MCI-9 No Air Up

[grantgoold]

Folks, today I visited the bus and as normal fired her up to keep things "fresh".  She started fine, but then noticed she wasn't building any air pressure.  No odd sounds. I do hear what sounds like almost a spuddering sound coming from the front of the bus around the spare tire compartment.  Sounds like a little air might be escaping from that location. 

Any thoughts on where I might start or steps to begin checking for the culprit.  I cannot shut down the bus as well and have to manually close her down. 

Thanks in advance for your ideas and help.

Grant

[luvrbus]

That sounds like the air dryer purge valve has a problem why MCI stuck the dryer there is beyond me but they under the spare tire compartment

[grantgoold]

Ok, that will be the first thing I check!

Thanks

Grant

[ol713]

   Hi;
      Might also try using shop air to air up the bus.  It would be easier to
      find an air leak without the noise of the motor running.
                                        Good luck,   Merle.

[Dave5Cs]

Grant yep your air dyer is on the front wall of the font axle well. Big long round thing. On the bottom is the purge valve Clifford is talking about. You can clean it out and make sure to drain all your tanks. There is water sitting in there somewhere. There purge valve can be unscrewed at the bottom but also sounds like your descant might need changing if it hasn't been ever. You can get rebuild kits at NAPA on Northgate Blvd. Talk to Bill during the week in the back heavy truck area.
HTH Dave5Cs

[luvrbus]

Does the MCI 9 use the old AD-2 dryer or the AD-9 ? the AD-2 is the pits to service in that small space when you change the descant,that big snap ring will eat you if not careful 

[thomasinnv]

Does the MCI 9 use the old AD-2 dryer or the AD-9 ? the AD-2 is the pits to service in that small space when you change the descant,that big snap ring will eat you if not careful 

I would assume an AD9. My mc8 had the AD9. I believe the 8's could have either one according to the maintenance manual. Just an assumption on my part though.

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[gumpy]

Couple things to try. Give the brake pedal a couple taps. Sometimes the valve sticks and can leak.  If you have air locks on baggage doors, the push pull button will often leak enough to prevent air up. Pull it out, or if you have enough air, push it in if it will hold. Air wipers also can leak enough to limit air up. Turn the valves a couple times. And finally, the governor can stick. Tap it with a plastic screwdriver handle to get it to free up. 

Otherwise, put some shop air in it and listen for leaks and spray soapy water. One air back or brake line failure can prevent it from building pressure.

[scanzel]

Check for mice eating through an air line. Twice I couldn't air up and once couldn't release parking brake because mice had chewed through two small air lines, could hear air leaking when bus was shut down. So far have trapped 12 mice since fall. Once they leave a scent the others come.

[Oonrahnjay]

Check for mice eating through an air line. Twice I couldn't air up and once couldn't release parking brake because mice had chewed through two small air lines, could hear air leaking when bus was shut down. So far have trapped 12 mice since fall. Once they leave a scent the others come. 

    I had a similar problem   I didn't believe the "if they get in, they attract others" but they did.  Then the storage place owner got a cat with a "cat flap" door into his area next door.  The cat can't get into my space but no more mice.  (I also got real careful about what food got left out and where.)