bus not level when air up

[buswarrior]

Sheesh...

bowmaga, if you're still here...

using your mainteance manual pictures, determine if the arms for your leveling valves are there, connected, bent, missing, etc. flashlight is a handy tool. Never mind the compex, deal with the simple first.

As for your safety... as long as you aren't touching anything, see directions below.  The danger with air suspension and novices, is you mess with the airlines or height controls or anything else you have no clue about and lower the bus onto yourself... you won't be doing that without further preparations, more height, blocking the suspension blah blah blah, will you?

Car grade jacks and ramps and jack stands are NO MATCH for your bus, they are too weak to protect you.

ok, got some 2x4 2x6 2x8 whatever lumber lying around? Run the rear wheels up on a collection of 2x lumber, be sure to mix and match the direction of the pieces and stack the collection tightly to make a secure footing. You'll need enough to make a couple of steps for the tires to climb. You ony need enough layers to fix it so the bus body, at it's lowest potential travel, can't squeeze the life out of you if it comes down. Also makes it easier for the full figured boy to crawl around a little more graciously...

Report back on your investigations.

I'm pulling for you!

happy coaching!
buswarrior

[skipn]

Greg,

    So where are things at now?

Skip

[bowmaga]

not much farther...but I'm not still laying underneath the bus either.  I didn't get a chance to really dig into her. She still won't level up and the tag won't drop.  I did find back by the tag axle valves, there is a solenoid on each line.  One of the solenoids wires are broken and not connected and i can seem to see where it would go.  Could this be a part of my problem.  I will take some pictures tonight of what it looks like and post them.  It took until sunday afternoon until she completely lost her air and is all the way down on both sides.  Also, i know the previous owner had to replace one of the air bags.  I do not know which one it was or which side.  He won't answer my calls or return my emails.  I have the hunch that has something to do with it also.  I forgot all about that until I was in her yesterday and saw the old air bag laying inside.  I'm a little lucky, in the aspect, that I work for a construction company and, at my shop, we have a pit in our mechanics bay, and its big enogh to get this big girl in.  Though my mechanic has never worked on MCI bus, he has worked on numerous tri-axle dump trucks and semi's, and made me feel a lot better after talkking to him this morning.  He's going to take a look at it with me one of the next few weekends, and see if we can figure something out.  Until then, I'm going to try to work on the tags, myslelf,  to get them to move.  I assume lack of grease, is part of the problem.  And then start gutting it and working on other stuff.  I will keep everyone posted for sure.  I appreciate all the help and I'm printing this stuff off for my mechanic to review.  If a miracle happens and i gt home tonight, fire it up and she runs like a 2008 model....I'll be sure to let every know.

[skipn]

Bowmaga,

     Sounds great........pit and everthing must be nice.

since you have been around tri axles and probably some heavey equip this is just one more piece
of iron to contend with.

Good luck and let us know what you find out   There have been 3 or 4 posts so far this spring
of airing up problems   Seems like bus school has started

Skip

[bowmaga]

it will be nice if we can figure it out and fix it.  I will definitely let everyone know what the scoop is.  Don't worry, I'll be back with more questions....a lot more questions.  For now, this week, I'm going to concentrate on the interior, windows and water tanks.  I'll be back.

[bowmaga]

OK, I think I figured out how the tag axles valves work, and what position they should be in. I have a picture attached that shows the solenoids just down line from the valves. I have a dump air switch on my dash to dump the air out of the tags to get traction.  Would these solenoids go to that?  or what do they go to, cause one solenoids wires doesn't go anywhere.  The dark thing on the wire and solenoid to the right, is the rubber cap to the solenoid.   I can't seem to see where that loose wire goes?  does it go to the other solenoid?  Also, when I plugged the air compressor into the land line air connection and filled her up, she did the same thing..... curb side aired up strong, drivers side not so strong, but it appears its all in the drivers side rear that is not airing up completely.  Front looks to be getting good air on drivers side, but drivers rear is squatting real bad, which i think is also pulling the drivers front down.  Anybody have this happen or know where i should dig into first, in the rear, to try to resolve this problem?

[buswarrior]

Hello bowmaga.

That picture appears to be of the tag fender, just inside the curbside, side engine access door?

That is an unconventional install, the solenoids for reducing the air pressure to the tag bellows is mounted up on the bukhead, above/behind the engine, reached down through the hole in the floor outside the washroom door.

Are they solenoids, or pressure switches? Looks to be tee'd in...

Seized tag axle shafts are common, the last owner didn't bother greasing all the zerks, or didn't know.

A pit is a busnuts best friend!

happy coaching!
buswarrior

[NJT5047]

Keep in mind that the front is leveled by the rear drive axle leveling valves.  The front is on one leveling valve that controls front ride height only.  Like a tripod. 
Your pix show low-pressure switches.  They aren't solenoids.
They control the tag idiot lights.   
The tags are usually controlled by a pair of regulators that are set to 35 lbs.  The tags always run the same pressure.  They don't level  per-se. 
A damaged, flat for whatever reason, tag bag would not have much effect on the ride level.
There should be a couple of valves just to the right of the pressure switches.  Those control tag inflate or deflate.  You can tell when a tag is inflated by reaching behind the tag wheel and feeling it up....be gentle.
A few MC9s had dump valves controlled from the dash...but they only dumped air.  Didn't lift the tags.   The electric solenoid valves are usually under the bus...betweent the regulator and the tag bag.   If they are still there at all.
Unfortunately, tags that won't move are stuck in the axle tube.  Grease the hell out of both tag tubes and drive a little and see what happens.   That is a tough item to fix if they don't free up with minimal help.
Keep in mind that your bus has air beams.  you may have a leak on the top of the failed side.
This might be hard to hear because it's exhausting beneath the floor.  A leak would also cause the air compressor to cycle frequently and the bus would bleed off air quickly when shut down.
That isn't so hard to fix ....block off plates will solve the air-beam "blues" problem. 
What corner has the new air bags?  They should be obvious?  Hope it isn't the sagging corner?
JR

[bowmaga]

No, the opposite tag Axel got the new air bag.  I could see it tonight when i did some investigating and feeling her up.  All the other bags look the same, double donut looking bags, and the tag on the curb side has is just a straight sided bag.  The drivers rear corner is the sagger.  When sitting in my driver way, aired up from my compressor, the curb sides airs up enough to left the tag off the ground 3"-4".  Drivers side tag is still barely touching the ground. It looks like its getting air....just not enough.  Can the drive axle leveling valves in the rear fix this problem.  Can they be adjusted?

Are the air beams on an MC9 connected?  My bus seems to hold air for quite a few days before retreating down to her lowest position? And i can't hear any leaks. 

This not being level will bug me until i get her fixed.  She looks like she has hydraulics under her going down the road....front right corner up, back rear left corner riding low.....looks like if she leans any more she'll just roll over and play dead.

[bowmaga]

My next question is that I "think" I've read...The rear leveling valves are above each end of the drive axle (in front of the air bags). Each valve will have a linkage that attaches to the axle.  If my drivers side rear is sagging low but getting air....can i adjust these valves to make it right?  Anyone know how, anyone done it before?

[skipn]

Bowmaga,

    pages 12-7 through 12-11 in the maint. manual. 

   Sorry but I have never had to adjust my levelers.

Skip

[JackConrad]

Leveling valves do not control tag axle air bags, only drive axle air bags. You said curbside tag clears the ground when drive axle airbags are inflated. This should not happen. Either you have a stuck tag axle or not enough air in the tag axle air bags. Tag alxe air bags should have 35 PSI.  Jack

[PP]

I'm an idiot! With that said, take the rest of this with a grain of salt . Reading through the entire thread again and pondering all that you've described, it sounds like your tag axle is definitely hanging up. Even with flat bags it should be sitting on the ground when the rest of the bus is aired up. I suspect it corroded in place from lack of greasing and sitting too long. (Secretary spread  ) The second thing that you appear to have described is a bent or rusted up leveling linkage on the driver's side. Don't worry about the front at this point, it only goes up and down, not side to side. Leaning is controlled at the drive axle, but you've probably figured that out already from all the wonderful comments previously posted. Worry about the tag dropping second, after you get the lean situation sorted out at the drive axle. The leaning will be a lot simpler to fix than the hung up tag. Good luck and don't give up, we're all pulling for you 
Will

[DrivingMissLazy]

I'm an idiot! With that said, take the rest of this with a grain of salt . Reading through the entire thread again and pondering all that you've described, it sounds like your tag axle is definitely hanging up. Even with flat bags it should be sitting on the ground when the rest of the bus is aired up. I suspect it corroded in place from lack of greasing and sitting too long. (Secretary spread  ) The second thing that you appear to have described is a bent or rusted up leveling linkage on the driver's side. Don't worry about the front at this point, it only goes up and down, not side to side. Leaning is controlled at the drive axle, but you've probably figured that out already from all the wonderful comments previously posted. Worry about the tag dropping second, after you get the lean situation sorted out at the drive axle. The leaning will be a lot simpler to fix than the hung up tag. Good luck and don't give up, we're all pulling for you 
Will

I agree with everything you have said except I think the tag axle should be repaired first. If it is down on the passenger side and up on the driver side, that could cause the bus to tilt toward the driver.

Richard

[PP]

Quote "I agree with everything you have said except I think the tag axle should be repaired first. If it is down on the passenger side and up on the driver side, that could cause the bus to tilt toward the driver."
"Richard" Unquote


Thanks Richard, but wouldn't it lean even before he aired it up if it was a seized tag axle causing the lean?