August 2022 - 34

TOOL BRIEFING
The ups and downs of
air suspension
We take a look at the components, issues, and fixes.
By Mike Mavrigian, Contributing Editor
the change in ride height (Figure 2); the
control module commands the compressor
to activate, providing additional inflation
pressure to the air springs; and the rear ride
height is restored to original specs.
SYSTEM COMPONENTS
The air suspension compressor supplies the
entire system with compressed air to inflate
the air spring and is generally mounted on the
vehicle's frame or in the trunk. The compressor
assembly consists of an electronic pump;
a dryer filled with a desiccant to absorb moisture;
mounting hardware, including rubber
isolators and brackets; and thermal overload
protection to help prevent the unit from overheating
(burn-out) due to overuse.
Burn-out is normally caused by a small
Hendricks glass tanker air suspension
Courtesy of Hendricks
A
vehicle's suspension system
features springs and
dampers (shocks). The
spring supports vehicle weight
and determines ride height. The
dampers (shocks and struts) provide
control of the springs, dampening
compression and rebound.
Coil or leaf springs provide non-adjustable
support. When overloaded with additional
weight, the springs compress and,
depending on the amount of weight (fore/
aft or lateral), reduce ride height. Air suspensions
utilize inflatable airbags, in addition
to or in place of steel springs. The addition
of rear " air shocks " allowed owners to compensate
for rear weight by simply swapping
out the original shock absorbers with shocks
that incorporate built-in airbags (Figure 1).
Today, many vehicle manufacturers offer
air suspension systems (either as standard
or an option) that replace steel springs with
strut-style air spring/damper units (pneumatic).
These are controlled by an on-board
p Figure 1- Inspect air bag condition. Brittleness, cracks, and/or road debris damage can
result in leaks, which cause the compressor to overwork and overheat.
34 PTEN AUGUST 2022 www.VehicleServicePros.com
air compressor and control modules, regulating
ride height on demand (either by
driver selection or automatically, depending
on design). So when a vehicle owner loads
the rear of a Dodge Ram or Chevy Suburban
(for example), if the vehicle is equipped with
air suspension, the ride height sensors detect
leak in one or more of the air springs, or less
commonly, other components that cause
the compressor to continually cycle in its
effort to maintain the proper vehicle ride
height. Signs of compressor failure include
symptoms such as longer run-time, a louder
noise when activated, or dashboard warning
lights. They alert the driver and repair
shop to trouble and signal that underlying
issues will need to be fixed. Compressor
warranties are often voided when burnout
is indicated. Here are system components:
Air lines: They carry compressed air
to the air springs or air shocks. The lines
are typically high-pressure air lines and
are routed along the frame of the vehicle
protected from heat and pinch points.
http://www.VehicleServicePros.com
August 2022

Table of Contents for the Digital Edition of August 2022
