In my
last column, I talked about troubleshooting the taillight converter on tow
trucks with import chassis. In this column, I'll address another
troubleshooting challenge that comes with import chassis: equipment
mounting.
Like most truck-mounted
equipment, tow truck beds mount to the truck chassis by means of mounting
brackets that bolt onto the outside of the chassis frame. The
mounting brackets fit easily onto most domestic chassis, which, like the
chassis in the upper photograph above, tend to have "clean"
frame rails from the back of the cab rearward. That is, the frame
rails are bare and free of hardware that would get in the way of the
brackets. Import chassis, on the other hand, often come with lots of
hardware on the frame rails behind the back of the cab, as in the lower
photograph. When the bed installer attempts to install the tow truck
bed while working around the hardware on the frame, using brackets shaped
like a jigsaw puzzle piece, using extra-thin bolts and spacers, a
less-than-sturdy piece of equipment sometimes results.
So how should equipment be mounted to a truck chassis?
Here's some dos and don'ts.
Equipment should be mounted:
· With large, good quality nuts and bolts, preferably frame bolts, and
lots of them;
· To the vertical "web" surface of the frame rail, not to the
top and bottom flanges;
· Flat against the frame rail, without any gap or spacers;
· With thick, generously sized brackets;
· In a way that does not compromise the integrity of the chassis frame.
Equipment should not be mounted:
· With too-small nuts and bolts, and too few of them;
· To the flanges of the frame rails;
· With a gap or spacers between the frame rail and the mounting brackets;
· With spindly, contorted brackets that look like a jigsaw puzzle piece;
· In a way that compromises the integrity of the chassis frame. (This
means no welding to the frame unless the mounting's at the very rear end
of the chassis. This also means no drilling into frame flanges.)
When
you check out a new truck or evaluate an old one, it's a lot less
glamorous to roll around looking at greasy frame mounts than it is to
admire the paint job or the wheel simulators. For that reason
equipment mounting issues tend to get glossed over. However, proper
equipment mounting is the very foundation of your entire rig, and it pays
to do some "preventive troubleshooting" by looking at the
chassis and the bed and determining exactly how the two will fit together
for a firm, lasting installation.
