Technician Note
Both electric and hydraulic systems depend on the same two things to work reliably: good 12V power and solid electrical connections. Before any other maintenance, those two things need to be right. A leveling system that's acting up is often a power or connection problem — not a jack or pump problem. Check the simple stuff first.
Applies to All Systems
Power, Connections & Physical Condition
Regardless of whether your system is electric or hydraulic, these checks apply every season and before any extended trip. A system that's mechanically fine but has a corroded connector or a weak battery will behave like a system with a serious fault.
- Verify battery condition and charge — the leveling system is one of the heaviest 12V loads on the coach; a marginal battery causes slow operation, error codes, and incomplete cycles
- Inspect all accessible wiring connections at the controller, junction points, and jack motors for corrosion, looseness, or heat damage
- Clean corroded terminals with a wire brush or terminal cleaner and apply dielectric grease to slow future corrosion
- Visually inspect each jack for physical damage before operating — bent legs, cracked welds, or deformed pads should be addressed before the system is used
- Clear mud, debris, and road grime from jack legs and travel mechanisms — debris causes binding, accelerates wear, and can prevent full retraction
- Check that all jack pads are present, undamaged, and seated correctly
- Never operate a jack you can see is physically damaged — the load it's carrying makes a compromised component a safety risk
Make It a Habit — Retract and Home Before You Leave
Get into the routine of fully retracting all jacks and running a retract hold — keeping the retract command held for several seconds after the jacks stop — every time before you disconnect or move the coach. This re-establishes a known starting point for the system and prevents positional drift that causes auto-level errors over time. On fifth wheels, always hitch to the truck first before retracting the landing legs — this removes the load from the legs before they move.
Electric Jack Systems
Motors, Legs & Connections
Electric leveling systems use individual motors at each jack to extend and retract. The motor, gearbox, and screw mechanism are the key components. These systems are generally lower maintenance than hydraulic — but the electrical side needs attention, and the jack legs need to stay clean and properly lubricated to move freely.
- Inspect the jack leg surface for rust, scoring, or corrosion — surface rust can be cleaned and treated; deep pitting or scoring means the leg needs closer evaluation
- Lubricate the exposed jack leg with a dry lubricant — do not use wet grease or oil, which collects dirt and grit and accelerates wear on the seals and mechanism
- Check the motor mounting fasteners at each jack — vibration from travel loosens them over time
- Inspect the wiring harness at each motor for chafing against the frame or jack mechanism during travel
- Operate all jacks through a full extend and retract cycle at the start of each season — watch and listen for anything that sounds or feels different from normal
- If a jack extends or retracts noticeably slower than the others, check its power supply connection before assuming a motor problem
- Do not force a jack that's binding or moving unevenly — diagnose the cause before continuing operation
Hydraulic Jack Systems
Fluid, Seals & Leak Inspection
Hydraulic systems use a central pump, fluid reservoir, and cylinders to extend and retract the jacks. They're powerful and capable of moving heavy loads — but they require fluid maintenance and seal inspection that electric systems don't. Catching a small leak early is far less expensive than dealing with a blown seal or a failed cylinder.
- Check the hydraulic fluid level in the reservoir at least once per season and before any long trip — low fluid causes slow operation, erratic movement, and pump damage
- Use only the fluid type specified for your system — mixing fluid types or using the wrong spec can damage seals and pump components
- Inspect each cylinder for "sweating" — a thin film of fluid on the cylinder shaft is an early warning of seal wear before it becomes a full leak
- Check all visible hydraulic hoses for cracking, chafing, or wet spots — a weeping hose will eventually fail under pressure
- Look at the ground beneath the coach after the system has been operated — any fluid on the ground means a leak that needs to be located and addressed
- Inspect hose fittings and connections for seepage — fittings can work loose over time with vibration
- Keep the area around the pump and reservoir clean — accumulated grime makes it harder to spot new leaks
- A jack that slowly retracts on its own while parked is a sign of a leaking cylinder or valve — do not ignore it
- Hydraulic system repairs — pump, valves, cylinders, and lines — are shop work; do not attempt to open pressurized components
Sweating Jacks Are a Warning — Not a Minor Issue
A cylinder that looks damp or shows a light film of fluid is telling you the seal is starting to go. Address it before it becomes a full leak. A weeping seal that gets ignored will eventually fail — often when the system is under load. A blown seal means fluid loss, a jack that won't hold position, and a coach that can drop unexpectedly. Catch it early while it's still a seal replacement rather than a cylinder replacement.
Fifth Wheel Landing Legs
The Gear Drive and Screw Need Attention
Fifth wheel landing legs are a different mechanism from travel trailer leveling jacks. They use a gear drive and a long threaded screw inside the leg to raise and lower the trailer. That screw is what most people neglect — and when it runs dry, it wears slowly, gets noisy, and eventually seizes or strips the collar nut it threads through. Replacement is expensive. Maintenance is not.
The factory does not always apply sufficient grease to the drive screw from the start. If you've never serviced the landing legs on a used fifth wheel, treat it as overdue.
- Extend the legs fully and inspect the exposed leg surfaces for rust, damage, or signs of wear
- Lubricate the exposed screw and leg surface — white lithium grease on the gear components; silicone spray on the exterior leg surfaces
- Do not use petroleum-based grease on hydraulic landing gear — it damages rubber seals
- Locate and lubricate any zerk fittings on the gearbox — not all legs have them, and on some they are difficult to find; check both sides and the top of the leg housing
- Check the bevel gears at the top of each leg where the drive shaft connects — apply a small amount of grease and work it in by cycling the legs
- Inspect the cross-member that connects lead and follow legs for looseness or damage
- Do not over-retract the legs — many have a maximum retraction point; going past it can bend the inner leg or damage the mechanism
- A grinding or growling noise from the landing legs is a warning that the drive screw is running dry or the gears are worn — don't ignore it
Pre-Season Checklist
Before the First Trip of the Year
- Check battery condition and charge — load test if the battery is more than 3 years old
- Inspect all accessible wiring and connections — clean and treat any corrosion found
- Clean all jack legs and remove accumulated debris from the previous season
- Check hydraulic fluid level (hydraulic systems)
- Inspect all cylinders and hoses for sweating or weeping (hydraulic systems)
- Lubricate electric jack legs with dry lubricant
- Service fifth wheel landing leg screws and gearbox (fifth wheels)
- Run a full extend and retract cycle on all jacks — watch and listen
- Verify the control panel functions correctly and all indicators are normal
- Confirm jack pads are in good condition and properly seated
The Most Important Rule
A leveling system that's well maintained and properly homed before each trip will give you years of reliable service. The problems that end up in the shop are almost always from deferred maintenance, ignored early warnings, or a system that was never given a proper starting point. The retract-and-hold habit before every departure takes thirty seconds and prevents more problems than any other single thing you can do.