GV (Unihome) Air Step Mod

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GV (Unihome) Air Step Mod

July 10, 2016, 06:54:47 pm

As part of my continuing study of the air system on our coach, I decided to delve into the Air Step. We don't actually have any problem with the step (at this time). I just wanted to see how it worked, and I also was thinking about doing a simple mod. When it is "down" in the open position, the step on our coach fills up with water when it rains. If it is up, it stays dry. If I anticipate showers, I go out and close the step "manually", by pushing it up to the "closed" position. This is only possible when the air system has leaked down to almost zero. If there is any pressure in the system, then I can't close the step.

My idea was to install a couple small ball valves, which would allow me to isolate the step control from the air system pressure, and to bleed the pressure off the step cylinders. That would allow me to close the step manually at will, and also would prevent any air leaks through the air step cylinders during long term parking. I already had all the parts necessary on hand, so the "out of pocket" cost would be negligible.

Removing the electric air solenoid control is pretty simple. I took some photos of it right after I pulled it out. Every fitting was covered with a heavy accumulation of some kind of soft thread compound. It looked like it was applied with a spatula! Once I started removing the fittings to clean them up, I found they had also been installed with a thick layer of teflon tape. Every one of the tapped holes had a big glob of teflon tape in it below the fitting. The imbecile who put that thing together apparently believed "If a little bit is good, then a LOT must be better!". I am sure this was done post production - it was certainly not OEM quality work. It is a wonder the air valve functioned at all, with all that loose trash inside.

The top row of photos (below) will give you an idea of the condition of the controller when removed.

Once I got everything cleaned up, I took one photo showing the "stock" configuration of the controller (#5), and then 3 shots of the new modified manifold. It has one pressure gauge that shows system air pressure (Front tank pressure), then a ball valve to isolate the step control, then the pressure regulator (with gauge), then the 2nd ball valve to bleed off the step cylinder pressure. Pretty simple.

I will add another post below with a couple more close-up photos of the step controller components. It might be a good reference in the event that anyone ever needs to order replacement parts for their air step.

Re: GV (Unihome) Air Step Mod

Reply #1 – July 10, 2016, 06:58:26 pm

More photos:

I'll add one more post tomorrow after I get the manifold reinstalled in the coach.

Re: GV (Unihome) Air Step Mod

Reply #2 – July 10, 2016, 07:00:40 pm

Chuck....You can also pull down on the black adjuster knob turn it and drain off the excess air to raise the step then lock/push it back up....at least on our coach it works that way. Did I miss something..

?

Hans

Re: GV (Unihome) Air Step Mod

Reply #3 – July 10, 2016, 07:05:49 pm

Hans,

I never thought to try that...but my luck if I had started messing with the pressure regulator, it would break. It was also pretty hard to reach where it was originally installed. My little ball valves, on the other hand, will be very "handy" (ha, ha).

Re: GV (Unihome) Air Step Mod

Reply #4 – July 10, 2016, 07:12:11 pm

I had the same issue..saw the "push lock" on the black knob and figured it must also pull down. Turned it, Voila it bled off the air and raised my step manually,before I do this I check the pressure on the gauge usually around 60psi and after the weather passes turn the knob clockwise and get the pressure back up. . Now every time it rains I go out and bleed of the air. I inadvertently found this when turning that knob without pulling it down and found the unit loose in my hand

Would love to see your mod, as always enjoy your posts. !!

Hans

Re: GV (Unihome) Air Step Mod

Reply #5 – July 10, 2016, 08:48:38 pm

Nice photos.

We are all for having a plan to optionally keep outside step up, and to keep water from accumulating inside step as it will corrode the step. But any plan that keeps the step up all the time, can be asking for a very bad fall leaving the coach. We all expect the step to be there and it sounds dangerous to have it be missing sometimes.

Our method of pulling the step up when desired, is to add an inside switch that activates the 4-way solenoid when ignition is in off positon, so the solenoid thinks the ignition is on. And the coach normally will lower the step when the door is opened even with the ignition on, so the we can easily keep step up when parked, and still have the step automatically lower when we open the door to leave. But this method only works when there is air tank pressure to move step.

For water accumulation, we silicone sealed the large surface seams and rivet holes to keep water out and also drilled a few extra strategically located holes to maybe drain any water when step is down or up.

The switch method has been written up and used by several coach owners. And there may several reason to keep step up, like for increased security, to keep someone from stepping up to look in door window and if parked next to a high curb or rock.

BTW, we did the use Chuck's idea for the inside step slide, except we used a 3-way 12-volt solenoid that cuts off the air and bleeds out the cylinder air, and we use it all the time to keep air pressure out of the slide cylinder (to length its life), except when we want to open or close the step slide. This new solenoid is controlled by an inside switch.

We thought about a similar 3-way solenoid on outside step cylinders, but decided against it for safety reasons.

Notice the solenoid's screwdriver adjustment bolts on Chuck's photos, as they will restrict the exhausting side of the cylinder, to slow down the banging up or down. They act as dampers and are also a vent allowing air out, but keep dirt from entering the valve.

Re: GV (Unihome) Air Step Mod

Reply #6 – July 10, 2016, 11:10:41 pm

Quote from: Barry & Cindy – July 10, 2016, 08:48:38 pm

Notice the solenoid's screwdriver adjustment bolts on Chuck's photos, as they will restrict the exhausting side of the cylinder, to slow down the banging up or down. They act as dampers and are also a vent allowing air out, but keep dirt from entering the valve.

Barry,

Thanks for the (as always) thoughtful and informative comments. I'm glad you cleared up the purpose of those adjustment screws. I could tell they were exhaust ports, but could not figure out what the screw was for. Now it makes sense!

I actually shopped for a 3-way electric solenoid valve exactly as you described, to use for this mod. But then I decided to go for the simplicity and reliability of the manual valves. I will have to be careful about when I use this feature, to avoid anyone taking a tumble. If it turns out to be a hazard, I will re-think my approach, and probably change over to the electronic solution.

Re: GV (Unihome) Air Step Mod

Reply #7 – July 16, 2016, 01:02:24 pm

Update: I kept going back and reading Barry's thoughts about ways to control the entry step. The more I thought about it, the more sense his approach made to me. It is simpler, cheaper, and easier to install than my "mechanical valve" method. There is a very clear explanation of what he proposes, here:

Modify outside air step wiring to allow step to retract when ignition is off...

While I was reclining in the storage bay, working on my (overly complicated) step valve mod, I noticed 3 wires leading up into the door area. Investigation lead me to the switch in the entry door frame. Interestingly, on my coach, the switch is not magnetic, but just a simple "push button". Very similar to what used to be installed (back in The Day) on every car door to control the dome light. See photos below. My switch has 3 wires: yellow, red, and purple. Testing with a multimeter shows the yellow wire is "hot" with ignition "ON". With the push button extended (door open), the red wire is also "hot". With the push button compressed (door closed), the purple wire is "hot".

Looking at my step control air valve, I see the "hot" wire is red. I was able to trace it by hand back up to the door switch. The purple wire is just curled up in a loop under the shelf, behind my step box. The end was snipped off cleanly, but open. Good place for a dead short, if it ever contacted a "ground". Apparently, on some year/model coach, there was another device or solenoid valve in the step area that was activated by the purple wire when the entry door was closed. Not used on my coach - I taped the end for safety, but left the wire intact in case I ever needed it in the future.

To make Barry's mod, all I had to do was cut the yellow wire (C11 on my wiring diagram) where it passed through the storage bay behind the step. Added two extension wires to the cut ends, and ran them around to the corner of the small bay door opening right next to the entry door (my "tool box" bay). Mounted a SPDT (ON-ON) switch on a little bracket. Tapped into the adjacent bay light for my hot lead. All pretty simple, really. I can provide more details if anyone needs them. See photos.

Works great! Toggle in DOWN position, everything works just like factory original. With engine off, flip toggle UP, and step flips UP. While step is in modified UP position, if I open entry door, step drops back down (for safety). Pretty COOL!

I heartily advise all members to ignore everything I posted above about adding the complicated double ball valve manifold. TOO MUCH WORK! Barry's electrical solution is elegant and so easy to do... If you want to mod your step, follow his lead!

Re: GV (Unihome) Air Step Mod

Reply #8 – July 16, 2016, 01:15:21 pm

In case anyone cares, here is what my (now irrelevant) 2 ball valve manifold looks like installed. The big pressure gauge reads "Front" air tank pressure - the small one "regulated" pressure. I will leave it in place for the present, but eventually I will probably remove it, salvage the parts, and put the air line back to stock. While working in that area, I also cleaned up my "tire filler" air hose manifold. Added a pressure gauge (reads "Wet" tank pressure) and replaced the old "hose bib" type valve with a new quarter-turn ball valve.

Re: GV (Unihome) Air Step Mod

Reply #9 – July 16, 2016, 01:51:20 pm

Quote from: Chuck & Jeannie – July 16, 2016, 01:15:21 pm

In case anyone cares

I care, and it does not even concern me. That is quality work!

Re: GV (Unihome) Air Step Mod

Reply #10 – July 16, 2016, 06:31:59 pm

Sounds like a couple of projects for me to do to our coach. While I'm at it, I'll add a longer hose so that I can easily get to the left rear tires, and replace the angled head with a straight one. That should make it easier to fill the tires.

Re: GV (Unihome) Air Step Mod

Reply #11 – July 16, 2016, 09:06:21 pm

Chuck, Glad you found a safe solution to keeping your outside step in up position when parked.

Thanks for your comments. It is nice to know that our mod write-up on BeamAlarm.com continues to be a helpful guide.

Barry & Cindy

Re: GV (Unihome) Air Step Mod

Reply #12 – February 17, 2018, 10:14:22 pm

Quote from: Chuck & Jeannie – July 10, 2016, 06:54:47 pm

As part of my continuing study of the air system on our coach, I decided to delve into the Air Step. We don't actually have any problem with the step (at this time).
Removing the electric air solenoid control is pretty simple. I took some photos of it right after I pulled it out. Every fitting was covered with a heavy accumulation of some kind of soft thread compound. It looked like it was applied with a spatula! Once I started removing the fittings to clean them up, I found they had also been installed with a thick layer of teflon tape. Every one of the tapped holes had a big glob of teflon tape in it below the fitting. The imbecile who put that thing together apparently believed "If a little bit is good, then a LOT must be better!". I am sure this was done post production - it was certainly not OEM quality work. It is a wonder the air valve functioned at all, with all that loose trash inside.

Chuck,
My step controller solenoid and manifold had developed a bad leak even though it was working just fine also. I couldn't hear it hissing under the platform behind the step but the soap bubble test surprised me! It was gunked up just like yours and I found some metal in the manifold when I took it apart. I decided to replace everything since mine was hard to get to. I had to move the platform back that the inverter and aux pump sits on to get to it. I bought the replacement from Foretravel for about $200 including the mufflers and the pressure gauge as the old manifold and solenoid are obsolete.

The new one will fit in the same place but I had to tilt it back since it is taller than the old one and also had to drill two new mounting holes.

The manifold/solenoid part is an IMI Norgren V61R517A-A312JB.
The regulator is an SMC AR20-N02BG-Z-A.

Thanks for the heads up on this one. The step works just fine with no leaks. My overall leak down has slowed considerably and now it's on to finding the next one!

Jerry

Re: GV (Unihome) Air Step Mod

Reply #13 – February 17, 2018, 10:37:21 pm

Always makes me happy when a old post or thread proves useful to someone.

Re: GV (Unihome) Air Step Mod

Reply #14 – June 23, 2021, 09:24:56 am

Hello,
I am very new to all this. Can someone please let me know were I can find the air step
diagram on a 1993 u280?
Mine just stays down .

Thank you,
Cyrus Ardalan.

Re: GV (Unihome) Air Step Mod

Reply #15 – June 23, 2021, 11:42:30 am

Hey Cyrus, start by checking your door switch, make sure it's working.
I had to remove a wood grab bar to access ours.
Then move to more complex parts.

Re: GV (Unihome) Air Step Mod

Reply #16 – June 23, 2021, 01:53:41 pm

Welcome to the Forum Cyrus. Always glad to see more GV owners around the camp fire.

I don't know if there is a "air step diagram" anywhere to be found. if you will read through this thread from the first post, I think you will understand how the step is supposed to work. Then you just need to poke around the components on your step to see what is NOT working.

For the step to work, you need air pressure (at least 60 psi) and a correct 12 volt signal to the Norgren valve that controls the air cylinders. Plus, the air cylinders must be in working condition (not locked up internally from trash or corrosion).

As Phranko said, a good place to start is the door switch. On my coach it is a mechanical push in spring loaded switch, like cars back in the day used to trigger the dome light. If the engine is running and your system air pressure is up, then if you push the door switch in (like when the door is closed) the step should come up. When the door switch is popped out (like the door is open), the step should drop down. Note: on some coaches the door switch is magnetic rather than mechanical..

If these things are not happening, it could be a bad door switch, a wire broken off the back of the door switch, or a bad ground wire on the Norgren valve. If there is no air pressure going to the Norgren valve, it could be a bad pressure regulator.

If the Norgren valve is getting correct electrical signal and air pressure but still doesn't work, it could be plugged up inside with gunk.

If you don't know what a Norgren valve is or where it is located, then like I said, read this thread from top to bottom.

Re: GV (Unihome) Air Step Mod

Reply #17 – June 23, 2021, 03:41:52 pm

Welcome, Cyrus. Our 1993 U300 is like Phranko's and others, with a push button switch in the door jamb. Key off the step is out. Key on and air pressure, the door is step is up if the door is closed, down if the door is open.

You need both key on and air pressure to make the step move. When you get a chance, fire up the coach and build up at least 70 pounds of air. Leave it running and check the door. Does the step work properly? If not, start playing with things mentioned in this thread. I'd start by closing the door and trying to help the step close. Since the system wants the step closed, it might be that it just needs a little help. If you get it closed, open the door and see if the step opens. Again, that's what the system wants to happen, so see if your help gets it to do what it is supposed to do.

If you are able to make the step move you might want to see if you can figure out what's preventing it from moving by itself. The pistons may be shot, the hinge may be rusty, etc.

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GV (Unihome) Air Step Mod

July 10, 2016, 06:54:47 pm

Re: GV (Unihome) Air Step Mod

Reply #1 – July 10, 2016, 06:58:26 pm

Re: GV (Unihome) Air Step Mod

Reply #2 – July 10, 2016, 07:00:40 pm

Re: GV (Unihome) Air Step Mod

Reply #3 – July 10, 2016, 07:05:49 pm

Re: GV (Unihome) Air Step Mod

Reply #4 – July 10, 2016, 07:12:11 pm

Re: GV (Unihome) Air Step Mod

Reply #5 – July 10, 2016, 08:48:38 pm

Re: GV (Unihome) Air Step Mod

Reply #6 – July 10, 2016, 11:10:41 pm

Re: GV (Unihome) Air Step Mod

Reply #7 – July 16, 2016, 01:02:24 pm

Re: GV (Unihome) Air Step Mod

Reply #8 – July 16, 2016, 01:15:21 pm

Re: GV (Unihome) Air Step Mod

Reply #9 – July 16, 2016, 01:51:20 pm

Re: GV (Unihome) Air Step Mod

Reply #10 – July 16, 2016, 06:31:59 pm

Re: GV (Unihome) Air Step Mod

Reply #11 – July 16, 2016, 09:06:21 pm

Re: GV (Unihome) Air Step Mod

Reply #12 – February 17, 2018, 10:14:22 pm

Re: GV (Unihome) Air Step Mod

Reply #13 – February 17, 2018, 10:37:21 pm

Re: GV (Unihome) Air Step Mod

Reply #14 – June 23, 2021, 09:24:56 am

Re: GV (Unihome) Air Step Mod

Reply #15 – June 23, 2021, 11:42:30 am

Re: GV (Unihome) Air Step Mod

Reply #16 – June 23, 2021, 01:53:41 pm

Re: GV (Unihome) Air Step Mod

Reply #17 – June 23, 2021, 03:41:52 pm

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