Reprinted with permission of PTEN, May 1994
There is no doubt, a lift will improve productivity. Shop owners have reported productivity increases of up to 30-percent from stalls with lifts compared to stalls without lifts. Correctly selecting, installing and maintaining a lift will ensure years of trouble free service; ensuring consistent productivity from the repair stall.
Selecting the right lift for your shop involves more than looking at just capacity and price. Different designs and product features can make a lift easier or safer to use, more durable, or more appropriate for certain types of repair tasks.
Lifts can be in-ground or above ground, and, for the above-ground types, stationary or portable. They can be frame-engaging, axle-engaging, rocker-panel (pad) lifts, or runway lifts.
Lifts can be operated using hydraulic, mechanical, electric, compressed air, or some combination of these power sources. In-ground units are often either all-hydraulic or a combination of air and hydraulic power. Above-ground lifts are typically powered by a combination of electric and hydraulic power.
Today’s lift technology is relatively simple. There are no significant differences on lifting speed or energy use between in-ground and above-ground versions having the same capacity.
In-ground versus above-ground
A shop 101-ft long can comfortably fit nine in-ground lifts in a bay area that would permit only eight above-ground units. In addition to the space bonus, in-ground lifts have fewer moving parts, and for that reason are said to require less service.
In-ground lifts are more costly to install because you must dig an excavation pit. If anything does go wrong, in-ground lifts are also more costly and time-consuming to service, if you must cut the concrete floor and dig to get to the working parts. To cut service and repair cost, newer systems put many connections and working parts near the surface and under access covers that make it unnecessary to break up the concrete floor.
Potential ground and ground water contamination has caused some environmental concern about possible leakage of hydraulic fluid into the soil around in-ground lifts. Lifts do not fall under the Underground Storage Tank (UST) regulations however, as they contain less than 110 gallons of fluid. This would preclude the need for a UST permit. However, soil and water clean-up costs can be enormous, requiring that the potential for any soil or water contamination be addressed.
New fiberglass linings provide cathodic protection to reduce the possibility of electrolysis or bacteriological corrosion causing leaks in the system. At least one major manufacturer is also enclosing its in-ground lift in a polyethylene secondary containment system that prevents any leakage from reaching surrounding soil. Additionally, there is now available a new, biodegradable hydraulic fluid that is environmentally safe, so even if leaks do occur, it is not harmful.
Above-ground lifts can easily be moved. That makes them preferred for facilities in which the shop layout may need to be rearranged for future growth, or where equipment may need to be relocated if the shop lease is not renewed.
According to several manufacturers, about 75- to 90-percent of all lifts sold are of two-post, above-ground configuration.
Low-rise, portable lifts
All of the machinery of a portable or low-rise lift is typically under the car, so technicians have full access all around the vehicle with no obstructions from posts.
Low-rise lifts raise the vehicle only a couple of feet off the ground, making them perfect for collision repair shops, tire stores, and brake shops. Height can be set just where the technician needs it in order to work on wheels or brakes without having to stoop or kneel, and for the painter or metal man to easily reach lower body panels. The productivity gains and work quality benefits are obvious.
Several of these lifts are equipped with wheels and can be moved around the shop and even outdoors in nice weather, offering an “extra bay” when needed. Some models can by used to carry a vehicle from one step to the next in the repair process.
Units are available that can be operated by shop air, with no electricity or hydraulic fluid required. They are ideal for use near or inside the paint booth, where you don’t want potential spark sources such as an electric lift motor.
With air lifts there is no hydraulic oil leakage to get in the paint finish and cause fisheye or other defects, or to spill on the floor and cause slips and falls.
Determination of lifting capacity needs is very important and should be thoroughly thought out before a purchase is made. Here’s one example to consider:
A utility truck with an 8,000-lb loaded weight needs a lift with an 11,000-lb capacity. Here’s why: Each lift arm can handle only one-fourth of the lift’s maximum capacity. If the truck has its weight distributed with 2,500 lbs. in the front and 5,500 lbs. in the rear, the heavier load on the two rear arms will determine the proper lift capacity. Each arm must be able to hand one-half of the 5,500 lbs., or 2,750 lbs. Since each arm is designed to handle an equal amount of weight, the needed lift capacity is 2,750 multiplied by four, or 11,000 lbs. total weight.
Take the time to determine your shops present and future work load before you place the order.
Floor, ceiling space
Most two-post lifts sold are “clear-floor” lifts. There is no base plate under which hydraulic lines, chains, or cables run to connect the two posts. The benefit is no floor obstructions – the technician has free movement of equipment, jacks, and tool chests while working under the car.
With clear floor lifts, any chains, cables or hydraulic lines are run overhead to connect the two columns. Make sure that the height of the overhead lines does not exceed the ceiling clearance in that part of your building where the lift will be placed. Some lifts have adjustable height overhead lines, so you can get the height you need for fully raising tall vehicles without bumping the lift’s overhead lines.
The advent of an asymmetrical two-post surface lift design is probably one of two major design incorporations considered by purchasers and users of lifts today. The second is “clear-floor” mentioned above.
An asymmetrical design allows technicians to open passenger car doors fully without banging them on the lift columns, increasing interior access and reducing vehicle damage. The lift columns are rotated 30-degrees, allowing the short and long off-center arms to position the car far enough back from the columns that the doors cannot hit them.
But the asymmetrical lift that is perfect for passenger cars may not be right for other vehicle types. For example, some full-size vans may be so long that technicians cannot position the van doors away from the columns and still place the vehicle’s center of gravity properly on the lift. On a symmetrical lift, technicians can position full-size vans so the doors are ahead of the columns, preventing the doors from hitting when opened.
Carriages and columns
The carriage raises or lowers the lift arms. Depending on design, it rides up and down inside the column on steel roller bearings, or plastic slide blocks.
Metal roller bearings create less friction than do sliding plastic or teflon-type blocks. Low friction creates less strain on the pump and motor, offering longer life. As a rule, in order to use metal rollers and bearings, lifts tend to be designed with stronger columns.
Greater steel thickness gives greater column strength. Heavier actual weight – not shipping weight – of the lift gives an indication of the amount of steel in the columns.
Because the weight of a car or truck many times is not balanced from side-to-side, the load on each side of the lift is not equal. Lifts are designed to equalize, or synchronize, the lifting speed of one side to the other to prevent falls. Manufacturers use three primary methods to equalize lifting rates.
One method uses cables to connect the two cylinders so that mechanical and hydraulic pressure combine to raise the two sides at the same rate. Another method uses a “hydraulic fluid displacement system” that regulates hydraulic pressure between the two different sized cylinders to equalize lifting speed. A third combines a single, higher-capacity cylinder on one side with stronger, elevator-style cable to pull the slave side arms up along with the power side cylinder. Each system requires some routine inspections and maintenance to keep the proper balance from side to side.
Some cables are made thicker and nylon-coated, to reduce potential for stretching or fraying. Hydraulic systems must be checked periodically for leaks. A chain or direct-drive system, more prevalent among lifts rated over 9,000 lbs., is designed to handle heavier loads with less likelihood of the problems that cable and hydraulic systems may suffer.
Regardless of the design, all require routine inspection and service, and occasionally some repair.
All lifts should have mechanical safety locks to prevent the vehicle from coming down unexpectedly. Hydraulic safety backup systems lock up when they sense any imbalance in pressure between the two sides of the lift. Some lifts also have safeties that lock when any slack or break is detected in a chain or cable.
Most major lift makers have some sort of locking device on their swing arms, as well. Locks prevent the arms from shifting out of position when the vehicle is in the air. Many arm restraints lock automatically as the lift rises. Locks that must be manually engaged and released increase the chance that technicians who find them inconvenient will ignore or disable them.
Some lifts have carriage release points on each side of the lift, making the technician walk around or under the lift to unlock it before lowering. Others have single point release, so the technician can lower the lift while standing in one position.
Three different vehicle contact pad styles are available: flip-up, screw-in, and stackable pads. Screw-in adapters are infinitely adjustable. Flip-up pads adjust easily to several fixed heights, but have less surface area in contact with the vehicle. Stackable pads allow the lowest possible drive-over arm clearance, and can be stacked as high as needed to reach contact points on high-frame vehicles.
Any shop that works on high-frame vehicles such as 4X4’s, Bronco II’s, Ford Explorers, mini-vans, and Toyota 4-Runners should have the full set of adapters.
In some installations additional electrical service capacity may be needed. Most regions will require a permit and that a licensed electrical contractor install the service from the main circuit box to the lift.
Some companies prefer to install 230v 3-phase power to the lifts as power costs will be less over time. This involves installing the electrical service from the pole if not presently installed. In any event, an inspection of the electrical system will be required.
At times, some concrete work may be required, and occasionally some repositioning of overhead lights, exhaust systems or air and hydraulic dispensing systems is needed to make room for the columns and overhead connections.
Warranty; purchase price
How long is the warranty period: Does it cover everything, including the cylinder and power unit? Does the manufacturer and, more importantly, the selling distributor have a good reputation for reliability? Check the length of time it takes to get back in service if there is an equipment problem.
Look for a company that provides a good level of training for equipment it sells. You can get this information by talking to other shops who have purchased the model you are interested in. Ask if the training was adequate, and whether there have been problems, either with the equipment or the service from the seller.
When it comes to price, most suppliers of lifts generally agree: a larger quantity of lifts purchased at one time will, in some cases, benefit the purchaser. All agree that lift pricing is very competitive. In most cases it’s the installation difficulties that will be encountered, and the purchase terms, i.e. cash, lease, open-account, that effect the ultimate price.