Leveling revisited for MCI 102

[Jim Blackwood]

Dave, how are you hooked into your air bags?

Jim

[sledhead]

removed the original lines from the leveling valves and installed the new lines . before you do anything you need to measure the height from a level surface from the road to in my case the lower belt line at all corners ( wheels )  . record it and that is the ride height you want when driving . after the system is installed then you set the road height from the control unit at each corner by pushing in on each valve until you get the same height . record that and that is the level you want when driving . the rest is the adjustment when you are parked as all you do is adjust the air up or down for the proper level . very simple .
in the 10 years I had the M C I there was never any problems with the system , it would hold the level for months .

dave

[Jim Blackwood]

Sounds simple, but when you say record the height, how are you doing that? I picture walking around the coach with a yardstick, adjusting the air, rinse, repeat however many times it takes?

Jim

[buswarrior]

Sounds simple, but when you say record the height, how are you doing that? I picture walking around the coach with a yardstick, adjusting the air, rinse, repeat however many times it takes?

Jim

On initial set-up, yes, then you take note of the air pressure applied to each corner, and you have your running heights/pressures, barring significant addition or removal of weight from the coach, in which case, out you go with your yardstick to set new targets.

Hard to beat the simplicity of 4 push/pull manual valves with accompanying individual gauges.

Happy coaching!
Buswarrior

[Jim Blackwood]

Sounds good to me. I just ordered four valves:

Order summary
Manual Paddle Valve Switch Control Air Ride Suspension AirLift Performance 21703    
Manual Paddle Valve Switch Control Air Ride Suspension AirLift Performan...

Total: $53.72
https://www.ebay.com/itm/112611240096

...and some levels. Since I happen to have a matched set of four 0-150 psi air gages I'll use that plus a similar one if I need it. Is that for your auxiliary air compressor?

I can install a gage panel down to the right against the defroster/AC cover.
Those valves look pretty good and got nothing but good reviews and the price was very good. I may put those in the left hand switch panel if there's room. Might depend on where I put the levels. I'd liek to be looking in about the same area while leveling. Anyway that's an important next step because if I can level the coach that way it'll make interior construction easier. Probably install the system and do the levels last. I'm guessing you just used standard 1/4" air brake line and fittings?

Jim

[sledhead]

yes that is correct
" On initial set-up, yes, then you take note of the air pressure applied to each corner, and you have your running heights/pressures "
after I recorded the pressure's it never changed much as I never over loaded any corner . some times I would add a little more air to the rear if I was pulling a trailer.
I made sure there were no connections in each line to the air bags so no leeks . I had to make a box to install the valves and gauges in that was deep as there are a lot of t 's for the connections and it takes up a far amount of space  box was about 9 " x 6 " buy 4 " deep and I installed it right beside my driver seat . I used the 5 th gauge for incoming air and yes 1/4 " air lines dot and all fittings were brass not push in crap

https://photos.app.goo.gl/nUQrHKo3pcPgyiF96

dave

[Jim Blackwood]

https://www.mcicoach.com/service-support/serinfo/serinfo12D.htm

The above link should take you to an explanation of the kneeling feature on MCI 102D series busses. There is a second bulletin for the electrical side. I got there with a search and I'm not sure I can get back there, but the info is available if we can find it.

So reading through the explanation, as regards the front axle it seems this Kneel feature might give us a handy way to level that end of the bus, with possibly as much as 12" of adjustment, more likely a bit less. The ride height spec is 11".

The key is Sol1 (NO) and Sol2. Now Sol2 is normally open, supplying air from the leveling valve. During kneeling air is vented through Sol1 which is de-energized. It can be energized to raise the bus. What we need to sort out is a way to raise or lower the air pressure on demand with minimal or no changes to the existing plumbing, the electrical side being generally easier to modify. However, having the air control panel in the front LH bagage bay seems to open some options.

I've not sorted it out yet. We can possibly either do it through Sol2 via the LH leveling valve, although that would seem at first to require extra plumbing, or possibly through SOL1 directly although that would seem to require the solenoid to stay energized. From there it gets more complicated since we want to add a little air and then seal it off. Or alternatively, provide either a regulated pressure or a switched supply depending on coach level condition. Probably best to keep those two options in mind for later.

If I can find similar pages for the operation of the leveling system (and also the rear suspension) it should be possible to sort something out that will suit our needs. Just something I happened across.

Here's the electrical side:
https://www.mcicoach.com/service-support/serinfo/serinfo12E.htm
Reading through this it seems an electrical solution could be feasible.

Jim

[Jim Blackwood]

Ideally I think that maybe this can be done without having to get under the bus. That would be a plus.

Jim

[buswarrior]

Is the front not a single circuit of air? It will go up and down, but no side to side control?

If your DL has the option to raise its skirts at the rear, getting that halved so each side back there is controlable would be neat, and then you have your 3 legged stool.

As for powered or not, the coach was wired from a seated coach mindset, swap NO for NC, and vice versa, because you need it to work from a camper mindset.

Happy coaching!
Buswarrior

[buswarrior]

And designed so that a single dash switch will put everything to "high ride"

Way too many places to drag a 45 foot coach on the ground, getting in and out of parking lots, etc.

Like an excited cat, up on tip toes, back arched, fur on end, maximum clearance underneath...

Happy coaching!
Buswarrior

[Jim Blackwood]

Good idea.

Well, I've not located the leveling valves on the front yet, apparently the left one controls rode height and the right one controls a switch so that's a bit of a puzzle, but the line from the right front bellows goes into the spare tire well and to what looks like a manifold block. Not sure about the left one yet but they are both supposed to go to some complex double check valve/maybe shuttle valve thingey somewhere, maybe that mess with all the green 3/8" hoses connected to it. Or that may be something else entirely, looks like they didn't use that valve for another year or so.

Anyway it looks like one of those hoses off the manifold block goes to a small air tank in the left front compartment under the driver. Looks like an accumulator because I think there's only the one line. Maybe it improves ride quality.

Unfortunately each drawing leaves out critical information and my bus doesn't exactly match any of the drawings, so there we go.  Here's a shot of my control panel.

By inference it would seem the two sides are T'd together but I have no actual proof of that yet. Be nice if I could just find a spot to add air, power off, and raise the front. But so far it may not be possible without at least another valve. Even then I don't know what the manifold block in the spare well does to it. It's quite the puzzle.

Jim

[buswarrior]

Similar to my D3.

It is frustrating, the documentation for the MC8 was exact and detailed.

Someone at MCI must have put an intern in charge of the books during these years, and intern who was focused on nothing to do with accuracy or completeness...

Happy coaching!
Buswarrior

[Jim Blackwood]

OK, now that valve at the bottom with the white 1/4" line coming out of it. Do you have any idea where that line goes or what that valve does? Any chance it goes to the kneel switch outside the door? It looks like we have exactly the same controls, so maybe we can figure this out.

My trip down to the Louisville MCI is growing closer and I plan to ask about the maintenance manual when I get there and hope someone can come up with the right one. I hope they have something better than the one I downloaded. In the meantime it looks like tracking down lines is going to be the way of it.

Jim

[Jim Blackwood]

More info from direct observation. First, the switches by the door are electric, not pneumatic. Second, the manifold block in the spare tire well may have a supply line to the front level valve but does not appear to connect to either of the airbags. Third, there only appears to be one leveling valve. Fourth, both front airbags appear to connect to the leveling valve but at different points rather than on the same "T".

So it may come down to how the exhaust air from the leveling valve is handled. We know we can exhaust the air via the kneeling controls.

Jim

[Jim Blackwood]

I'm now very close to the conclusion that manual controls and gages are the way to go here. The leveling valve is going to try to level the bus no matter what you do I think, and with a direct line it has the final say in the matter. The kneel function disables one part of that but if you use the raise position on the switch it continues to try returning it to ride height even while it is raising. At the very least the automatic controls will limit the range of leveling. And the bus now has far too many automatic functions. Almost like it has a mind of it's own.

So I've blocked the front end up under the skid rails and if it's dry tomorrow I plan to slide under and look at the level valve and the lines. Because the main lines to the front air bags are 3/8" it will not be possible to air it up as quickly with the 1/4" manual valves that I have. However I can minimize that by only using the smaller lines right around the valves. With this setup the auto leveling will be disabled. This is one time when I think it might be a good idea to remove the associated hardware and lines. If I look at it and think I see a different way I will let y'all know.

One possible way might be with a valve inline between the leveling valve and the air bag. It would need to be a somewhat fancy valve and I'm not sure there is just one that would do the job. Maybe a 3-way and two simple on/off solenoid valves. So the 3 way would divert between the leveling valve on one inlet and the air jack control on the other. I think it would have to be solenoid operated, powering up when the engine power comes on. Then the other two solenoid valves could add or remove air. But that basically means one 3-way and 2 solenoid valves for each air bag or each axle end. So 6 3-ways and 12 solenoids. That's likely to get a little expensive. But the upside is that no changes would be made to the OTR system, and the leveling system, being electrically activated could be automated rather easily. Or, the jack side of the 3-ways could be brought back to the manual valves and air gages. That actually is beginning to sound like the best solution.

Or maybe a hybrid with solenoids to vent the air. That way lowering could be accomplished quickly, and there would still be an air line to read pressure. Running 4 wires and four 3/8" tubes to the rear would be easier than eight 3/8" tubes, and cheaper. Maybe even enough to offset the cost of the solenoids. Go ahead and run 8 wires and if the supply solenoids are added later the wiring is already there and the tubes still feed the gages. That doesn't sound like too bad of a plan. If pressure side solenoids are expected, 1/4 lines could be used. If part of the install, 1/8" would be adequate. (and I have a big roll of that)

With that, if the bag is inflated beyond standard ride height (not unlikely), when the engine is started the leveling valve will lower it. If it is low it will bring it up. So the only thing needed when heading out would be to start the engine and by the time air pressure is up the normal ride height will be restored. It also will not interfere with the rear raise or kneel. The only real issue I see is that you would have up to six 3/8" solenoids powered up all the time when driving. Probably no more than 6 amps of current though at the most. Failure would mean reverting to manual control at that corner.

There is a possibility that the front leveling valve has separate valves on each line. That would allow some roll control. If that is the case they should be individually controlled. Does anyone have experience with those?

Jim