MCI DL3-45 Air Leveling Questions

plyonsMC9 · August 17, 2025, 10:45:54 PM

Good evening Bus Folks!,

It's been a while since I've last posted, but now I'm back to bus projects and taking a break from travels.

The front end of our DL3 is lower than the rear end, and as a result, the ride is rougher up front. It can be downright painful going over potholes! Also, the bus has new shocks on the front - just installed.

I also have a tilt to the driver side that I'll be working on as well.

For the front leveling procedures, my manual says "The link or lever should be moved up to raise the ride-height level or down to lower it". If I understand this correctly, I should move the link up, and I believe that would be done by moving the link up on the bracket on the axle.

Am I adjusting this linkage correctly to raise the front end/ E.g., moving the link UP on the bracket? Pictures are attached.

Thank you all!,
Phil

thomasinnv · August 18, 2025, 07:11:18 AM

That depends on how much adjustment is needed. Large adjustments by moving the bolt to another hole in the lower bracket, small adjustments by loosening the nut on the upper arm and adjusting the lever of the valve. The maintenance book will have the proper procedure and measurement. Also make sure that the new shocks are not limiting the travel as that will have a negative impact on ride quality.

Also I'm assuming that the picture was taken without the bus being aired up? If not you have another problem.

plyonsMC9 · August 18, 2025, 12:43:15 PM

Thanks Derrick!,

After airing the bus up my measurements on the driver side body-to-axle clearance is at about 11". So that is per-spec per the book. (Manual snapshot attached) I've never tried this procedure before and unfortunately I had not measured the body-to-axle clearance before the first adjustment. Mistake on my part. Visual inspection from the outside of the coach looks better after the adjustment and raising the PSI to above 100.

But I'd like to verify: whether moving the moving the link UP on the bracket is how I raise the front end up?

If the air leveling valve's job is to detect the bus body height and then either add or release air from the suspension to keep the ride height constant, then by moving the link up on the bracket (attached picture : Air-LevelingValve-Front-Raised.png - bolt in middle position) then have I told the valve that the body is higher, and so it will respond by decreasing the amount of air in the air springs and lower the front end? Which would be the opposite of what I'm trying to do?

Starting to think I should be sure the left-to-right working exactly right as maybe that could affect the front level.. maybe. Going to get into that, extra jacks to the rear end now. So far whole bus is up on ramps.

Thank you all!, studying and trying to get this sorted out correctly.

Best Regards, Phil

thomasinnv · August 19, 2025, 07:49:24 AM

If you move the lower mount to a higher hole, it will raise the bus. Get the front ride height in the ball park, then check the side to side and adjust as necessary. (Rear valves). Once the side to side is correct make your final adjustments to the front. Set the height according to the book, a small deviation can greatly effect the ride quality.

plyons · August 19, 2025, 10:05:22 PM

Thank you Derrick!,
It is great to get that confirmed. And I appreciate that assist.

As I was going over the setup on our DL3, I'm beginning to question the RV air leveling system. I think MCI only built 7 of these RV systems - or so I was told by one of their techs. The RV valves are very old, and one "may" be leaking. My battle has been a 2" lean to the front / driver side. My air bags are 11" on the passenger side rear (perfect), 10 3/4" driver side rear. Today it was 11 3/4 on the passenger side front, and 10 3/4" driver side front air bag (top of air spring plate to bottom of the air spring plate). It's not consistent. Yesterday that passenger front spring was 11" I have been struggling w/how this situation is possible since left to right should only be controlled by the right and left rear air springs. I've been filling the bus up to 115 PSI via my shop air compressor. Though I'll occasionally start up the engine to compare PSI results - engine compressor vs shop compressor. But now I'm thinking that the MCI RV air leveling system may be getting in the way. At least it's a possibility. When running over the road the bus the RV system should be disabled, and just the OTR air spring control should be in control. So the theory goes.

MCI support doesn't much like trying to help w/ that, but since it's one of their systems they do try. It was built a LONG time ago.

Kind Regards, Phil

thomasinnv · August 20, 2025, 07:53:22 AM

Is the RV levelling system utilizing manual valves? Or is it an electronic system? It wouldn't happen to be a Valid Manufacturing system?

plyonsMC9 · August 20, 2025, 11:36:20 PM

Hi Derrick!,

I believe these are manual valves. (pix below). In the RV-NamePlate.png image the name of the MCI RV leveling system. I'm able to call into MCI support and they will make a best-effort to support it, as they manufactured it.

The other 3 diagrams and pictures detail parts of the system. (well, there are the 3 valves, solenoid, plus a spare in the foreground of the picture).

With best regards, Phil

Jim Blackwood · August 24, 2025, 04:39:05 AM

I looked at using the air bags to level the bus but it seemed like the biggest issue was finding a controller that could hold the bus level. It's a large platform and requires small increments. After thinking about that and air's tendency to escape, I decided a mechanical system would be easier to live with. It's unfortunate that nobody makes a really good system that I know of but I have gotten pretty good results so far with my semi-trailer landing gear in a tripod configuration with electric gearmotor drives. Building the structure to mount them was probably the biggest challenge but really it was just basic fabrication. Just on a larger scale than usual.

Jim

thomasinnv · August 24, 2025, 09:37:13 AM

Quote from: Jim Blackwood on August 24, 2025, 04:39:05 AM
I looked at using the air bags to level the bus but it seemed like the biggest issue was finding a controller that could hold the bus level. It's a large platform and requires small increments. After thinking about that and air's tendency to escape, I decided a mechanical system would be easier to live with. It's unfortunate that nobody makes a really good system that I know of but I have gotten pretty good results so far with my semi-trailer landing gear in a tripod configuration with electric gearmotor drives. Building the structure to mount them was probably the biggest challenge but really it was just basic fabrication. Just on a larger scale than usual.

Jim

I went with a Valid system. Not too bad to install and it is fully automatic.
https://validmfg.com/product/vehicle-leveling-system/

Jim Blackwood · August 25, 2025, 04:16:27 AM

Looks pretty good, how much did they ding you for on that one?

Jim

luvrbus · August 25, 2025, 06:41:08 AM

Any of air leveling systems are not bullet proof since they are electronic HWH has the best system but very expensive ,took me a few try's to figure out if you dump the air bags and start over the $ Thomas DC power compressor would do a good job only coming on a couple of times a night do to temperature changes I did like the Active air adjusting to highway slopes till a sensor or circuit board would fail. I had HWH hydraulic levelers on my Eagle they were a lot better than air ,you could put those down for months with no changes and you didn't have the movement like with the air systems either. I have close friend with liner actuators on 4 corners of a MCI he has used those with 8 inch lift and 2500 lbs rating for 20 years without any problems

thomasinnv · August 25, 2025, 07:53:01 AM

Quote from: Jim Blackwood on August 25, 2025, 04:16:27 AM
Looks pretty good, how much did they ding you for on that one?

Jim

If memory serves the complete system with everything needed for installation was around $3600 but that was about 8 or 9 years ago. Valid used to make all the components for power gear air systems and everything but the hydraulic components for the power gear air/hydraulic combo systems years ago before powergear started manufacturing their own components in house. Now power gear is owned by Lippert. Another great company gone down the toilet. Lippert seems to screw up everything they touch.

Jim Blackwood · August 26, 2025, 05:04:41 AM

I built my landing gear based system on the cheap, but I did buy new jacks, I think they were around a couple hundred each. The gearmotors to drive them I bought from salvage. If bought new they could easily run a grand each. Then there were the control and drive components and installation. So in the final tally not really any cheaper if you paid someone else to do it and our time is worth something, right? On the plus side it is rock solid when leveled.

Jim