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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: sailerman on June 26, 2006, 02:46:09 PM



Title: Bus will not air up
Post by: sailerman on June 26, 2006, 02:46:09 PM
Howdy to all my fellow bus enthusiasts I have a problem and am asking for some suggestions’ or ideas. I have a NJT MCI 9 with kneeling option. I started it the other day and it would not air up. You can here the air coming out of the system some where between the front tires. I am assuming that the safety valve is stuck open and all the system air is going out this valve. My symptoms are;
1. Sounds of lots of air coming out from between the front tires.
2. Air gage on dash indicates only 10lbs of air.
3. Hooking up an aux compressor to rear air input does not help.
4. Bus will not rise on airbags.
5. I have to shut down engine from the rear by manually shutting off fuel at the governor. 
    One of my problems is that the bus is now so close to the ground I cannot get my air over hydraulic jack under the lifting points on the axel or body, it looks like I have only 5 inch’s of clearance.
 I have no air to release the parking brakes. Can I use the emergency fill that in the compartment under the driver’s station to release brakes or will the air leak out the safety valve?
If I can release brakes do you think I could get it to go up a small ramp?
Any ideas out there, I’ll post the ones that work for others to have for future reference Thanks……..


Title: Re: Bus will not air up
Post by: Buffalo SpaceShip on June 26, 2006, 03:03:19 PM
I wouldn't try moving the bus up ramps if the brakes don't work. Seems to dangerous to me.

HF sells a low-profile 12 ton jack that would have no problem getting under the obstruction(s) to jack. Pretty affordable, IIRC. I have one for jacking up the front of my bus. I also have a 20 ton for the back axle.

Be super careful under there if you do get it jacked up.

bb


Title: Re: Bus will not air up
Post by: Busted Knuckle on June 26, 2006, 03:39:17 PM
3 sugestions here! First with air hooked to the bus lay down by the front axle and stick yer head in behind the front wheel you shoul see 2 tank hanging vertically(you'll only see the bottom end!) but take something to tap on the tanks while airing it up! Don't beat on the tanks just a few good hard taps, if the leaking doesn't stop go to the next step! Yes Harbor Freight does sell some low profille jacks but you actually should be able to lay the jack on the side to slide it under the bus then back beside the wheel you can stand it back up right beside the wheel on the front axle is a jacking pad that sticks out to the front! Should be able to get it jacked up a little to put a board under the tire, then reset the jack and keep doing this until you can either get to where you can use the jack under the body jacking point, or keep raising the tire a board or 2 at a time until you can get under it! Or lastly & only if you have some one helping you, place a board in front of both steer tires, air it up at the emergency release and have some wheel chokes placed in front of the drives about a foot & a half to stop you(the helper will need to place one behind the drive when you get it up to the front one!)! This should give you clearance to use a jack! DO NOT TRY TO DRIVE UP ON MORE THAN 1 BOARD LIKE THIS UNLESS YOU ARE LOOKING FOR A DISASTER TO HAPPEN!!! AS I SAID ONLY IF THE OTHER TWO WON'T WORK & A LOW PROFILE JACK IS NOT READILY AVAILABLE! Now once you get it where you can get to it there are 3 likely places your leak is coming from 1 of the air tank drains, the air drier pop off valve!, or the leveling or kneeling valve you should be able to locate the leak by putting air to it after getting it where you can slide under it! Once you've located the leak if tapping near it doesn't make it stop let us know where it's leaking from and we'll help ya from there! BK  ;D  8)  :)

;D 8) Only 5 more days to VOTE when is best for you, an your's for the "TN Fall Bus Bash at Knuckle's! 8) ;D

:) ;D 8)  We gonna have a BLAST at the"TN Fall Bus Bash" at Knuckle's  8) ;D :)


Title: Re: Bus will not air up
Post by: gumpy on June 26, 2006, 05:22:20 PM
Try hitting the brake pedal a couple times.

Also, open the spare tire compartment and see if it's coming from inside there.



Title: Re: Bus will not air up
Post by: Busted Knuckle on June 26, 2006, 06:59:16 PM
Yeah thanks Gumpy I always forget the simple things! LOL! BK  ;D


Title: Re: Bus will not air up
Post by: NJT5047 on June 26, 2006, 07:02:03 PM
Here's another idea....look up in front of the RH front tire and you'll see the front leveling valve that is mounted on the Kneeling valve.  The kneeling valve is likely causing your problem.  It'll exhaust all your air faster than you can make it.  Turn the wheels to the right, grab a hammer and whack the kneeling valve...DON"T whack the leveling valve or any air lines...! :o  The kneeling valve is a large cast iron valve on which the front leveling valve is attached.   And if that solves your problem, never again use the kneeling feature.  Don't just disconnect it though...it has an interlock and you don't want get involved in that unless you know exactly how the kneeling system works.  It's complicated to say the least. 
The door switch is next to the kneeling switch, but the kneeler is covered by a bomber door.  Leave it shut. 
The kneeling valve can be removed, but you'll have to replumb the leveling valve.  I eliminated the kneeling valve and the front leveling valve from my NJT.   Use a regulator to control ride height.  The rear is still on leveling valves, but the weight of the front never changes (unless of course you could afford to fill the fuel tank...and no one has that sort of cash!) on a conversion, so all one has to do for a simple and very dependable front air suspension is to take control.   About 60 lbs will give you a nice factory ride height.
You might also try playing with the kneeling switch and see if it shuts off.  The kneeling valves wern't used much and crap causes them to fail.   Hope this is your problem....could be a blown air suspension bag, failed air beam if you have an 83...and it could be any air line or tank located under the front (that is where the air is leaking?),   If you were dinking with the kneeler, it's probably your problem, if not... ???   
The exhaust for the kneeling valve is the sintered brass (don't hit that either) thingy on the kneeling valve.
As others have described, the air tanks drains may be leaking, but if air is leaking in profuse amounts, check the kneeling valve.
The shop air should  supply enough air to raise a badly leaking bus so that you can get jacks under the jack posts.  That's a start.
Post a descripition of what component exactly  you find leaking and  we can be more descriptive regarding repairs.  By turning the wheels to the right, a smallish person can crawl into the area between the RH tire and the frame...find out what is leaking.   
I doubt that the brakes will release unless the leak is remedied...not really sure about that.  
Good luck, JR     


Title: Re: Bus will not air up
Post by: Busnut83 on June 28, 2006, 01:41:14 PM
Sounds like the same post I did on May 11,    It was the DRYER,,the kit cost 6bucks and took 15 min,,, you need 2" wrench to remove the valve...

I posted a reply after I found the problem but it was deleted I think because I said I found a repair an idiot can do.... I was joking about myself....


Title: Re: Bus will not air up
Post by: Dallas on June 28, 2006, 02:34:19 PM
Sounds like the same post I did on May 11,    It was the DRYER,,the kit cost 6bucks and took 15 min,,, you need 2" wrench to remove the valve...

I posted a reply after I found the problem but it was deleted I think because I said I found a repair an idiot can do.... I was joking about myself....

It wasn't deleted by any of the moderators, but may have disappeared if it was in response to a post another member who quit made.

Dallas,
All Around Nice Guy
And Hero Extraordinaire!