How to get under Bus without air?

[lostagain]

Isn't alcohol bad for the dryer?

JC

[neoneddy]

Update on my similar situation, everything is airing up normally now.


Sent from my iPhone using Tapatalk

[Fredward]

Sometimes my MC-5 had what I assume to be a check valve that froze causing the pressure to build up too high; then the high pressure relief would release until pressure dropped back down then it would go through the same cycle repeatedly. Evidently the place that the governor monitored pressure was after that check valve so the governor never cycled the compressor because the pressure never made it past the frozen check valve. I would move the coach from the unheated side of my shed to the heated side. Once it sat for a few hours in the heated shop, the problem went away.

But it was a pretty loud discharge, not an air leak hiss. My vote would still be for something frozen although today's weather should clear that up. I'd vote for running the engine and compressor some more and maybe the relatively warmer compressed air from the compressor will solve the problem without climbing underneath. ??

Fred

[eagle19952]

When a compressor sees set pressure the governor tells it to go into unload mode. simply said, it holds the valves both open and the compressor swaps it's effort back and forth between both cylinders.

If the dryer is frozen, it will simulate this condition, except the dryer becomes the point and nothing beyond will get to set pressure.
Normally the dryer will "leak" at the dryer purge exhaust under this condition.

Have you tried airing the system with an auxiliary/shop/portable compressor upstream of the dryer?

bypassed the dryer with a fabricated hose ?

last, were i you i would take a sawzall or chain saw and cut the plastic blocks out and proceed.

[Fred Mc]

When it is too cold for my diesel tractor to start I take a small construction heater and direct it at the engine under a tarp.If you think this is cold related and something may be frozen  apply heat under the bus using some type of forced air heater to thaw things out. It it was a frozen pipe/tube I don't think it would leak past the frozrn section.And even if it was a rupture in a pipe I think the air compressor would have enough volume to evercome it.

Regards

Fred

[lvmci]

Neoneddy, there are 2 tanks behind the front wheels, in the middle, you pull the nipple or ring, to release these air tanks and moisture, I recently replaced both relief valves, lvmci...

[Scott & Heather]

Just a data point, I have in the past experienced a frozen purge valve so I understand and am familiar with that scenario. That’s not what I have going on here. Coach won’t build any more than 10psi. Air hisses loudly out of area between duals. I’m guessing the leak is in one of the short copper lines up in there. I just can’t seem to get the coach jacked high enough to get myself and blocking underneath. Of course I can’t release the brakes so I can’t pull it up onto wood ramps. I’m just stuck... at my wits end here. I’ll try running brake line antifreeze through the system but it’s 38 now here. I can’t believe anything is still frozen.


Sent from my iPhone using Tapatalk Pro

[neoneddy]

@scott:   at 38 that's only 6 degrees above freezing.   Everything that is frozen is under the bus, ambient air isn't going to melt anything quickly.  Yes the ambient temp is warm enough, but it takes a lot of heat to warm up that much  mass. 

When I first fired up my bus this morning it would not build anything.  Even with the home compressor running and the engine revving the needle just bounced a bit past 0.

I think the sea foam did the trick for me,  I added that to the fill nozzle and ran the home compressor some with the bus off.   Then I ran the engine for 1-2 minutes.    Let it rest for 5-10 ... then fired again and it came up to 30 psi right away.  Then the story picks up where I posted earlier with the leak up front.   I had hissing from almost everywhere it seemed.

I hope I'm not giving bad advice, just trying to help.  It worked for me today, we had that -25 stuff what? 36 -48 hours ago.   Feels balmy right now.

[Scott & Heather]

Ok I’ll give it a try....if it ends up being that easy, I’ll hug you hahah


Sent from my iPhone using Tapatalk Pro

[PP]

Scott, since you ruled out the air dryer, my blind monkey won't do you any good. But I wish you luck,
Will

[DoubleEagle]

If it's a leak from a valve not closing, the idea of using a kerosene heater with tarps around the bottom might work. Even though it is above freezing now, it was below freezing for a long time prior (all that metal mass will take time to warm up). If it is a break because of freezing or whatever, you will need to get under to repair. Try smaller scissors jacks or whatever short bottle jacks will fit to get the bus up a little to give you more room for a bigger jack. Is there someone close by with a larger forklift? Digging a hole might help. If the ground is frozen still, a hammer drill with chisel bits would dig it out. There might be higher points to jack from within the engine compartment.

[bobofthenorth]

My money is still on a stuck relay.  How about a cube heater pushed in between the duals?  And I'm a big fan of a judicious whack as a cure for a lot of situations.  Its frowned on as a cure for domestic difficulties but anything involving equipment I'm open to that as a potential cure.  Can you see the relay? Poke it with a stick?

[sledhead]

this might be low enough ( 6. 3 /4 " ) to get in there just get a longer handle or eat your wheaties

 https://www.harborfreight.com/12-ton-heavy-duty-low-profile-industrial-hydraulic-bottle-jack-66569.html

dave

[Geom]

Scott, maybe I'm missing something, but can you get a tall-enough jack under just-ahead of those blocks (but still under that radius arm) and lift up just enough to loosen the blocks and slide them out? I would think that you should be able to apply quite a bit of lifting force on that radius arm (you'd want to double check that of course), to get one side at a time to lift the two or three inches needed to get those blocks removed.
Once they're removed you can put your jack under the proper lift point and repeat on the other side.

[chessie4905]

Rent one of those kerosene space heaters and aim it under  bus in appropriate area. Keep it back enough not to get surface of coach too hot.