Rear bags not equalizing/ leveling

Dietrichfarms · September 18, 2014, 05:30:46 PM

1978 mci 7, air pressure comes up right away but driver side rear is 1 3/4 inches lower than right side. No leaks that I can find, have tapped on air block in rear, tapped on equalizer/leveling rod and valve, lubed all pivot points up. Still no help. Any ideas?

Dave5Cs · September 18, 2014, 08:57:10 PM

Did yo spray soap and water on your bags and at the top of your air beams if you have them? Spray your leveling valves also. Doesn't take much.

AndyG · September 21, 2014, 12:16:27 PM

Have you changed anything that shifted weight in the coach dramatically? Water or fuel tanks, generator? There is probably a leveling valve on each side of the bus on the drive axle. One of your valves is faulty/plugged or out of adjustment.

Dietrichfarms · September 21, 2014, 04:05:56 PM

Yes I have,installed granite counter about 125 lbs on that side didn't think about that can't find any leak on leveling valve so will check for stuck or plugged tks.

Lin · September 21, 2014, 04:17:00 PM

Make sure there is no play in the linkage to the ride height control valves. Even a small amount of play will change the ride height. If everything checks out, and the ride height is still unequal, you can adjust it by adjusting the linkage. On my 5a, I think that the air bags are supposed to be extended about 7.5 inches, including the plate, when aired up. If the 7 is different, it should say so in your manual. Whatever you determine the correct height to be, adjust accordingly. Remember, it is just as possible that the higher side is off. Of course, try to make your measurement on level ground too.

gus · September 21, 2014, 07:58:31 PM

Quote from: Dietrichfarms on September 18, 2014, 05:30:46 PM
1978 mci 7, air pressure comes up right away but driver side rear is 1 3/4 inches lower than right side. No leaks that I can find, have tapped on air block in rear, tapped on equalizer/leveling rod and valve, lubed all pivot points up. Still no help. Any ideas?

Remove the leveling valve link end and try moving it up/down by hand. This will quickly tell you if the valve is the problem (It probably is). It is slow so give it time to respond.

BE CAREFUL!!

Oonrahnjay · September 21, 2014, 08:18:03 PM

Once you get this straightened out, you might want to park your bus on a level spot and adjust the leveling valves so that it sits as you want it to. Then, measure from the ground to a spot on the body (a good place is right at the high spot of the wheel arch trim). Once you have this measurement at all four wheels, you'll be able to take a tape measure and do a quick check ("Is the bus sitting lower on one corner than the others) in 20 seconds or so. You'll be amazed at how much "eyeball" is not a correct measurement, and also how much a bus that sits level on a level surface will lean a bit on a sloping surface. But at least you'll know quickly if you have a problem, and, if so, how much of a problem that there is. If you have a problem, you will have to go through the full analysis and trouble-shooting process but the quick check usually helps.

Lin · September 21, 2014, 10:02:32 PM

BTW, do you have the same tires on both sides?

Dietrichfarms · September 22, 2014, 08:02:15 AM

Yes have same tires on both sides when I measured to start this check it was on concrete slab 1 3/4 of from driver to pass side. Will get parked on slab again and block up for safety and disconnect linkage and check. Tks

lvmci · September 22, 2014, 08:40:45 AM

Hi Dietrich, Clifford showed me a mechanical leveling device, infront of my rear wheels on my MCI5A, it looks like a boxend wrench with slight bent ends bolted to the valve mounted to the wheel well and the axle, mine are painted red. My bus was leaning to one side, more in the front than in the back, it was loose, but hard to see how the back controlled the front, when the nut finally came of the the bolt and the arm came loose, the same side would barely raise, when I checked what Clifford showed me, it was completely off, hanging from the rear mount on the axle. A simple nut and tightening, fixed the problem, so checking both air level control arms, might help, lvmci...

TomC · September 22, 2014, 08:46:03 AM

Make sure you drive the bus up on blocks high enough to clear when the air bags are deflated with you laying under the bus when you start adjusting the air valves. Disconnect both connecting rods. Once you think you have it leveled, deflate all the way down, then re connect the air valves to the connecting rods. You might have to do this a couple of times. If you can't get it level, just go and buy two identical new leveling valves. They are not expensive, and probably will solve the problem. Good Luck, TomC

Lin · September 22, 2014, 03:31:07 PM

If it is just a matter of needing an adjustment, you can replace the rods with turnbuckles to make both sides adjust to exactly where you want them. If you do, I would put a couple of nuts on the turnbuckle to be able to lock it in place.

gumpy · September 22, 2014, 06:14:26 PM

Maybe you should put some information in your profile so people can figure out where you are located. Who knows? There might be someone nearby who knows a lot about this
stuff and would be willing to come over and help you figure it out. Busnuts can sometimes be that way, or so I hear.

I spent yesterday evening helping a young newbie pull the rear duals of an MC7 to get to a seized DD3. He was very appreciative and sucked up any and all information I happened to
let slip out. I expect I'll be hearing from him again in the near future asking all kinds of interesting questions about his new hobby.

Just a thought.

craig

Dietrichfarms · September 22, 2014, 07:13:58 PM

I will update my profile, I'm in Blanket, Texas that's dead center middle of the state. I was back under the bus and yes I will not move anything till have blocked up. But I did find that there is only one leveling valve on the drive axle and it's on drivers side, output line going to that bag has a Tee in it and goes over to the other bag., being its new plastic airline I assume PO did this at some time? Does that point more to a bag leaking?

gumpy · September 23, 2014, 05:31:36 AM

Well, as they say, there's your problem!

No, it doesn't point to a leaking bag, it says the PO was a rocket scientist!

Your bus needs two leveling valves on the rear axle, one on each side. One valve will not compensate for side to side loading differential.

You should probably consider removing the PO's experiment, and put the bus leveling system back the way it was engineered back in the 70's ( 50's?). There
should be 2 leveling valves on the drive axle, and one on the steer axle.