Mc9 Airstep

kvan · June 27, 2009, 10:07:15 PM

I know there are quite a few conditions that have to be met in order for the air step to operate but what actually triggers the step to extend? Is there a microswitch on the door linkage that triggers the relay? Thanks

Jerry32 · June 28, 2009, 04:08:13 AM

I don't know but my 102A3 has a switch next to the door switch that extends the step when the door is open. when the door closes the step comes in automatically. Jerry

johns4104s · June 28, 2009, 05:28:14 AM

Kvan,

Were did you buy your MCI 9 air step?

John

luvrbus · June 28, 2009, 07:06:34 AM

John, the best place to buy you a air step is from a school bus wrecking yard Blue Bird used it on some models be sure and get the control valve it cost about 200 bucks new from Blue Bird. I have the # where I buy the valve for less than 100 bucks from another source if you find one without the valve good luck

belfert · June 28, 2009, 07:16:45 AM

Are air steps that much better than the electric steps used on regular motorhomes?

My air step is long gone probably due to an errant driver and I bought a set of electric steps I need to install someday.

cody · June 28, 2009, 07:22:57 AM

At some point i want to bring my iggle back up to the original ride height, at that point I'd like to add a step of some sort, right now I carry a wooden box that serves double duty, when parked it's a step, when moving it holds my power cord.

luvrbus · June 28, 2009, 07:25:18 AM

Brian, they are made better the motor on the electric steps are a problem some times it is only a wiper motor, but losing one is why I tie the air step it to the parking braking when the brake is released the step will retrack but we each do it our own way. good luck

kvan · June 28, 2009, 08:24:02 AM

The airstep was on the bus when I purchased it. It looks like it is a factory installation as most of the install agrees with my mci books. The lock cylinder in the book shows to be electric where as mine is air but it is an mci branded cylinder. I cannot determine what tells the step to move out. If I look at the schematics for the step they talk about different terminals on the relay that energize but I only have one set of leads that go to the electric/air valves for the cylinders, controlling both the slave and the lock. The electric lock on mine is non existent so that portion of the schematic is incorrect.

bottomacher · June 28, 2009, 02:43:39 PM

My MC9 step extended only by flipping a momentary toggle switch, and the door closer handle overrode it, so that it automatically retracted when the door was closed. I have no way of knowing if the arrangement was stock, but it was foolproof.

paul102a3 · June 28, 2009, 03:34:00 PM

Kvan,

My 102A3 has the factory airstep and I was wondering the same thing, does it automatically extend when you open the door. I spoke with someone that drove several 96s and 102s and he says that they only retract automagically. He claims this was a safety issue as MCI didn't want the step the extend and possible hurt someone. I don't really know if this is true but it makes sense.

There is a microswitch that the triggers the step to retract located just behind the entrance door air cylinder. I found it when I was looking to fix my air door system. My door does not open or close with the air cylinder and I assume it is an electrical problem.

My dash also has a two position momentary switch to extend and retract the step but it will only function if the door is opened a small amount releasing the microswitch. It appears the microswitch serves two functions. It triggers the circuit to retract the step and disables the momentary switch on the dash.

FWIW, I am in the middle of rebuilding my air step. One of the previous owners hit something and bent one of link bars as well as the step itself. The air cylinder leaks from time to time when retracted so it seemed like a good idea to fix the damage.

Everything is now straight and I will be calling MCI on Monday to see if the special bolts that attach the link bars to the steps are available as well as a rebuild kit for the air cylinder.

Paul

kvan · June 28, 2009, 04:30:21 PM

Quote from: paul102a3 on June 28, 2009, 03:34:00 PM
Kvan,

My 102A3 has the factory airstep and I was wondering the same thing, does it automatically extend when you open the door. I spoke with someone that drove several 96s and 102s and he says that they only retract automagically. He claims this was a safety issue as MCI didn't want the step the extend and possible hurt someone. I don't really know if this is true but it makes sense.

There is a microswitch that the triggers the step to retract located just behind the entrance door air cylinder. I found it when I was looking to fix my air door system. My door does not open or close with the air cylinder and I assume it is an electrical problem.

My dash also has a two position momentary switch to extend and retract the step but it will only function if the door is opened a small amount releasing the microswitch. It appears the microswitch serves two functions. It triggers the circuit to retract the step and disables the momentary switch on the dash.

FWIW, I am in the middle of rebuilding my air step. One of the previous owners hit something and bent one of link bars as well as the step itself. The air cylinder leaks from time to time when retracted so it seemed like a good idea to fix the damage.

Everything is now straight and I will be calling MCI on Monday to see if the special bolts that attach the link bars to the steps are available as well as a rebuild kit for the air cylinder.

Paul

Hey Paul At one time my air step worked just fine. If I set the toggle under the dash to Auto the step extended when the door was opened and the air brake was set, and closed when the door was closed. If the toggle was switched to the other position it moved to the up position and stayed there as long as the toggle was in that position.
Currently it is not doing anything, When I picked it up from storage the step would retract on its own but needed a little help to extend. Then it stuck down and would not retract at all so I removed the lock cylinder and it moved to the up position but now will not extend. That is why I am trying to determine what triggers it so I can start testing. On my Wanderlodge there were microswitches mounted down on the step assy that told the system it was either up or down but I find no such switches on the mci. My bus was converted by Marathon and I do not have any info on what changes they made to the system.
I also would be interested to know the cost of a step slave rebuild kit as mine leaks in the up position.
Thanks Karl

paul102a3 · June 28, 2009, 06:53:38 PM

Karl,

I'll let you know the availability and cost of the rebuild kit as soon as I find out.

Paul

RJ · June 28, 2009, 09:31:07 PM

Kvan -

My (fading) memory of the MC-9 air step is that there's a microswitch that contacts the door closer mechanism.

When you open the door, the switch allows the dash switch to extend the step, but only if the parking brake is set. I do not remember the step automatically extending when you opened the door, the driver had to trip it manually with the dash switch.

When you close and latch the door, the step retracts automatically.

Now, this might be a operating circuitry clue - IIRC, the step wouldn't operate if you turn off the door claw that pulls the door tightly closed when you lock the door handle. Possibly the two circuits are interconnected??

You might want to give Luke @ US Coach a call 1-888-262-2434 (9-5 M-F Eastern) and see if he can assist.

Altho a popular option, the air step didn't survive revenue service very long, drivers did a really good job of tearing them up/off the buses.

The other thing I remember vividly about the MCI air step is that it was VERY unstable if the coach's air pressure was way down. For example, in the morning, with low air pressure, if you'd locked the door with the key but not slammed it hard enough to activate the dash door closer lock, the step would move under you as you tried to use it to board the coach. Once the air pressure came up, it was solid again. Often had to keep passengers from boarding until it was safe to do so with those steps.

FWIW & HTH. . .

paul102a3 · June 29, 2009, 06:47:42 AM

Just got off the phone with MCI and the rebuild kit for the air step cyl is $48.55 plus shipping from Kentucky.

I agree with RJ, if the step is not locked in the retracted position, you have a dangerous situation.

The air step lock system on my bus is damaged which allows the step to hang loose until the bus is aired up. In addition, the step doesn't fully extend so you have the combination of an unstable step along with a small area to place your foot.

In my case, I believe the air lock cyl is OK and repairing the bent link will allow the lock to engage.

belfert · June 29, 2009, 10:16:59 AM

Quote from: paul102a3 on June 29, 2009, 06:47:42 AM
Just got off the phone with MCI and the rebuild kit for the air step cyl is $48.55 plus shipping from Kentucky.

If you order online with MCI, the shipping is free. (No recent experience, but I have never paid shipping.) They have also mentioned a service fee for orders under a certain amount placed by phone. Anyone can request an online shopping account at MCI's website.

Mc9 Airstep

cody