Air Suspension- Help fixing 1986 MCI 9

[Beau]

Hello, i have a hose hanging out the bottom of my mci9 1986. It’s spewing air when I turn it on.

It’s hanging right in the front middle as far as foot from the nose of the bus.

The air bags for the suspension don’t blow up. It prevents me from making wide turns instead the wheels cut into the wells. I bought it with this problem and don’t have any info about it from the seller.

I feel like I couldn’t reattach the hose and it could be an easy fix. I’m just not sure how. I’m not sure how to jack this big baby up. Anyhow I wanted to know if anyone had any advice on fixing it?

[Beau]

So the hose the was spewing was half way cracked. It’s plastic. I guess from 86 so. Here it is

Anyway it snapped off when I pulled on it.
Can anyone tell me what this kind of hose is called?

[rossvtaylor]

The proper tubing is called DOT air line and if you search with that term you'll find lots of sources for the tubing and fittings. It's a poly or nylon line and super durable. I have buses older than yours which show no sign of cracking or aging on the air lines...and I've not seen any with plastic fittings as that appears to be. Our MCI MC-7 sure doesn't have those.

I cannot tell for sure, but it appears that is not the proper line...but the photos don't confirm that.

Our local NAPA carries the fittings and DOT air line tubing, too, so you might check locally. If you can get to the other end, you can replace the length with proper fittings which will thread into the leveling valve and tank.

Be super careful beneath the bus! People have been crushed. I wouldn't go anywhere you might get crushed if the bus were to drop, unless you've got proper cribbing or jack stands. Be safe and keep us posted!

EDIT to add a link to examples: https://shop.hoseandfittings.com/cat...air_brake.html

[Beau]

https://youtu.be/sUZdyLP8KZ8

Here’s what it’s looking like
The hose towards the end of the video near the front is what’s spewing air

[Beau]

I linked a video of it in a response, a moderator has to check it I guess.

[rossvtaylor]

Until we can see the video, and get more info about where the line is broken, here's a bit of info about the suspension system.

The pressure line for the front air springs will come from an auxiliary air tank. That single line will run to a leveling valve, somewhere over the front axle. The leveling valve has an arm on it, with a rod that drops down and connects to the axle. From the leveling valve there with either be a single line to a tee, or there will be two lines...either way, those go to each air spring (air bag).

Where is your line broken?

[Beau]

https://youtu.be/sUZdyLP8KZ8

[Beau]

“Spewing air. MCI 9 hoses” by Beau eat butterfly. YouTube Should be on there. I know it’s a strange name. But the video is there!

Thankyou for the responses I’m in a sticky situation trying to get it moved before the new year.

[rossvtaylor]

Here's the link to your video: https://youtu.be/sUZdyLP8KZ8

But I cannot even see your air springs in that video...and I don't see the leveling valve shown either. Can you post some pics or a video of the air bag lines and the leveling valve? Those lines shown sure don't appear to be the suspension air lines...they're too far forward. And like I said, I've never seen plastic fittings on them.

[Beau]

I’m starting to think it could be for ac perhaps.

I put a coupler on the 2 lines. Connected them. Now it’s spewing else where. I’ll add photos

I guess I’m wondering is the dot cable what could be used for the air Suspension?

[Beau]

The photos

[rossvtaylor]

In the photo with the electric air valve, the large black line should be the air inlet. It looks like those white lines are on the outlet side. If that valve is stuck open, you could remove the black line fittings and put a cap on it...or, probably easier, trace it back to a tank and disconnect it there...then put a plug in the tank fitting.

I have no idea what those are for, but they do not appear to be part of your suspension system. But, if that black line is bleeding air from your auxiliary tank then that loss of pressure would prevent your suspension from airing up. Normally, the suspension won't air up until your pressure gets up to at least 60 psi and possibly closer to 90.

[Beau]

youtu.be/_2VYVprNRXg

Here is a video I just posted before seeing your response.

I’m gonna try tracing it etc and get back to you.

And of course thanks so much for the help.

[rossvtaylor]

Originally Posted by Beau

youtu.be/_2VYVprNRXg

Here is a video I just posted before seeing your response.

I’m gonna try tracing it etc and get back to you.

And of course thanks so much for the help.

I still cannot see the air bag lines or the leveling valve, but I'm pretty sure the white lines you are showing have nothing to do with suspension. I guess...a pretty good guess, I think...that the air leak, though, is preventing the buildup of pressure to inflate the air bags.

One question - what pressure are you reaching on the dash air gauges? It it getting up to 120 or so? Or staying lower, like 80-90?

As far as that black line goes, a quick and dirty way to see if stopping that air leakage helps solve the issue is to disconnect it from that electric valve and fold it back, crimping it, and tape it over.

[Crown_Guy]

Everything Ross said. I'll add that that electric solenoid valve is likely part of the door closing Clamp claw that grabs and pulls the door securely shut. It's very normal and on all MCI's with the one piece sedan doors, which were the vast majority of MCI's until they started in with the two piece opening transit type doors for special customers. If that conversion has modified the entry door to the point that the original door closure sequence and hardware are no longer in place, it may be that the very large and sturdy door clamp claw is no longer being used. It may even have already been removed during conversion. If that's the case you should be able to simply do as Ross suggested and seal off all the air lines and the taps from the accessory air tank that were used to feed it air. No need for it or it's air lines at all and it removes one more point of failure simplifying the air system in the process.

I'd STRONGLY suggest that you visit and get set up with the site dedicated to owners and users of all things Coach. They know the vehicles and systems and there are many folks there who can help with expertise and sources for parts. Not so much here, Ross is an exception, as am I, and a very few others.
www.busconversionmagazine.com

P.S. I checked the pics again and it seems indeed that the entire clamping air cylinder and mechanism has been removed entirely. That compartment is where it all was housed with the clamp itself affixed close to the door opening so it could grab the socket built into the door and pull it closed. It's all gone now. The purpose of that solenoid may actually be in doubt as to if it were part of the original system or something added by the conversion Fairy. You should have already acquired an original Manual for your bus, Right?, both repair and parts manuals, with which you can then easily look up the original system parts and operations. This will tell you if that solenoid is original equipment or a conversion modification with some other unknown purpose.

Do as Ross suggests and seal off the lines to stop the leak and see if the air pressure builds up now in the accessory tank and the air gauge gets to 120 psi. If that happens and everything seems to still work properly then you can trace it down at your leisure to find out what the mysterious solenoid is supposed to be doing. Without full pressure in the accessory air tank almost none of the main bus systems will operate. Air suspension, W/S wipers, parking brake release for starters. That brings up another potential problem you'll face..... the DD3 parking brake system. But that's another story all together. One problem at a time....

By the way, be patient when airing up the bus. A fully discharged air system on an MCI can easily take as much as 15 minutes or more to air up all the tanks. This is at low idle. Even if it still has the fast idle system in place, don't be surprised that it won't function either until the air pressure comes up to about the same 60 psi or so. The fast idle is an air operated series of actuators on the governor housing that require a minimum air pressure to work.

This also means that once started the normal engine shutoff will NOT function to stop the engine until the air pressure comes up to the same 60psi. Yep, that's also an air actuated system requiring 60psi work. Have I mentioned yet how much the MCI's used air pressure to operate most of the basic systems on board. They used air a LOT.

You're dealing with a whole different universe when working with a Coach. MCI's for my money are the preferred ones, since I have so many years and miles driving and owning them in service. But for someone like you with no previous experience it's going to be a monstrous learning curve and you'll need help and advice from others who know about them and give you real world knowledge on what to do and how to avoid disasters along the way. Trust me. You don't know yet what you don't know. Remember what Yoda said..... "You will be"

[rossvtaylor]

Ooooooo....the claw! <said in a Toy Story squeaky toy voice>

Good call on that, Mike!

Edit: to add context for those who didn't have kids in the Toy Story era and haven't seen the movie 100 times... https://youtu.be/N-Esh4W3dfI

[cadillackid]

these threads are great!! every time i thinkl "how cool it would be to have a coach bus".. I see on e of these threads and im cured.. my little shorty school busses are enough.. and when im ready to dabble.. i have the fish bowl to look forward to... lolol

[Beau]

Thanks for all the response yall. Gonna head over to the couch bus forum with this.

Lastly just gonna write this

I’m currently having problems starting the bus engine now. My way of testing where the pressure coming from.


I haven’t put a drop of Diesel in it since I bought it a few months back. I’m going to put some in it and see if it helps. Update just put 5 gal in and not turning over. It’s seems to be quite full of diesel. No telling how old it is.

A friend said the engine sounds great. We drove it around the block and the engine was good but the turning was rough. That was 2 days ago. No air suspension so the wheels busted up into the wells. The problem I’m working on. I hope this engine deal isn’t too bad.

Anyway

I’m looking for the leveling valve here. I guess that’d be helpful to know the location of when I get to the coach bus forum.
If anyone has any tips on where to find the leveling valve. Let me know!

Thanks for the responses yall

[Beau]

The engine problem is this. I start it, it runs for a few seconds and then dies.

[rossvtaylor]

Originally Posted by Beau

I haven’t put a drop of Diesel in it since I bought it a few months back. I’m going to put some in it and see if it helps. Update just put 5 gal in and not turning over. It’s seems to be quite full of diesel. No telling how old it is.

A friend said the engine sounds great. We drove it around the block and the engine was good but the turning was rough. That was 2 days ago. No air suspension so the wheels busted up into the wells. The problem I’m working on. I hope this engine deal isn’t too bad.

Anyway

I’m looking for the leveling valve here. I guess that’d be helpful to know the location of when I get to the coach bus forum.
If anyone has any tips on where to find the leveling valve. Let me know!

Thanks for the responses yall

What engine do you have in that? Is it a 2-stroke Detroit? Regardless of the type, no diesel likes to run out of fuel. If you run out of fuel, it can be a pain to prime the fuel system to get it running again. If there's ANY possibility it's low on fuel, I'd add at least 10 gallons before proceeding. Most bus diesels cannot just self-prime if you run out of fuel. So if that's the issue, you'll need to prime it and we'll need to know what engine you have to guide you on that.

The fuel filters could be clogged too, which would lead to running poorly and/or running and stalling. The fuel filters...there should be 2...look like big oil filters. If you spin them off, see that they're full of fuel. If they're empty, you ran out of fuel and lost prime.

And the leveling valve should be where I described it, above the front axle in the middle. But before you get to messing with that, did you cap off or crimp that black air line we mentioned? That would be my first step.