway. Gotta just love these buses, don't you. Well, don't you???? Nellie | ||
| ED Hackenbruch (Shadowman)
Registered Member Username: Shadowman Post Number: 232 Registered: 11-2003 Posted From: 75.210.15.114 Rating: N/A |
I love mine, even when i hate it! :>) | ||
| clint hunter (Truthhunter)
Registered Member Username: Truthhunter Post Number: 600 Registered: 1-2009 Posted From: 24.129.233.51 Rating: N/A |
sure do !!!! you too !!!! |