Cracking welds on older Komet trailers

[Bill Daniels]

Last week I noticed a growing hump in the floor over the axle of my Komet
trailer.

Investigating, I found cracked welds where the axle attachment subframe is
welded to the lower longerons of the welded steel truss that makes up the
sides of the trailer. The rear welds on the subframe had failed on both
sides of the trailer allowing the subframe to rotate upward putting the hump
in the flooring. There were also cracks in the longeron itself. Had this
failure continued, it appears that the axle would have been shoved up into
the wings leading edges.

The cause appaers to be the old rubber torsion suspension axle had harded
with age so it no longer absorbed the road bumps. This transfered the loads
to the welded frame which then failed.

The repair will require removing a section of aluminum siding from the steel
frame and a section of flooring over the axle area. The frame will need
re-aligning and reinforcements welded in. The old rubber torsion axle will
also need replacing.

I looked at several other Komet trailers of the same vintage this weekend
and saw various stages of same failure. If you own an older Komet trailer,
carefully check the welds around the axle. If the old rubber torsion axle
has 15+ years on it, it might be a good idea to replace it before the welds
fail. Fortunately, they aren't too expensive - $150 - $200.

Bill Daniels

[[email protected]]

This is a common problem with older Komets, at least those that have
been wheeled across the U.S. for many tens of thousands of miles (mine
was a 1978 that failed after 13 years). Symptoms and repair are as
noted. Early warning is the hump in the floor that causes the wing to
wobble as it's pulled out of the trailer and the spar dolly rides up
over the bump. I was able to gain access from above/below for the
welding by drilling out relatively few pop rivets and bending/propping
up a section of the wooden floor.

This is a different problem than the one of the rubber torsion spring
failing and allowing the trailer to settle on the axle a few inches,
although several of the symptoms are the same (i.e., less axle/longeron
and tire/fender clearance).

I've never heard of it happening on a Cobra trailer, leading me to
wonder if it's really related to hardening of the rubbber or just
failure of welded steel joints. Cobras I've seen are all aluminum; I
don't know if early ones were steel tube.

Now is also a good time to check the welded attachment of the tube that
retains the trailer tongue. The front attach point on mine failed and
the tongue pivoted on the rear attachment, allowing the front of the
trailer to sink down until it came to rest on the brake actuating rod,
applying the brakes. Fortunately neither the brake shoes nor the
bearings were destroyed, although the smoke pouring off the wheels was
pretty impressive. That smoke was the only real trouble indicator since
the trailer continued to track very nicely (although if I'd been real
observant, I might have noticed in the rearview mirror that it was a
few inches lower in front). Note that the tongue itself can be in
excellent shape even when the mounting tube is failing. You have to go
inside the trailer and look under the forward mounting attachment to
inspect it.

Chip Bearden
ASW 24 "JB"

[Bill Daniels]

> wrote in message
ups.com...
> This is a common problem with older Komets, at least those that have
> been wheeled across the U.S. for many tens of thousands of miles (mine
> was a 1978 that failed after 13 years). Symptoms and repair are as
> noted. Early warning is the hump in the floor that causes the wing to
> wobble as it's pulled out of the trailer and the spar dolly rides up
> over the bump. I was able to gain access from above/below for the
> welding by drilling out relatively few pop rivets and bending/propping
> up a section of the wooden floor.
>
> This is a different problem than the one of the rubber torsion spring
> failing and allowing the trailer to settle on the axle a few inches,
> although several of the symptoms are the same (i.e., less axle/longeron
> and tire/fender clearance).
>
> I've never heard of it happening on a Cobra trailer, leading me to
> wonder if it's really related to hardening of the rubbber or just
> failure of welded steel joints. Cobras I've seen are all aluminum; I
> don't know if early ones were steel tube.
>
> Now is also a good time to check the welded attachment of the tube that
> retains the trailer tongue. The front attach point on mine failed and
> the tongue pivoted on the rear attachment, allowing the front of the
> trailer to sink down until it came to rest on the brake actuating rod,
> applying the brakes. Fortunately neither the brake shoes nor the
> bearings were destroyed, although the smoke pouring off the wheels was
> pretty impressive. That smoke was the only real trouble indicator since
> the trailer continued to track very nicely (although if I'd been real
> observant, I might have noticed in the rearview mirror that it was a
> few inches lower in front). Note that the tongue itself can be in
> excellent shape even when the mounting tube is failing. You have to go
> inside the trailer and look under the forward mounting attachment to
> inspect it.
>
> Chip Bearden
> ASW 24 "JB"
>

Thanks for the details, Chip.

As an update, I have the trailer opened up. The lower longerons were nearly
cracked through on both sides which would have left only the upper longerons
holding the trailer together. Total failure was only a few miles away. I
caught it just in time.

BTW, the tounge was replaced with a MUCH stronger "A-Frame" hitch by a
previous owner.

It turned out to be easier than expected to bend the axle mounting sub-frame
back into position with six foot 2x12's and large C-clamps. I straightened
and aligned the trailer with jacks and welded the longerons and sub-frame
with an oxy-acetylene torch. I am thinking that the metal will be
re-normalized by the heat. The next step is to borrow a MIG welder to add
substantial reinforcements.

E-mails from the axle manufacturer (Flexride) indicates that a 10 - 15 year
life is all that can be expected from the rubber torsion axles before the
rubber is "hard as a rock". No surprise there that a 26 year old axle could
break a trailer frame.

So far, I have a couple of evenings into the project and $0.

Bill Daniels