Electric scissor lifts can be very useful tools on many jobsites, and fortunately, manufacturers have worked hard to produce machines that are highly productive with low maintenance requirements. Still, to get the most life out of your fleet, you need to be diligent about inspecting your machines when they return from a rental.
At first glance
The first step to any inspection should be an evaluation of the general integrity and safety of the machine. This begins with a visual check for any obvious damage such as bent rails, broken handles, missing guardrail pins, loose wheel lug nuts and any leaks. In addition to glancing at the overall machine, closely examine the deck and deploy the extension to see if all is working properly.
The next part of the inspection focuses on the scissor stack. This is the most important part of the machine when it comes to safety and longevity, but it's the hardest part to inspect. To get a good look at the machine, make sure everything is at eye level so it's easier to see problem areas.
While the machine is in the lowered position, look for cracks or rusted areas around the pins and bushings, as well as near the welds where the pins and bushings are mounted. Look for signs of unusual wear, including metal shavings and elongated pins or bushings. Tolerances must be tight and there shouldn't be any unusual gaps.
Many manufacturers are responding to the requests of rental businesses by eliminating excessive greasing on their scissor lift models. As a result, many electric scissor lifts have no grease zerks, but use "dry" bushings instead.
While greasing is largely eliminated, the slide blocks, which attach the base of the scissor lift to its scissor stack, do require regular lubrication.
Following the stack inspection, check for tire integrity. It's important to look for bad gashes or peels since it's not uncommon for tires to become badly damaged during loading and unloading from trailer ramps.
Close to the tires is the pothole protection system. Check to be sure the plates are properly pinned to the chassis and can move freely. Always check the pothole protection system from the ground. Raise and lower the machine with the system deployed to ensure proper operation. Sometimes, if the pothole protection system is actually deployed on a jobsite, the plate can become damaged and will need to be replaced or repaired.
Be sure to check the safety prop or scissor stack locking device. This brace should be used during maintenance to ensure the machine doesn't drop shut during service procedures. Check to be sure the prop is in place and intact before performing any maintenance on the machine.
Now remove the prop and locate the emergency lowering device. Confirm it works by lowering the scissor lift.
The inner workings
When inspecting the working parts of an electric scissor lift, start by checking the hydraulic manifold compartment and look at the hoses and fittings for wear or leaks. Inspect the drive motor cables for frays, cuts and any other obvious damage. Check for leaks in the steering cylinder by looking on the floor of your shop. Leaks will be highly evident on concrete surfaces, but not so easily detectable on asphalt, so be sure to give the area a keen visual inspection.
Also look at the lower control box assembly, paying close attention to the ignition switch. Then check to ensure that the emergency stop switch is operable.
At this point, check the battery compartment and look for any loose connections, low water levels and cracked cases or missing caps.
Don't forget to look at the static strip, the rubber strap that drags along the ground during operation. On models with pale tires, this strap collects static electricity, preventing shocks. This feature is not necessary on models with black tires, as the dye in the rubber kills any static electricity that could otherwise build up when traveling over carpets or other electrically conductive surfaces.