Righr front air bag will not fill

AC MC9 · October 19, 2010, 01:55:42 PM

Good Day Everyone,

I would like to pick your brains a little. I have a MC-9 (1989) with the 6V92TA and 5 speed. The issue I have is the right front air bag will not fill. I have had my unit sitting for about 6 months in storage and now have found a place that I can work on my unit and get working on the conversion. The last few days I was checking over the bus to get it ready for the move and found that the right front air bag will not fill. I have checked and could not find any leaks in the air system using soapy water on the fittings. All other bags fill up without an issue. (The right front air bag is in good shape and dose not leak or have a tear.)

So I have some questions:

1) Any ideas where to look to see if I can get this bag to fill?
2) Can I move my bus 5 miles with the air bag deflated to my new location? If so, what should I be careful of?

Any help would be greatly appreciated.

I have been lurking in the background for some time now. But am hoping to be able to add so good advice to this form in the near future since I will be tacking apart my bus when I get it moved to it's new home.

Thank you for your help.

robertglines1 · October 19, 2010, 02:25:15 PM

does drivers side fill ?.I think they are on the same leveling valve..been awhile since I worked on Mci. If two level valve ck one on that side rod might be betached..or if one and tee coming out of it there might be a peice of debree in line..blow out.keep us posted..Bob ps eventer1 is close to your location is building a 89 prevost now.

AC MC9 · October 19, 2010, 02:28:08 PM

Yes, the drivers side fills. I will look again but I beleive that there is only one leveling valve on the front. I will let you know what I find.

robertglines1 · October 19, 2010, 02:40:35 PM

there is no restriction (valve etc )past t if is one. blow out line make sure coach is blocked up don't want you smashed.if you take line off t the other side will fall! blocked up ck for blockage in tee if clear ck for crimped of blocked plastic line..you can just loosen fittings most time and do this..your secondary air shoud be above 60 before the systems that air up bags kick in..is your primary going to around 120..secondary should also...

AC MC9 · October 19, 2010, 02:51:37 PM

My primary air system reached 120psi. I will be blocking the unit before I go under it to check the air line and to bleed the air off incase of blockage.

Dave5Cs · October 19, 2010, 03:25:13 PM

Why you are under there check your air beam for leaks and rust if any also. Spray them all around with Extra soapy water. If you have" ride rite Firestone" gauges for the front on the dash unscrew the plate and check for leaks at the hose connections on the back and the little tiny hoses that goes to the other button Also any tees that come off it.

Dave

bobofthenorth · October 19, 2010, 03:33:57 PM

UMM .... this is going to sound really dumb ....... mainly because it is dumb. And don't ask me how I know this but .........

A rear airbag that isn't filling can make it look like one of the front bags isn't filling. Whack the bag that appears to not be filling and if it fights back then go looking at the back end of the bus.

Like I said, don't ask me how I know all this.

gumpy · October 19, 2010, 05:48:45 PM

Just a curious question, but did you check both air bags on the front right side? You do know there are 2 bags on each side?

The MC9 should have copper lines connecting the single leveling valve to each side air beam.

Try Bob's suggestion as he's correct. A rear problem can make it look like a front problem. Also, check to make sure it's not just parked in a hole because that can
also make it look low.

If you get under there, spray the crap out of the bags and air beams, as well as the copper connecting lines. If still no bubbles, pull the line
off the air beam and see if it's blowing air. Unlikely it's plugged, but could have some rust in it from the air beam.

My bet is on a leaking bag or beam. It's a pretty simple system. Not much can go wrong with it.

AC MC9 · October 19, 2010, 05:53:23 PM

Thanks for all the info. In the next couple of days I will be back to try all the suguestions. Once I complete this I will post what was found and the correction.

Once again,
Thank you all for your input.

Arsenio

bevans6 · October 19, 2010, 06:02:00 PM

Did MCI switch to single air bags on later MC-9's? I thought they all had a pair of dual convoluted air springs per side front and rear. How could one front airbag not inflate? As noted, the front suspension of a stock MC-9 would have the front air springs fully connected side to side, and all cross leveling is done by the rear suspension. It could be completely normal for one side to have normal air pressure in it, yet still be down on the bump stop depending on what the rear suspension was doing.

Brian

gumpy · January 21, 2011, 01:05:28 PM

Hey, Arsenio, we never did get an update on this post. Did you solve your problem?

AC MC9 · January 21, 2011, 03:46:22 PM

Sorry, Never got back to the bus to check what is going on. Have been going through some personal thing for the last few months. The bus is still at the old location and looks like it will stay there until spring, or if we are lucky and all this snow melts before spring, I can check it out and get back to the board with the answer.

Arsenio