The Evolution of Bus Lifts

A walk down memory lane takes us out of the pits and up to computers

Denny Coughlin | Contributor

Replacing an over-the-axle pipe on a creeper is not an easy task. It is much easier to have the school bus six feet in the air allowing technicians to walk beneath the bus and easily slide the tail pipe over the axle without any twisting or forcing it into place. This has been an evolutionary process to get to the easy way of life.

In the early years, shops were built with a service pit. If you are unfamiliar with the concept, picture long, narrow pits built directly into the floor where the mechanics could walk under the bus to service them. The pits were about 3 feet wide and four or five feet deep, and they included a wider area in front of the vehicle with steps for access. The bus or truck would be driven over the pit allowing access to the full length of the underside of the vehicle. This was very economical in that, after it was constructed, it was maintenance free. There are reasons pits are no longer constructed or, in many cases, even allowed in today’s school bus garages. Many hazards were inherent to the system. Since it was below ground, fumes could accumulate in the pit. A spark from an electrical connection or from the use of a torch could ignite a flash fire. In the event of a fire, the obvious way out was to escape up the steps at the front of the vehicle. Not always possible if you are trapped at the rear during a fire. Regulations also require all lights to be protected and shielded. Modern day pits commonly used by some automotive oil change service chains.

The next step in the evolution was the in-ground lift. For smaller vehicles, many were air-pressure operated, single-post lifts with four arms extending to the lift points of the vehicle. For larger trucks and buses, two lift cylinders were required, one at the front axle and one at the rear axle. Due to the larger weights encountered, these cylinders were hydraulically operated. The different wheel base lengths required that one of the posts be moveable. These worked well for all types of work, but they were permanently installed and expensive.

The demand grew for a more versatile lift system that was easier to install and that could be removed easily. This niche was filled with the drive-on, above-ground lift. It was constructed around a heavy metal frame that lifted the drive-on ramps, usually with a cable system. While this system works well for oil changes and exhaust work, changing wheels and brake work is not conveniently performed.

The industry required more versatility, and the four independent post lift emerged. These are four moveable and portable electric lifts that can be used on any flat shop floor. The lifts can be rolled from one area to another as needed. While this is a convenient way to get the vehicle in the air for service, lifting by the wheels (again) limits the type of work that can be performed. These lifts adapt easily to a fleet with a large variety of vehicles.

The most modern in-ground two-post lift is extremely automated. They are computerized and assure the lifting process remains level, within about 3 inches when lifting and lowering. The cost of the lift and installation requires long-term planning and evaluation.

We are always looking at the feasibility of a lift system. The first consideration is to look at the facility. Are you going to be in this maintenance shop for a long time, or is it temporary? This may determine if you want to consider a permanent or a portable type lift. Do you have a ceiling with 6 feet of clearance above the bus roof? Do you have electrical power servicing the building that can accommodate the demands of the lifting system? The service bays may need to be longer if working on both front engine and rear engine buses, since the rear axle is positioned further back on a rear engine bus.

The pay-back on the investment is a serious consideration. A lifting system that costs from $15,000 to $85,000 requires careful analysis. If you are going to be in a facility for many years, take the cost of the lift and divide it by the expected life of the lift. This is somewhere around 15 to 20 years. To get a more accurate analysis, calculate how many hours per year the lift will be utilized. You can easily calculate the depreciation per hour for the life of the lift. Evaluate with your maintenance crew how much more efficient they will perform with the ability to raise the vehicle in the air to do the service and maintenance work.

I believe you will be surprised at the payback you will receive from this rather large capital investment.

Coughlin is the fleet operations manager for Minneapolis Public Schools. He can be contacted at Denny.Coughlin@mpls.k12.mn.us.