MCI air system

[artvonne]

  The 1975 MCI 5B I bought is not getting air to the air pressure gauge, warning light, wipers, or door lock, but apparently everywhere else. Ive been trying to find a manual or an air system schematic, and will contact MCI about manuals if I cant locate any anywhere else, but thats not going to help me today.

  Heres where im at. I put air into the accessory tank, the tank under the driver in the front left mechanical bay, and pressurised the system to approx 120 psi. The Bus aired up fully, the emergency brake valve released, the brakes apply and release, I have air to the various gizmos at the engine, belt tensioners and tensioner valves, etc., air at the ping tank schrader.

  However, when I flip the master switch to on, along with the other idiot lights that come on I get the low pressure warning light, the air pressure gauge in the dash panel isnt moving, the door air locking lock lever does nothing, and neither do the wiper controls, no hissing air, nothing at all.

  I found a MCI 9 manual online and looked at the air system schematic, but didnt see anything. I am wondering if there is some electric control valve that opens with the master switch on that allows air to reach the dash panel. Any ideas??

   

[buswarrior]

First, get the 3 manuals for the coach, Parts, Maintenance and Operators.

The air gauge is mechanical, so nothing fancy there.

Are you using the emergency fill or into the accessory tank directly? They are both under the driver.

All of the things you listed are fed from the aux tank, so I think you are connected to the other, so filling some of the brake system, the parking tank in particular.

If you want to fill the system in a more traditional manner, install fittings into the discharge muffler drain in the curb side engine access door, where it says "drain daily".

Did I mention get some manuals?

happy coaching!
buswarrior

[artvonne]

  Okay, I probably spoke too soon. Its looking like filling from the front aux tank im running into check valves upstream. Im going to leave the air alone and focus on getting the engine running, theres probably nothing wrong.

[thomasinnv]

you need to do like BW said and fill from the rear access door at the discharge muffler.  I believe by doing so the air will also go through the dryer (if you have one) so as not to introduce wet air to the system.

[artvonne]

you need to do like BW said and fill from the rear access door at the discharge muffler. 

  That is more than likely the case. I just spoke to a guy at a Bus shop. While he didnt have a book in front of him, between picking his brain and my own, I believe there are check valves down stream and im filling it from the wrong end.

 

[Fredward]

I've never tried filling my MC-5 from the front. But I fill it all the time from the back using shop air or on board air compressor. Works great. My 5A doesn't have a dryer,  but i installed an air fitting on the ping tank ahead of the wet tank. The gauge comes up, all accessories work and the brakes can be made to release. Its just like running the engine.
Fred

[artvonne]

  I know the brakes and suspension work, which were the main things I wanted to know about the air system, and now that I know I was filling it at the wrong end, I can remedy that if need be. But its time to go try and get her going, and thats tomorrow. Im heading out after I have breakfast. Got the trees along the driveway cut back and graded the bottom a bit, got a Coach net policy I hope I wont need, got to put belts back on the alternator, fix a hose, prime the fuel, and then....

  With some help from above I could be headed home Thursday or Friday. I really dont think I want to start out driving at night. Though im not sure why not if its running okay. Roads will be much quieter, cooler temps. We'll see.

[Busted Knuckle]

Sounds like you were just filling the front half (commonly referred to as the accessory side)
Filling it from the rear will solve all that.

Good luck and have fun.

Just remember that sometimes things go bump in the middle of the night !
  BK 

[buswarrior]

Don't go out at night unless ALL the lighting is working properly, or you are a BIG target for a pull over.

happy coaching!
buswarrior

[Busted Knuckle]

Don't go out at night unless ALL the lighting is working properly, or you are a BIG target for a pull over.

happy coaching!
buswarrior

BW we just ran the Vandy to Ft. Walton Beach run again this yr and all 3 coaches had all lights working when we left. But one had a taillight out, 1 had the top 3 center clearance lights out and one have the right rear clearance light out (we noticed all this while we loading!)

But one of the drivers said these kids have enough booze and "stuff to light" there shouldn't be any worries! LOL!
  BK 

[artvonne]

Good luck and have fun.

Just remember that sometimes things go bump in the middle of the night !
  BK 

 Fun? Thats the part im really looking forward to. The wife too. She is so tired of bouncing and yelling to be heard, the thought of something smoother and quieter has her excited to see it happen.

 Bump in the night? Its got a hitch that looked beefy enough, so ill be dragin the Jeep behind for spare wheels. The traffic around Little Rock has not been fun the few times I been down there, missing all that wouldnt bother me at all.

 Thanks again, BK, and everyone else, y'all been a lot of help.

[artvonne]

Don't go out at night unless ALL the lighting is working properly, or you are a BIG target for a pull over.

happy coaching!
buswarrior

  Copy that. I know one in the back was out, ill make sure I have em all burnin.

  And again, thanks a lot.

[artvonne]

  Just to follow up. I tried the schrader at the Ping tank, there is some blockage ill have to look at but it wouldnt take air. Just made a slow gurgling noise. I unhooked the drain line and screwed my air hose to that fitting, and that worked. This guys compressor is only building 90 PSI and I cant quite reach 90 on the guage, but low air warning light keeps flasing. Dash gauge works, wipers work, door lock is INOP. No major leaks, just a little hissing around the belt tension cylinders. All the lights work except one front inner clearance light, and the right side center roof clearance light. No emergency flashers, but turn signals work. Maybe just a flasher??

  I have a sprayer pump, tomorrow ill rig it and figure out how to prime it.

[bevans6]

There is a drain valve on the bottom of the ping tank, and the tank itself is just a hollow pipe.  Take the drain valve off and scrape out the congealed muck.  I replaced the schrader valve with a female quick-connect air fitting  and a shut-off valve, and I connect it to my air hose with a male-male adaptor.

Brian

[artvonne]

  Thanks for the great idea Brian, I'll have to try that. I think I'll blow down the air a few times through the drains to see if any gook or water comes out.