Can’t get motorhome off leveling jack

[tvfrfireman]

I have a forty foot motorhome that is our first. I had a problem on our last trip breaking camp. Getting ready to go I raised all four jacks but the front left was fully retracted but sitting on the block I used due to having a low corner on our site. Once I set the block down under the jack when setting up, there was one and one quarter inch of space between the pad and wood block. When getting ready to leave I raised the jacks and started the engine to fill the airbags but the coach remained on top of the block. What happened to the one and one quarter inch space I had? We had to dig and chip away at gravel to get the block out. Is there something I am doing incorrectlyY. Thanks for any help.

[SuperBus]

tvfrfireman wrote:

SuperBus wrote:
You may have an intermittently failing leveling valve on that corner (for your air bags). If that is the case, obviously you'd want to get it replaced to resolve the issue. But, in the meantime, dumping air using your jack controller might correct the issue by moving the leveler through some of its stroke, thus getting it to allow air back into the air bag and raise that corner of the coach back up.

Thank you Super bus for your assessment. I am sorry I have not enough experience in these systems to understand what you think I should do. If there is something I could read that would help me to understand I would be grateful. I don’t understand what the jacks have to do with the leveler. Are these two different systems (the jacks and the self leveler)? All the jacks retract fully. It is that the front left jack was sitting fast on the wood block when the night before there was plenty of room between the block and the pad.

Well, don't thank me yet, I could be wrong! 🙂

They are separate systems, the valve I am referring to is part of your suspension. It is a valve mounted on the chassis with a linkage connected to your axle/wishbone/etc., set to a certain length. The job of this valve is to maintain ride height of your coach when the air suspension is active (i.e. your engine is on). For example, if you add a bunch of weight to a corner of your coach, the weight would cause the airbag to compress some. The linkage on the leveler will then move in conjunction with the connected suspension component, and the valve in the leveler will open an allow some pressurized air into your airbag to regain the ride height lost due to the compression caused by the extra weight. Vice versa, if weight is removed from the corner, the airbag would get taller, and the leveler valve would let some air out of the bag to get back to the same height.

The reason I suggested you consider this as a potential failure point is that when you level your coach, your airbags most likely exhaust thus lowering your coach and stroking the leveler valve to one extreme range of its motion, an area it doesn't go to often. From personal experience, I found a bad valve won't allow the airbag to fill back up properly after you've restarted the coach and raised the jacks. This would result in your jack pad still being in contact with the ground/block of wood/etc., not because the jack has an issue, but because the suspension did not fill up and lift that corner of the coach. As the block is taking up the small amount of clearance that would have normally been between the ground and the jack, it is still in contact.

[fj12ryder]

I don't know about normal procedure, but maybe your compressor is a bit weak?

[tvfrfireman]

fj12ryder wrote:
Can you raise the front end up again with the leveling jack, start the engine and pressurize the air bags? Maybe that would allow the vehicle to stay high enough to get the leveling blocks out.

My initial question pertained to whether the motorhome had lifted at all when the air bags were pressurized. Or if there might not be an issue with them.

I will give this a try. I will start the coach and fill the air bags and then store the jacks. Is this the normal procedure?

[tvfrfireman]

SuperBus wrote:
You may have an intermittently failing leveling valve on that corner (for your air bags). If that is the case, obviously you'd want to get it replaced to resolve the issue. But, in the meantime, dumping air using your jack controller might correct the issue by moving the leveler through some of its stroke, thus getting it to allow air back into the air bag and raise that corner of the coach back up.

Thank you Super bus for your assessment. I am sorry I have not enough experience in these systems to understand what you think I should do. If there is something I could read that would help me to understand I would be grateful. I don’t understand what the jacks have to do with the leveler. Are these two different systems (the jacks and the self leveler)? All the jacks retract fully. It is that the front left jack was sitting fast on the wood block when the night before there was plenty of room between the block and the pad.

[fj12ryder]

Can you raise the front end up again with the leveling jack, start the engine and pressurize the air bags? Maybe that would allow the vehicle to stay high enough to get the leveling blocks out.

My initial question pertained to whether the motorhome had lifted at all when the air bags were pressurized. Or if there might not be an issue with them.

[stevenal]

hysteresis in the level sensor system, that is the height difference between compressor on and off levels. Even though the suspension dropped, it was still within its happy zone.

[Dutch_12078]

tvfrfireman wrote:

way2roll wrote:
I would guess a combination of a few things. An inch and a half isn't that much space. My guess would be your tires were hot and higher psi when you set up camp. After sitting, the lower temp/psi caused your entire rig to sit lower once down off the jacks. If that's the lowest spot, that's where the weight will shift and cause the largest drop. Like another poster said, you could have jacked it up, put a board or 2 under the nearest tire and set it back down. Standard board would buy you the 1-1/2" to drive off it.

Thanks for your response. I would have jacked it up and placed a board under the wheel but am concerned about where to jack. I am not an expert on these rigs and would hate to damage a vital part.

Will your leveling jack extend enough to raise the tire off the ground enough to put a board under it? You may want to do both jacks on that end or side to avoid frame twist.

[tvfrfireman]

way2roll wrote:
I would guess a combination of a few things. An inch and a half isn't that much space. My guess would be your tires were hot and higher psi when you set up camp. After sitting, the lower temp/psi caused your entire rig to sit lower once down off the jacks. If that's the lowest spot, that's where the weight will shift and cause the largest drop. Like another poster said, you could have jacked it up, put a board or 2 under the nearest tire and set it back down. Standard board would buy you the 1-1/2" to drive off it.

Thanks for your response. I would have jacked it up and placed a board under the wheel but am concerned about where to jack. I am not an expert on these rigs and would hate to damage a vital part.

[way2roll]

I would guess a combination of a few things. An inch and a half isn't that much space. My guess would be your tires were hot and higher psi when you set up camp. After sitting, the lower temp/psi caused your entire rig to sit lower once down off the jacks. If that's the lowest spot, that's where the weight will shift and cause the largest drop. Like another poster said, you could have jacked it up, put a board or 2 under the nearest tire and set it back down. Standard board would buy you the 1-1/2" to drive off it.

[Grit_dog]

SuperBus wrote:
You may have an intermittently failing leveling valve on that corner (for your air bags). If that is the case, obviously you'd want to get it replaced to resolve the issue. But, in the meantime, dumping air using your jack controller might correct the issue by moving the leveler through some of its stroke, thus getting it to allow air back into the air bag and raise that corner of the coach back up.

A more likely scenario for sure. Because the ride height sensors should have allowed to hit the same height.

[Grit_dog]

wa8yxm wrote:
What happened? You loaded all your "Travel stuff" and thus loaded it down.. likely about 1.5"
This is easier with a car... Measure the bumper height with the car basically empty. Do this at the rear bumper.. Now open the trunk and set 3 or 4 5 gallon pails of water inside (however many you can fit) and measure the bumper height again.. Now remove the buckets .. carefully (you might put only 4 gallons in)

Each gallon is what about 8.6 pounds so 4 times 4 gallons is a bit over 250 pounds.. Now imagine all the stuff you put in the RV.

I’m trying to imagine any sort of reasonable scenario that compresses the front suspension an inch and a half due to loading up “travel stuff”. And even moreso how the camper got that much heavier “after” a comping trip where the same stuff goes home minus the heavy consumables.
But moreso I’m trying to imagine how even a wacky theory like that applies to air ride….

[SuperBus]

You may have an intermittently failing leveling valve on that corner (for your air bags). If that is the case, obviously you'd want to get it replaced to resolve the issue. But, in the meantime, dumping air using your jack controller might correct the issue by moving the leveler through some of its stroke, thus getting it to allow air back into the air bag and raise that corner of the coach back up.

[wa8yxm]

What happened? You loaded all your "Travel stuff" and thus loaded it down.. likely about 1.5"
This is easier with a car... Measure the bumper height with the car basically empty. Do this at the rear bumper.. Now open the trunk and set 3 or 4 5 gallon pails of water inside (however many you can fit) and measure the bumper height again.. Now remove the buckets .. carefully (you might put only 4 gallons in)

Each gallon is what about 8.6 pounds so 4 times 4 gallons is a bit over 250 pounds.. Now imagine all the stuff you put in the RV.

[Grit_dog]

You couldn’t raise it back up with the jack and put a couple boards or something under the nearest tire?