1998 DL3 extreme right tilt

[Swadian]

Went and started my 1998 MCI 102DL3 and once aired up it began an extreme tilt to the right. First time this has happened since I bought the coach. Leveling valve and leveling valve linkage are NOT bent, broken, or out of adjustment. There's also NO air leaks and both tag axle dump valves are CLOSED. Also, ALL the LH air bags are overinflated, and ALL the RH air bags have no air pressure at all. Entrance door works fine.

The "arm" on the leveling valve will NOT move, EVEN IF it's disconnected.

I don't have a replacement leveling valve nor can I reach the line connected to the RH drive axle valve to see if there's any air coming through it.

Also, the coach is NOT kneeling.

Finally, the coach ONLY tilts when the engine is running.

I drove for 750 miles without trouble. Then, I parked it for 1 week and when I came back it started tilting. Coach was parked for a year before I drove the 750 miles however, and I do have all the manuals and schematics.

What do I need to do?

[chessie4905]

Could be just an inop leveling valve which could make the other bags look over inflated. Does it have a curb side drop option?

[Swadian]

No curb side option. MCI says that the valve may be stuck in the exhaust position. How do I get it unstuck? Should I hit it with a stick?

[richard5933]

Had this happen to my coach once while it was over the pit at US Coach. Bill had been trying to fine tune the adjustment on the height control valves, and one got stuck like this. We never figured out exactly what caused it, but after moving the lever to the extremes it seemed to start playing nice again. We ended up swapping for a new valve since we were right there and it was easy. I don't think that the new valves are as robust as the OEM parts.

[Swadian]

Moving the leveling valve to the extremes is impossible since it won't budge and is hard to reach without a pit. I know it's supposed to be able to move but on this coach it won't move.

According to MCI and my schematic, either the rear junction block is plugged or the RH rear leveling valve is plugged or stuck in the exhaust position, or the double check valve is plugged.

Do you want me to hit it with a stick, or do you want me to hook up a line from the LH tag axle dump valve to the RH tag axle dump valve in an attempt to unblock the line from the other side?

[richard5933]

Assuming that you've got the bus properly blocked so it's safe to get under it...

When this happened on mine we just disconnected the arm on the height valve and moved the arm. Can't tell from your posts if the arm is still connected on yours.

Odds are you'll have to get under the bus to handle this, whatever the problem is. Are you able to get it blocked up where it sits?

[luvrbus]

The DL should have a kneeling option sometimes mine needed the kneeling option turn off and to level,they have a raise and lower option on the rear too try raising and lowering it   

[Swadian]

Again, the arm is still connected but it will NOT move. Kneel has nothing to do with this. The coach isn't kneeling and the kneel never worked anyway.

I've ruled out:
1. It's not the tag axle dump valves.
2. It's not the kneel.
3. It's not the front junction block.
4. It's not the front double check valve.
5. It's not anything connected to the entrance door (since the door still works).
6. It's not the "arm" or anything visibly connected to the leveling valve (nothing will move, but nothing looks broken or damaged either). Emphasis on "visible".
7. It's not the air bags or a shock absorber.
8. It's not an air leak.

My best guess is that the leveling valve froze inside, hence the lack of leaks or visible damage and also why the "arm" won't move.

[richard5933]

How are you trying to move the arm if it's still connected? One end is connected to the valve, the other to the chassis/body. It's got to be moving, or it would have bent or twisted as the body went up.

[6805eagleguy]

Yup, ain’t gonna move while connected

[richard5933]

In order to investigate the height valve, you're going to have to get underneath. To do that you're going to have to raise the bus AND block it so that it's safe to get under it. Don't even stick an arm under the bus otherwise, especially since the air suspension system is already giving you problems. One piece lets loose and you get smooshed. Won't be enough room to live underneath if it drops.

Once you get under, you can remove the bolt from the distant end of the arm - the end connected to the body - and see if it's frozen.

Hopefully others with more experience will chime in. There are three leveling valves on most buses - two in the rear for side-to-side and one in the front for nose up/down. They all do interplay with each other. I'm not familiar with the particulars of your set up, but there are others on the board who are and hopefully they'll help out.

To me, all other issues can be eliminated the valves are cheap enough to just replace rather than be messed with. The one on the lower side can be the culprit even though you don't hear it leaking or find evidence of a leak - they can leak internally and send the air back to the tank.

[Swadian]

Richard, you don't understand. I disconnected the arm, THEN tried to move it, and THEN when it wouldn't budge I reconnected it.

Also, I DID get under the coach on some 6 occasions since it started tilting but every time to no avail.

In fact, I disconnected and tried to move it TWICE, but after both attempts failed I gave up and simply reattached the arm. That's why I said that, at the present time, the arm is indeed connected but not that it'd do me any good to disconnect it again.

I don't know if it's frozen. All I know is that after doing exactly what you're telling me to do, it didn't move.

I've done everything you're suggesting already short of replacing the valve. It didn't work.

[windtrader]

I have zero experience but it seems like removing the arm upset one of the valves, maybe making it stick or jam. If it was working properly before this action, then it's most likely what you did create the issue. At least, you can trace it down much easier as you know the state of the system pretty well.

[richard5933]

Not sure why you're yelling...I'm just another bus nut trying to help. I understand the frustration, but like I said I'm only trying to help.

If the arm is indeed frozen, then first I would do if it were mine is to replace the height adjusting valve. If you don't have another source, Luke at US Coach should have them.

If you got under the bus, I hope you had it blocked up well. Otherwise, you're damn lucky to be alive. If that thing had moved and dropped the bus it's all over.

[Swadian]

Not yelling. Just emphasizing so that I don't have to repeat myself. 

The arm is not frozen. MCI Tech Support hypothesized that the inside of the valve itself is frozen.

Took this pic from under the coach. Highlighted with the green arrow (and the green circle) is what MCI thinks is frozen inside. Obviously, there's no way to tell from outside.