Courtesy
of
Mohawk
42 | September/October 2014
Twin-post lifts
Safety and maintenance tips
Compiled by Mike Mavrigian
I
n this article, we'll address safety and
convenience options specifcally for
commonly used twin-post lifts, with
two primary focus points: shop safety and
increased effciency.
Information sources
The primary source for lift inspection,
proper operation, lifting procedures, and
annual training is the Automotive Lift
Institute or ALI (www.autolift.org), an
association of vehicle lift manufacturers.
Lifting procedures vary depending upon the
lift type being used.
Lifting points
When the lift is set correctly, and prior to
a technician servicing the vehicle while on
the lift, the weight of the vehicle should
be maintained by the mechanical safety
locks, rather than by hydraulic pressure.
The hydraulic system should be used only
for lifting and lowering, and not for vehicle
support during service.
A two-post lift engages the vehicle frame
or lifting points. It is absolutely critical
that lift operators are able to reference the
specifc lifting points for every vehicle that
is to be raised on a lift.
To help shop technicians determine
manufacturer-specifc lift points, lift manu-
facturers who are ALI members include a
copy of the book Lifting Point Guide (LPG)
with every lift they ship.
However, the book is updated each year,
so it's imperative that shop owners pur-
chase a new, updated copy of the lifting
guide annually. The guide covers 20 years of
vehicle lift points. A fve-year-old version
of the guide is missing information on the
last fve years of vehicles. If you don't have
the current guide, you'll end up playing
guessing games with regard to lift points.
Choosing the wrong lift points can pose a
real safety risk, along with potential under-
carriage damage.
Consider vehicle weight
Another critical issue to consider is the
weight of the vehicle and the capacity of
the lift. Every brand of two-post lifts has
four telescoping swing arms that actually
support the vehicle. So, it's vital to know
the per-arm capacity (determined by divid-
ing the total capacity of the lift by the
four swing arms) so the arms will never be
overloaded.
Let's use the example of a one-ton work
truck with a standard load of tool boxes
or service equipment. The lift we have is a
10,000-lb. capacity lift, meaning a maxi-
mum load of 2,500 lbs. per swing arm is the
most we should try to lift. The truck we use
in this example might only weigh 9,000 lbs.
However, after putting the truck on a scale,
we determine the rear axle has a weight of
6,000 lbs., while the front axle has a weight
of 3,000 lbs. This means our 9,000-lb. truck
is overloading our 10,000-lb. capacity lift
because the 2,500-lb.-rated rear arms are
The Tech Bench
Never rely on hydraulic pressure when resting
a vehicle on a lift. Always lower the vehicle so
the weight is on the safety locks!