in 1988 GM revised the door hinge system on their medium duty and
full sized pickup trucks.
biggest change was the elimination of traditional “bolted on”
hinges, and the introduction of welded hinges. The hinges were no
longer attached to the door or body with bolts, but were now
robotically MIG welded to the door and body from the back side of
the hinge. The doors were then attached to the body using a
replaceable pin and bushing design.
same system was first used on 1982 S-10 series trucks. The primary
purpose of the changes was to simplify production of these vehicles,
and improve serviceability of the hinge pin and bushings.
hinge system worked very well while these vehicles were relatively
new, but with the passage of time some significant problems began to
The flange of the top
bushing in the upper door hinge would wear away and allow the
bushing to fall out of the hinge.
The hinge pin could
then begin to wear away at the bushing bore in the hinge -
or the pin would wear completely through the bushing wall, and then
against the hinge itself.
The replacement of the
worn out bushings and pins was often made more difficult because the
new bushings would not stay firmly fixed in the hinge since
the bushing bore in the hinge had become oversized from wear.
The locations where
the hinge pin “anchors” in the hinges would also become worn to
the point where they were unserviceable and would no longer firmly
hold the pin in position.
problems eventually lead to a condition where the door(s) will not
close properly even with new hinge pins and bushings installed. This
problem is further aggravated where the vehicle is used in a
of our customers has a fleet of beverage delivery trucks that
experience in excess of 150 open/close door cycles per day. To keep
some of these vehicles in operation the hinges themselves must be
replaced. A ghastly and very time consuming process even for the
experienced professional or fleet garage technician, the old welded
hinges must be cut from the body and door, and then the new hinges
bolted in place. This also involves readjusting the door position
within the cab door opening. Not to mention the fact that the replacement
hinges are attached with bolts, and they cannot match the
structural integrity of the original welded hinges.
the worn out hinges are not replaced they will eventually cause
cracking of the door and in some cases, the cab itself. We have
witnessed several situations where the entire cab was replaced on a
municipal vehicle due to cracking, and wear of the cab at the hinge,
and striker area. On this particular vehicle the sagging door had
actually worn a hole in the cab.
the heart of this problem is the fact that the hinges cannot be
properly lubricated. Aerosol lubricants are commonly used to
lubricate these hinges, but these only lubricate the exterior of the
last hundreds of thousands of miles because they have “pressure
repair system includes a provision for “pressure
lubrication” to ensure the hinges can actually last the
life of the vehicle. In order to do so, we have designed a
system of hinge repair that make no compromises in design or
manufacture. We have utilized every bit of currently available
aerospace, and machining technology to manufacture bushings that can
be installed and “pressure
lubricated” in a very easy to follow method.
have use a custom made step
drill to drill the hinges precisely accept our bushing as
a press fit, and a custom made mechanical
press to do so. We even make a special “Anchor
Repair” (AR) bushing the replace the area of the hinge
where the hinge pins are fixed into the hinge.
entire system is designed to be installed using readily available
hand tools; angle drill, hammer, punch, ˝” wrenches, small grease
gun w/ adapter. We also have available a specially designed door
holding fixture to hold the door securely and safely
during the repair procedure.
Our unique GMC medium duty
truck hinge repair system