Two-Post Safety: Lift Carriages and Arm Restraints


A reoccurring theme for many two-post accidents typically involves user error in one way or another. We see it over and over again, unfortunately, even from trained and experienced mechanics. Now, we know most people do things the right way, but one seemingly small mistake can lead to a lot of trouble. With everyone’s safety in mind, let’s review the basics.

Lift operators need to be vigilant each and every time they load a vehicle. When done correctly, vehicles will be stable and safe when lifted on an above-ground two-post car lift. All too many times, however, lift operator “shortcuts” end up in disaster. For instance, choosing the incorrect adapters; using the wrong lift points; overloading a lift; not positioning the center of gravity midway between the adapters; or lifting from the wrong part of the vehicle, etc. Here’s what every car lift operator needs to know about two-post lift carriages and arm restraints.

The right adapter for the right vehicle
Because two-post lifts directly make contact with the chassis of the vehicle, to ensure safe operation, the lifts feature telescoping arms equipped with specialty adapters. This allows for varied chassis and undercarriage support placement. The adapters pictured below, especially the frame cradle adapters, are essential situational lifting tools that every shop mechanic needs to use in accordance with the vehicle being lifted.

BendPak adapters for vehicle-specific two-post operation

Relative ease-of-use when operating this type of lift does not mean there are no risks or hazards that every professional needs to be aware of. Improper use of two-post lifts can lead to vehicle and property damage, even operator injury or death. It is absolutely critical that the lift adapters are positioned according to the vehicle’s factory-recommended lifting points as described in the VEHICLE LIFTING POINT GUIDE and on the WARNING LABEL that accompanies every lift.

As mentioned at the top of this article, the majority of vehicles fall because of negligence due to improper loading of the lift. Using the lift improperly can cause the vehicle to shift. The contact pads should always be been positioned at the factory recommended lifting points, as illustrated on the WARNING LABEL that accompanies the lift, with the center of gravity midway between adapters.

Vehicle-specific adapters are also essential. Always consult the lift manufacture for any vehicle specific adapters (e.g., frame cradle pads) suitable for your lift model.

Understanding arm restraints
Automatic arm restraints, most often found on newer two-post designs, are there to restrain the arms during normal arm positioning procedures as the operator crawls on the floor and locates the arms on the vehicle chassis. They also prevent operators from bumping into them and shifting them out of position.

Arm restraints are typically a spring-loaded spur and rack gear system. When the lift rests on the ground, a release rod contacts the floor and raises the rack gear away from the arm gear, making it easier to position the arms while lower to the ground. When the lift is raised, the spring-loaded restraints engage the arm gear causing each arm restraint assembly to become activated.

The arm restraints should always be inspected, maintained and adjusted to automatically activate when the lift is elevated, or to instantly engage once the arm starts to move laterally. The arm restraints should ALWAYS be visually checked for proper engagement prior to lifting any vehicle.

Adhere to the safety labels on your lift and owner’s manual

Many people tend to call arm restraints “arm locks” and believe that they are designed to stand firm as a vehicle is falling, which is inaccurate. Arm restraints are not meant to stay fixed in the event a vehicle starts to fall. They are intended to keep arms under the vehicle during normal service. The ANSI/ALI ALCTV-2017 (standard) lateral load-holding requirement for these components is 150 pounds with the arms fully extended. When a vehicle is falling at velocity due to improper loading or positioning on the lift, the arms will be leveraged under extreme load, a load sure to exceed the nationally mandated standard of 150 pounds.

How to apply this knowledge
Every single time you lift a vehicle, look at the point of contact between the vehicle and the lifting pads of your car lift. All pads should be at the vehicle’s manufacturer-recommended lift points. If the vehicle is a unibody chassis design, standard rubber-topped lifting adapters are probably the best option, but when lifting trucks and SUVs, they might not be the best or safest bet. Typical frame-type vehicles such as trucks and SUV’s are often covered with vehicle undercoating. That’s why we highly recommended frame cradle pads that straddle the frame and reduce the chance of the vehicle frame shifting to one side during the lifting procedures or service.

Look at the images of the vehicle below. The cracks near the wheel well at the front and back occurred due to improper operation of a two-post lift.

Arrows indicate side skirt damage due to improper two-post operation

It appears that the contact pads were positioned on the fiberglass side skirts, which are definitely NOT the OEM lifting points. A car lift will never, ever cause that kind of cracking and vehicle chassis damage when used as intended. The kind of damage seen here occurs because the vehicle’s side skirts are not load-bearing.

Why we’re telling you all this
We’re putting this article out there because raising vehicles on a car lift is important for business and home maintenance, and it’s just as important to reflect on one’s own practices. Stay alert and remember that BendPak lifts are very safe when used correctly. As longstanding members of the Automotive Lift Institute, we know car lift safety as well or better than anyone. We can all but guarantee that our lifts will keep you protected, as long as you follow the rules of safe lifting.

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