BAC Forum
General Boards => Technical Support => Topic started by: Randy Perry on August 15, 2011, 04:03:13 AM
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Just wondering why (via the red sticker by the leveling switches) that I'm suppose to put the slide out before leveling the coach? My better judgement says to level the coach first, then put the silde out! I must admit, I've been breaking the rules and leveling first, then sliding out!! Can someone s-plain why??
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In a nut shell when you level the coach there is usually some body torquing that occurs which can create problems with the slides. Our owners manual states it's very important to level after the slides are run out. Also just the act of running out the slides, will change the level of the coach, but the primary reason is to prevent slide trouble. We always go back to travel mode before running them in also. That is my understanding on this subject anyway.
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Randy,
Larry is right about the fact that the act of leveling the coach can torque or twist the coach enough to cause damage when extending the slides if they are not extended before leveling. The subject was discussed in a recent thread. http://forum.bacrallies.com/m-1312849050/
Gerald
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I hate to admit it, but even though i run the slides out, then level, I never go to "travel" mode then run them in. I guess I should.
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Yes, you should Robert as the coach frame would still be torqued, plus you ALWAYS want the coach to be at full ride height before bring in the slides.
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Prior to Monaco having problems, I called Tech Support to ask and confirm (in accordance to the manual) the way to operate the slides. He said that the coach is put together with full air bags.
He said:
To Level:
Slides out
Dump Air
Level
To get going:
Air up
Bring up jacks
Bring in Slides
Have not had any problems.
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When you are in Travel Mode the air bags have the coach body square with the frame, and there is no twist in the body at that point, even if you are leaning one way or another due to unlevel ground. That means the slide out rooms are also square all-around with their openings in the body. That is the time to put them out or take them in - when you are in Travel Mode.
If you level the coach on uneven ground, then by definition the leveling action has to twist the body in one way or another. Moving a square slide through a body opening that isn't square ain't a good idea, and something's gonna get strained needlessly. And as Larry said, if you get leveled up and then put out slides, the weight of the extended slides will torque the body and throw off your nice neat level. So you have two very good reasons to burn into your mind the old Monaco adage, "Slides out first and in last".
My wife remembers it better than I do, and catches me on the rare occasion I try to level while I'm still in the driver's seat after parking - an easy thing to do! :X So get your co-pilot to memorize the adage too.
-Joel
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Good explanation Joel, well said
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Thanks everybody..........guess I'd better re-train myself and pay attention to those RED stickers with important instructions :)
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You can still torque the chassis after the slides are out by dumping the air and leveling if your not careful.
Butch
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You can still torque the chassis after the slides are out by dumping the air and leveling if your not careful.
That's basically the issue I reported in my recent post. Is air dumping really necessary? There are always creaks and groans as the chassis drops down; I'm sure those are indicative of the torquing.
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Actually, if the spot your on is not flat when you dump the air, you can still torque the chassis when the suspension bottoms. My coach has the manual hydraulic leveling system with a single leg in front and one behind each rear wheel. If you allow the front of the coach to pivot on the front leg, the chance of torquing the chassis is minimized. Unless I know the spot is perfectly flat, or I need the extra leveling capacity, I don't dump my airbags.
Butch
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I still contend the owner's manual is only written for the standard hydraulic leveling system and not the optional air leveling system. If you have the optional air leveling system, I still contend the best method is to level before sliding the slides out, and to make sure the coach is still level before sliding them in.
I didn't realize that in travel mode the frame could not be in a flexed position. I thought the travel mode was supposed to attempt to keep the body vertical side to side, not front to back. If true, the chassis could be in a flexed position.
Gil
08 Contessa
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Gil,
When the coach is in travel mode, it tries to maintain the proper carrying or standing height (the distance between the axle and the frame) and that has nothing to do with whether or not it is level from side to side or front to rear. If the road surface that the coach is on is sloped 6 degrees, the coach will be 6 degrees off level when it is traveling on that surface.
There is no difference between the time that the slides should be extended and retracted with hydraulic leveling or air leveling. Hydraulic leveling is more rigid than air leveling and because of that it has a strong tendency to torque the coach more than air leveling will. However air leveling will still torque the coach. My coach has both air and hydraulic leveling, and on occasion when air leveled (that I use almost exclusively), my coach will torque so much that if the living room slide were to be retracted without airing-up to travel mode the rear cabinets would scrape the wall and cause considerable damage.
Gerald
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As I stated earlier we have air only leveling and the coach has still torqued the coach enough that I have had trouble opening the storage compartment doors on occasion. As soon as I go back to travel mode they open/close without any trouble. Just confirming what Gerald said.
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Is it necessary or recommended to level when in storage slides in fridge off. or should the coach be left in travel mode?
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I think many coaches have air leveling as the standard, and hydraulic levelers are the option, Gil, since the air is already there to control ride and lean on the road.
As Larry and Gerald indicate, the idea is to have things "square" any time you are moving the slides, and Travel Mode provides square. Just because the body is "level" doesn't mean it's "square".
Here's the deal, Mike: In 2006 I stored my brand new coach by just parking it. Over time some air dissipated since most rigs leak air somewhere, even in miniscule amounts, and it shows up eventually as a lowered corner or side. Because my parking spot had a low spot under the left rear tires, and the ground under the rear axle was several inches lower than under the front, the resulting combination of off-level site and one corner leak (together with a faulty windshield installation at the factory) showed up in the form of a creeping crack in the windshield. After a couple of weeks that became several creeping cracks around the first one.
Whether I had left it in Travel Mode or dumped all the air, or leveled it, I would have still had the same problem because of the micro-leaks over a long period and the uneven ground. The best thing you can do, when storing your rig, is to make sure the ground/pad is as level as possible in all directions.
I corrected that situation, although I still have a 2" fore-to-aft slope; at least there is no corner-to-corner discrepancy. No matter how I leave the air system set, in theory I should be okay. However if one airbag system leaks more than others, a body twist is still almost inevitable. To overcome that, and to provide easy entry of the coach via a fully lowered entry step, I routinely dump all the air after parking for storage. A relatively level coach from the ground up also means you can start the fridge the day before a trip without starting the coach to air up and level. Plus, since things are square, we can work in the coach or give "tours" anytime while stored, and put the slides out and in without worry.
As Larry mentions, checking the squareness of your bay doors is a good way to see if the body has a twist or not. It likely won't have one in Travel Mode, but neither will it likely stay that way while stored over time.
-Joel
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Gil,
When the coach is in travel mode, it tries to maintain the proper carrying or standing height (the distance between the axle and the frame) and that has nothing to do with whether or not it is level from side to side or front to rear. If the road surface that the coach is on is sloped 6 degrees, the coach will be 6 degrees off level when it is traveling on that surface.
There is no difference between the time that the slides should be extended and retracted with hydraulic leveling or air leveling. Hydraulic leveling is more rigid than air leveling and because of that it has a strong tendency to torque the coach more than air leveling will. However air leveling will still torque the coach. My coach has both air and hydraulic leveling, and on occasion when air leveled (that I use almost exclusively), my coach will torque so much that if the living room slide were to be retracted without airing-up to travel mode the rear cabinets would scrape the wall and cause considerable damage.
Gerald
This subject has been noodling in the back of my mind for a while now. I was certain that I had read the same thing Gil mentioned, that with air leveling, you should level first, then slide the slides.
Today I happened to be looking for something else in my document file and came across the HWH Corporation Operators Manual, HWH Hydraulic Spacemaker Room Extension System manual. In this manual are the official operating procedures from the factory that made the slides.
They say in Room Extend Procedure:
"IMPORTANT: Do not operate the room extension unless the vehicle is at the proper ride height and the leveling jacks are retracted. If the vehicle is equipped with HWH air leveling, the vehicle should be level before operating the room."
They say in Room Retract Procedure:
"IMPORTANT: Do not operate the room extension unless the vehicle is at the proper ride height and the leveling jacks are retracted. If the vehicle is equipped with HWH air leveling, the vehicle should be level before operating the room."
I understand those quotes from the manual to mean I should level my coach prior to sliding out the slides because I have air leveling. Am I reading them wrong?
Ken
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Monaco disagrees with the HWH manual, and I for one think Monaco's concept is more sensible in our coaches, for the reasons already brought up in this thread. When in travel mode, the opening and the slide room are "square" with one another. That is not necessarily the case after leveling, when the axles and the body may be no longer equidistant from one another at all corners, as per Gerald's point.
Joel
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Ditto to what Larry says in confirming Gerald's statement. We have both hydraulic and air. I always use the air and getting to travel mode is critical.
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CAROL, HERE, NOT KEITH! :)
This whole subject is so confusing.
Our 98 Patriot did not come with the red warning sticker that we have seen in so many other coaches.
When we bought it, we were innocent neewbies and didn't know any better. So, we always dumped, leveled and extended/retracted, un-leveled and started coach. This has always worked wonderfully for us. After discovering our supposed mistake we tried to conform, albeit half heartedly because it didn't (and still doesn't) make sense to us.
For instance: A few weeks ago we were in Tillamook OR. We pulled into our spot and were unlevel to the co-pilot side. We were going to do this right so we put the slide out first. It did come out, but not before getting hung up on the upper left (from the outside) corner a goodly amount before "popping" out. There also seemed to be a "clunk"ing noise from the bottom of the slide. This is not the first time this has happened in this scenerio, either. I do not like this. All seemed well, tho, so we dumped and leveled.
When we left a few days later, after adjusting the level several times due to soft ground, we went back to the old way and retracted the slide, then the jacks and started the coach. NO PROBLEMS. You can see our confusion. What do you guys think of this? I am dying to know! :-/ :)
Thank you!
Carol Moffett
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Monaco disagrees with the HWH manual, and I for one think Monaco's concept is more sensible in our coaches, for the reasons already brought up in this thread. When in travel mode, the opening and the slide room are "square" with one another. That is not necessarily the case after leveling, when the axles and the body may be no longer equidistant from one another at all corners, as per Gerald's point.
Joel
Joel, I'm trying to get my brain around why the axle position is important. If my "box" (the motorhome body built on top of the frame) is square and level it shouldn't matter where the axles are. In it's simplist terms, my slideouts are boxes sliding out of another box. If I have leveled my big box, that is, all corners are level with each other, then my little boxes should slide out squarely. Remembering of course that I am talking about air leveling and all four corners are supported.
If I have a tripod leveling system then the end with only one support could conceivably twist. This is why it may be important to put the slides out while on all six/ten tires.
Here's my practical test. Take an ordinary cracker box, the kind with 4 sleeves of crackers inside. Take the crackers out and close up the end again. Resemble a motorhome? Set it flat on the counter and sight down the sides. Flat, right? Now put it on four equal height blocks and sight down the sides. Flat, right? Now take one block out of one end and put the remaining support block in the middle, like a tripod leveling system. Then put some pressure on one unsupported corner and look at the side of the box. See how the surface isn't flat anymore? There is you slide binding. Now go back to four corner support and put the same weight on the corner. The side is flat again isn't it.
OK, now suppose all four corners weren't on the counter anymore, one corner is hanging over the edge. If you put a longer block (maybe it looks like a stick now) under that corner to support the corner level with the other three then the box is still level, square and the side is still flat. Imagine that your air suspension had that much travel and it doesn't really matter where the axles are, what matters is that the big box is square and level.
I would very much like someone to explain how level isn't also square. If my coach is level fore and aft and side to side, how can that not also be square? Of course that assumes no manufacturing defect or damage.
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I'm not sure how else to put this, but just because your box is level does not mean it is square, and consequently does not mean any openings in the box are square. Perhaps you are presuming that your slideout box, a seperately framed entity, would conform to its opening in the body regardless of any twist caused by forcing the body away from the congruous relationship it had with the chassis in Travel Mode.
Your cracker box is setting on a flat counter. Open it at both ends and put it on a very slightly uneven surface instead (a placemat under one corner say), like a campsite might be, then press on the box edge with one hand while holding a small level across on top with the other until it reads level. Does it look square to you? Another previously mentioned test: park the coach on a surface with one tire or tire pair in a very low spot, or drive one corner onto a 2"-4" block. Now level the coach. Are your bay doors all square in their openings?
Your "box" may be relatively square if one end or one side is evenly low, and you level up, but not if one corner is off kilter. Parking the coach on ground where one coach corner is lower than the others, and then taking it out of Travel Mode and leveling it, puts a twist in the body. The seperately framed slideout room does not congruantly twist with it, no more than a bay door will. Like the bay door, the slide room is "fastened" to the coach on only one of its 4 sides. Moving the slide in this configuration is putting a rectangular peg through an oblique hole whose opposing sides are perpendicular but whose corners are no longer right angles.
I dunno, Gerald. Care to take another shot at picturing it for Ken?
Joel
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I guess I missed too many geometry classes.
Since my motorhome IS a box, I'm not sure how opening the ends and squishing the top flat proves your point. To my knowledge all coaches level from the bottom. Air leveling uses the tires as four independantly movable legs to level the coach (assuming a six tired coach) Air leveling doesn't try to push down on the high corner, it raises the other corners, with the legs/tires to make the floor level or lets air out of the high corner to make the coach level. Likewise if one tire is in a depression, it will raise the suspension on that tire and lower the suspension on the other three to level the floor. If the floor of the box is level in two directions, there is nothing forcing it out of square.
Ken
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It's not the floor that's out of square; it's the walls. In the simplest circumstance, if one corner is low, air leveling will push up on that corner until the roof and floor of the box are level. But then the walls won't be square, and that's what counts for your slide out.
For more perspectives, review this discussion, especially the input by Diplomat Don: http://www.irv2.com/forums/f115/sliders-in-or-out-before-leveling-49723.html
Joel
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Maybe I could explain this by pointing out that the levelling system works to get a single point control level. I'm not sure where it is on my Marquis, I know on my 90 Grand it was between the water heater and the cooktop. The designer hoped that the cabinet frame would be square with the rest of the coach. This dream also didn't allow for the body twisting.
Meanwhile, in travel mode, there are four points being measured (one at each air bag) so the overall effect ends up being more square.
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OK, so Diplomat Don says: "Once you drop the air out and then start twisting the frame to make the coach level, you are tweaking the openings.
One other point that didn't get mentioned is that the front jack should ALWAYS be put down first and make contact with the ground. "
So he's using a jack system and a tripod so it's not at all applicable to my particular coach. HWH's manual confirms that with tripod you should put the slides out first, there's been no dissent on that.
Second point is that I keep hearing about twisting the frame to make the floor level. The airbags on my coach are between the axle and the frame/coach body. (RR10 chassis) When the system senses that a corner is low it actually pushes the frame BACK into square and level. I'm going to go over and double check, but I believe that the floor and the frame are on the same plane. When the floor is level the frame rails are also. I think I'll find that the floor supports are bolted directly to the frame, making it impossible to have a level floor and a twisted frame.
I'm still trying to imagine how the floor and ceiling can be level and square with each other and the walls be out of square. When I think back to Joels explanation of a placemat under a corner, then the floor isn't level so any effect it had would not be applicable. The box could be pushed at the top to keep the floor and ceiling parallel but the side or end trapazoid, but the motorhome has no such forces to cause that when parked. The coach has shear strength built into the walls, ends and bulkheads to prevent that movement when moving, stopping and turning corners.
I guess that I'll suggest we agree to disagree. First hand reports from at least 3 of us and the manufacturer of the slidouts and leveling system think that leveling before sliding out is, if not the correct way for all, at least a very workable solution. It also works very well for hooking up utilities, no slideouts over the compartments. For not disturbing other campers by starting and stopping the engine. One simply backs or pulls in, levels, turns off engine, hooks up utilities as needed, slides out, cold beer.
Thanks for the conversation,
Ken
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Hi Ken,
I absolutely agree. Air levelling will uniformally support the coach .
Arrive,level , switch off and slides out.
Leaving,engine on,check level,engine off,slides in,engine on,depart.
This works for us.We learned the hard way using the jacks and bust a windshield. I dont use the jacks any more.
jeremy
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[quote author=]Maybe I could explain this by pointing out that the levelling system works to get a single point control level. I'm not sure where it is on my Marquis, I know on my 90 Grand it was between the water heater and the cooktop. The designer hoped that the cabinet frame would be square with the rest of the coach. This dream also didn't allow for the body twisting.
Meanwhile, in travel mode, there are four points being measured (one at each air bag) so the overall effect ends up being more square. [/quote]
All coaches have different systems. I find on mine that there are 2 leveling sensors, one forward and one aft. In travel mode there are 3 sensors, one in front and one on each side in the rear.
As an interesting aside, HWH has a technician training program available on-line at http://www.hwhcorp.com/ It explains in pretty good detail how the systems work.
Ken
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The owner's manual for my coach clearly states that the rear jacks should be put down first and the coached leveled side to side before putting down the front jack.
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The owner's manual for my coach clearly states that the rear jacks should be put down first and the coached leveled side to side before putting down the front jack.
Yep, same here.
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One could envision that the normal ride suspension leveling valves being a single design in the front will reach a compromise position without putting any twisting forces on the frame given it will add or subtract air from the four front airsprings uniformly. The rear leveling valves will attempt to offset some amount of side tilt but they are limited in how much compensation they can achieve, especially on the front of the coach, given they are acting on just the rear axle air springs which are all out board. So the coach is fairly uniformly resting on 8 or 10 air springs.
My guess is that the designers felt that the maximum amount of frame twist that could be created was less for the ride suspension leveling valve system due to its configuration than either the full air leveling system or the hydraulic system which has more range of movement and therefor the ability to put more force on one quadrant of the coach frame vs another.
I think it is range of motion for each system that you have to think about and the worst torque on the frame comes when corners are at the extremes of lift and fall range.
The aired up ride suspension I believe would have less range of movement. It is really not about whether you are level or not, it is about how much force and twist was put on the frame to achieve level. Did the required leveling forces distort the slide openings?
I thinco Monaco says aired up resting on 8 or 10 airbags within the range of the over the road leveling system should have limited frame twist enough that the slides will work properly. Most all the problems with body torque seems to occur in the front with windshields popping and large slides rubbing. The front over the road air leveling system does not compensate for side to side offeset at all by design. I'm not the designer but this makes sense to me so I always let the slides out before I dump air and level and always air up before I bring them in.
Later Ed
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The owner's manual for my coach clearly states that the rear jacks should be put down first and the coached leveled side to side before putting down the front jack.
Just to clarify, the quote to always put the front jack down first is from Diplomat Don, not me. I quoted it exactly as written with a space between paragraphs.
Ken