Re: [A/S] Re: Hitch receiver Failures

["Carol and Oliver Filippi" <ofilippi@xxxxxxxxxxxxx>]

I do not know what sort of failures are taking place on the factory and
aftermarket hitch receivers.

However, I can offer some suggestions based on my experiences with a
Chevrolet factory option receiver of 1977 vintage.

This receiver was one of the first of the modern design which uses a large
square (some use round) transverse torsion box tube attached to flat side
pieces which run fore and aft and attach to the tow vehicle frame with tabs.

The weakest part of the hitch seems to be the tabs, which are simply bent 90
degrees along the top edge of the side pieces.

The second weakest part is the flat side piece itself, which can flex and
possibly bend.  The side pieces are fine as long as they stay flat and at
right angles to the frame of the tow vehicle and torsion tube.  However,
once the vertical plate gets out of the vertical plane, it can buckle under
the load of the torque applied by the weight equalizing spring
bars.(especially if the receiver gets a little loose from the frame)

Since the laws of physics haven't changed, and the current receivers are
minor variations of this design (slightly thicker side plates), I believe
the following discussion should be of value to my fellow Airstreamers (and
any other trailerer who uses a weight distributing hitch).

My '77 hitch failed in Kings Canyon National Park, partly due to driver
error (I caught the receiver on a big rock.).  Fortunately, I was able to
leave the trailer and drive the tow vehicle to the nearest town (over an
hour away) and located a welding shop that was able to repair the receiver
for me. [ This was an exciting experience, as it was Friday afternoon of a
Labor Day weekend.  The welder was willing to work as long as necessary to
make the repairs. (meanwhile, the shop owner went home!)  He wouldn't even
accept the $20.00 tip I offered him to buy some flowers or other gift for
his wife, since he would be getting home late.  I will be forever grateful
for his dedication.]

Besides straightening the side pieces which had buckled, and replacing a
mounting tab which had sheared off, I had the shop make two strengthening
modifications.

First, I had triangular gussets welded to the tabs and side of the side
plates to stiffen and strengthen the tab.  Second, I had a piece of 2 inch U
shaped channel steel welded to each of the sides of the side plates in a
fore and aft direction.  This latter modification was designed to prevent
the side plate from losing it's vertical plane and bending or buckling under
a fore and aft torsional load.

I never had any problems with the hitch after that.

On my current '89 Chevrolet pickup, the factory receiver was very similar,
except for heavier side plates.  Nevertheless, the first thing I did was to
remove the hitch and have triangular gussets welded to the mounting tabs.  I
did not stiffen the side plates.

So far, I have not had any problems, but have not done a lot of towing with
it, either.

I would be interested to know what sort of receiver failures are occurring.
My guess is that the problems would likely be addressed by my modifications.

Of course the bolts holding the hitch to the frame are very important.  They
should be the heat treated, high strength bolts tightened to the proper
torque.  Besides lock washers, I would also use some Locktite to minimize
the effect of vibration causing the bolts to loosen.

Oliver Filippi