Levelers, stabilizers, leveling jacks, scissor jacks, chocks, there are almost as many names for devices that level and stabilize as there are products available. However, these products play an important part in not only leveling and stabilizing your rig but also helping with structural integrity and proper appliance performance!
Most RV owners are familiar with leveling jacks and there are have been several brands over the years. HWH and Power Gear were the big names in hydraulic leveling jacks in the 1990s and 2000s and were powerful enough to lift the tires off the ground of a 22,000 lb diesel pusher.
Lippert Components Inc (LCI) has purchased Power Gear as well as several lighter weight leveling jack providers such as Kwikee that had an electric system and have several of their own LCI brands. The important thing to remember about whatever type of leveling jack you have or are going to install is that they are doing more than just leveling your rig for a comfortable night’s sleep.
In my early days at Winnebago, we tested chassis’, welded foundations, and finished motorhomes on sine wave test tracks as well as computerized pads to determine what type of stress would be applied to various components in an unlevel situation or excess road vibration. At the time we were testing various slide room mechanisms and did over 14,000 extensions and retractions and what we found was in an unlevel condition, not only does the chassis/floor twists but the sidewall does as well and the room has resistance and eventually had created issues with operation. With that, all units with a slide room had leveling jacks as standard equipment.
Back when HWH was “THE” hydraulic leveling jack provider they designed a joystick extension and retraction pad that would only allow a bilateral extension procedure. The photo above is from a 2003 Winnebago Brave and you can see the top and bottom levers would control the front and back jacks. You would push those from center to activate and the center lever extended and retract the jacks in the direction you pushed the lever and it would always extend two jacks in a bilateral direction only. This meant if you pushed the lever forward, the two front jacks would extend, down meant the two back jacks would extend, and side to side following suit. This was designed to reduce the stress of extending one jack on an uneven spot and twisting the chassis. The system also had a pressure-sensitive feature so as you extended the two jacks in whatever direction, they both would come down and if one hit the ground before the other, it would pause until the other hit the ground and raise the coach evenly. This eliminated any twisting in the chassis and ultimately in the sidewall, slide rooms, and other areas of structural importance.
While developing a training program, we put one front tire of a standard chassis on a 12” car ramp to show the twist that occurs on a chassis. We saw that the compartment doors and entrance doors popped open. Yes, this is extreme however imagine what just a slight unlevel condition of 3-4” would do in a campground to the structure of your rig! I have gotten numerous photos of rigs that have the sidewall material shifted from the trim over the years.
So the importance of leveling is keeping the structural integrity of the chassis, flooring, and sidewall in a level plane which will allow the slide rooms to operate without stress and limit the stress on the sidewall to roof structure as well.
One last note on leveling the rig, your absorption refrigerator needs to be level to allow the coolant solution to flow back down to the boiler assembly through the zig-zag tubing. We have covered that many times before.
Even after all that work of leveling your rig, it might not be stable which means a rock and roll situation that is much more than just annoying! Tires are inflated with air to provide a smooth cushion while driving but are not meant for providing stability when stationary. The four-point leveling jacks do provide superior stabilization, however, most of the other systems could use some assistance. For instance, if you have scissor jacks, they help level smaller rigs and keep them from tipping front to back but provide poor stabilization.
In fact, without additional support and wheel chocking, these can be damaged easily. Most trailer owners add some type of leg support for stability or even wheel stabilizers.
5th wheels pose a larger problem with the long overhead in the front that can get a little spongy and even cause some issues with structural integrity.
These are photos of a unit that has shifted considerably and now has very expensive repairs needed. It’s best to level and stabilize the rig and many 5th wheel owners also add support to the kingpin with a tripod support.
Some even add some additional side-to-side support for the larger rigs.
In addition, every technical support rep and engineer that I have talked with recommends leveling and stabilizing the rig before extending and retracting the slide room. If the rig is out of level and not stabilized, the chassis will shift, the floor will twist, and the sidewall will twist meaning you are trying to extend a square room in a twisted hole and will have resistance.
About the author: Dave Solberg: Managing Editor, RV Repair Club
For the last 25 years, Dave has conducted RV maintenance and safety seminars, developed dealer and owner training programs, written RV safety and handyman articles, authored an RV handbook reference guide and logged over 100,000 miles on the road in an RV.
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