Worn Cobra rear-door hinges (both pin and hole)

[Dave Nadler]

Hi Folks - Anybody else had this problem ?
http://www.nadler.com/Antares/Cobra_Antares_rear_door_worn_hinge_closeup.JPG
I've got replacement pins from Spindelberger and
replacement rear corner channels, but I'm thinking
about an insert so all the loads aren't taken in
a thin bit of channel...
Thanks,
Best Regards, Dave "YO electric"

PS: ~55k miles on the trailer.

[T8]

> PS: ~55k miles on the trailer.

You should fly more and drive less :-).


http://www.mcmaster.com/#bronze-sleeve-bearings/=fekwbm

[Dave Nadler]

On Saturday, December 17, 2011 1:59:29 PM UTC-5, T8 wrote:
> > PS: ~55k miles on the trailer.
>
> You should fly more and drive less :-).

8000 XC miles and 150 hours on my Antares this season.
Might even take it out tomorrow; amazingly Dr. Jack
says we'll have a wee bit of lift.

> http://www.mcmaster.com/#bronze-sleeve-bearings/=fekwbm
Yep, Gotta check but I think: 6659K29

Anybody else seen this problem ?
Thanks in advance,
See ya, Dave "YO electric"

[Dave Nadler]

Probably better: http://www.mcmaster.com/#5448T18

[Bob 7U]

I have a 2002 Cobra and the pins had worn through the sidewall of the
trailer before I had a chance to sleeve it. I will be forced to add
some sort of reinforcing plate to the trailer with the bush mounted to
that...
Not the best design for sure and I hope by now they will have fixed
it.

Bob 7U



On Dec 17, 4:24*pm, Dave Nadler > wrote:
> On Saturday, December 17, 2011 1:59:29 PM UTC-5, T8 wrote:
> > > PS: ~55k miles on the trailer.
>
> > You should fly more and drive less :-).
>
> 8000 XC miles and 150 hours on my Antares this season.
> Might even take it out tomorrow; amazingly Dr. Jack
> says we'll have a wee bit of lift.
>
> >http://www.mcmaster.com/#bronze-sleeve-bearings/=fekwbm
>
> Yep, Gotta check but I think: 6659K29
>
> Anybody else seen this problem ?
> Thanks in advance,
> See ya, Dave "YO electric"

[Dave Nadler]

Hi Bob - You flying Sunday ? Dr. Jack says lift !
I may fly the Antares out of Fitchburg as its close
from my house and no one will be flying at Sterling.
Unlikely I'll make it up to Sugarbush with the short day.

Are your hinge pins worn as well as the channel ?

Best Regards, Dave "YO electric"

[JJ Sinclair[_2_]]

On Dec 17, 9:51*am, Dave Nadler > wrote:
> Hi Folks - Anybody else had this problem ?http://www.nadler.com/Antares/Cobra_Antares_rear_door_worn_hinge_clos...
> I've got replacement pins from Spindelberger and
> replacement rear corner channels, but I'm thinking
> about an insert so all the loads aren't taken in
> a thin bit of channel...
> Thanks,
> Best Regards, Dave "YO electric"
>
> PS: ~55k miles on the trailer.

I think the question here is, why is the hinge/flange showing soo much
wear? I havent seen it in my 10 year old Cobra, but I have replaced
the side sliding latch seat with a steel plate after it showed
vertical elongation of the hole (also did the same thing to the bolt
that secures the slide out rails. Maybe this stopped the vertical
movement and took the load off the hinge pins?
JJ

[Dave Nadler]

On Sunday, December 18, 2011 8:57:42 AM UTC-5, JJ Sinclair wrote:
> I think the question here is, why is the hinge/flange showing soo much
> wear? I havent seen it in my 10 year old Cobra, but I have replaced
> the side sliding latch seat with a steel plate after it showed
> vertical elongation of the hole (also did the same thing to the bolt
> that secures the slide out rails. Maybe this stopped the vertical
> movement and took the load off the hinge pins?
> JJ

This trailer has restraints for the wing tip fitted to the
rear door - some funny stuff (loads) going on there. Also
replaced the locking pin (twice now) and yup elongated hole.
Again, this trailer is high-mileage...
Bushing look good to you JJ ?

I'll also replace the locking pin with dual sprung latches
with steel strike/retainer plates (new Cobra standard).

Thanks,
Best Regards, Dave "YO electric"

[Eric Greenwell[_4_]]

On 12/18/2011 6:40 AM, Dave Nadler wrote:
> On Sunday, December 18, 2011 8:57:42 AM UTC-5, JJ Sinclair wrote:
>> I think the question here is, why is the hinge/flange showing soo much
>> wear? I havent seen it in my 10 year old Cobra, but I have replaced
>> the side sliding latch seat with a steel plate after it showed
>> vertical elongation of the hole (also did the same thing to the bolt
>> that secures the slide out rails. Maybe this stopped the vertical
>> movement and took the load off the hinge pins?
>> JJ
>
> This trailer has restraints for the wing tip fitted to the
> rear door - some funny stuff (loads) going on there. Also
> replaced the locking pin (twice now) and yup elongated hole.
> Again, this trailer is high-mileage...
> Bushing look good to you JJ ?
>
> I'll also replace the locking pin with dual sprung latches
> with steel strike/retainer plates (new Cobra standard).

My 1995 Cobra trailer with 170,000 miles still has rear door pins and
holes in nearly new condition. A potential reason for such good service
is my door is pressed firmly down by the top during travel. It wasn't
that way originally, but I added a 0.75" x 0.75" strip of wood to the
top of the door to protect it when it was hanging down and pressed
against the pavement, dirt, rocks, etc during rigging.

I don't know if the door was loose enough to jiggle up and down, but I
suspect so, as afterwards, there was less dust in the back of the
trailer from dirt roads.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

[Steve Koerner]

Dave-

I had this same problem on my Cobra, though not quite as bad as you
have pictured. The Cobra design is ridiculous with an aluminum pin
riding on the edge of an aluminum channel hole. I fixed mine
properly. It was a couple of years ago that I did this so my memory
is a little fuzzy on some details. I replaced the aluminum pin with a
steel pin which I cut from .500” drill rod. I made a new aluminum
block that holds the steel pin on the door and I also made a solid
aluminum block that fits inside the lower channel of the trailer
running fore and aft. I de-riveted the vertical channel on the corner
in order to insert the new solid aluminum block. This block was held
securely in place by the bolts that attach through the skid that lives
directly underneath the channel (I think there were new bolts involved
and some threading of the inserted aluminum block – I don’t recall
that detail). Anyway, one of the aluminum blocks is reamed to .499
for a press-in fit and the other block is reamed to .501 for the
bushing function. This is very solid and has worked great for me.
There is no particular need for a bronze bushing there although it
certainly wouldn’t hurt anything to use one. I did not. The
important thing is that there needs to be a solid block in there and
that the bearing involves a hard metal and soft metal rather than
aluminum on aluminum -- yuk.

Steve Koerner
www.wingrigger.com

[Dave Nadler]

Hi Steve - What do you think of the Cobra (aluminum)
pin into a bushing:
http://www.mcmaster.com/#5448T18
I was planning to do as you did, but it would be
much quicker to just add a bushing and replace
the pins.
Thanks in advance,
Best Regards, Dave "YO electric"

[Steve Koerner]

Dave-

Those bushings are intended to be pressed into solid material. I
ruled out trying to rely on the aluminum channel for the structure as
that was proven by me (and now you) not to work. I think you would
find it difficult to attach the bushing to the relatively thin
aluminum wall and have it stay put. Regarding your aluminum pin...
its obviously trashed like mine was and not usable in a bushing. If
you are going to have to replace the pin, steel would be a much better
choice. I recommend the scheme that I described previously.

Steve Koerner
www.wingrigger.com

[Dave Nadler]

Sorry, I wasn't clear...
I have new non-trashed (aluminum) pins from Spindelberger.
If I press bushings into channel, they can't move and
will stay in place in the channel, rubbing area on pin
is greatly increased, hopefully pin will not abrade as
it will against channel.
Your thoughts ?
Thanks,
Best Regards, Dave

[joesimmers]

Steve, would love to see some pictures of your mod it sounds ideal.

I have always thought that small pin fitting into a thin wall aluminum
channel was very
poor way of getting the job done.

I would also like to see what the "new" cobra setup looks like.

I have a machine shop and could possibly manufacture a few low cost
DIY kits for others.

[Dave Nadler]

Either Joe or Steve - I (and likely others)
would be interested in a kit; ideally new
pin plus insert that can be glued/riveted
inside the existing corner channel with
minimal surgery...
Let us know your thoughts,
Thanks,
Best Regards, Dave

[Steve Koerner]

Joe -- making some kits sounds like a great idea. Please make one for
YO so he doesn't try to stick a bushing in that aluminum channel.

For a long time I had intended to do a write-up on this mod but I
never got to it. I wish I had. I didn't locate any pictures but I
did locate my dimensioned sketch that I made at the time of
fabrication. From the date on the page,I did this in '06. Th sketch
is crude but it should be all you need to make the block that goes
into the channel. The block is 1.00" X .74" X 4.00". It has 3 M8
tapped holes in the bottom and the reamed .501" hole in the side. I
suppose there is the possibility that the skids are located at
different longitudinal locations on various trailers -- so that would
need to be checked first. It looks like I didn't make any sketch of
the part that goes on the door -- I'm thinking it was just an obvious
duplication of the existing part there but with the .500" steel pin in
place of the aluminum metric size pin.

If anyone makes one of these, you should put some grease on the pin or
in the hole when you put it together.

I have posted the sketch here:
http://www.box.com/shared/3ul281v6y0aek31gmva5

Steve Koerner
www.wingrigger.com

[Dave Nadler]

On Saturday, December 17, 2011 12:51:02 PM UTC-5, Dave Nadler wrote:
> Hi Folks - Anybody else had this problem ?
> http://www.nadler.com/Antares/Cobra_Antares_rear_door_worn_hinge_closeup.JPG
> I've got replacement pins from Spindelberger and
> replacement rear corner channels, but I'm thinking
> about an insert so all the loads aren't taken in
> a thin bit of channel...
> Thanks,
> Best Regards, Dave "YO electric"
>
> PS: ~55k miles on the trailer.

OK, lets recap, from thread here and private emails.

As it says above: I have NEW REPLACEMENT aluminum pins
and NEW REPLACEMENT (undrilled) corner channels
from Spindelberger.

I do not want to repeat the problem by using these
as used originally.

The structure (pins/channel) is STRONG enough, but
the aluminum pin on the thin aluminum corner channel
wears excessively. Aluminum-on-aluminum is NOT GOOD.

Suggestions so far via email and in this thread:

A bushing (as suggested by T8 and others) reduces
wear with a better fit and materials that wear less;
anything is better than aluminum-on-aluminum.

A replacement pin of steel (drill stock or cut
bolt with a couple holes through it for mounting;
no complicated machining required) will not wear
out so easily.

A steel insert, block or 1/4" plate bolted to
inside of channel, will give better wear and more
surface.

A tube insert (all the way through the corner channel)
can do likewise. Add a plastic cap on the outside
to keep the dirt out. Easy to make and install
(before riveting in replacement corner channel);
no complicated machining required.

Notes on more modern Cobra trailers:

The bottom of the existing corner channel is not
open; the sidewall extrusion is cut leaving this
area blocked. You cannot just slide a reinforcement
part in from the bottom; you have to remove the
corner channel (bunch of rivets).

The skids are mounted forward of the rear corner
channel.

Further thoughts ?
Thanks in advance,
Best Regards, Dave "YO electric"

http://www.onlinecontest.org/olc-2.0/gliding/flightinfo.html?dsId=2176944

[JJ Sinclair[_2_]]

On Dec 18, 8:07*pm, Steve Koerner > wrote:
> Joe -- making some kits sounds like a great idea. *Please make one for
> YO so he doesn't try to stick a bushing in that aluminum channel.
>
> For a long time I had intended to do a write-up on this mod but I
> never got to it. *I wish I had. *I didn't locate any pictures but I
> did locate my dimensioned sketch that I made at the time of
> fabrication. *From the date on the page,I did this in '06. *Th sketch
> is crude but it should be all you need to make the block that goes
> into the channel. * The block is 1.00" X .74" X 4.00". *It has 3 M8
> tapped holes in the bottom and the reamed .501" hole in the side. *I
> suppose there is the possibility that the skids are located at
> different longitudinal locations on various trailers -- so that would
> need to be checked first. *It looks like I didn't make any sketch of
> the part that goes on the door -- I'm thinking it was just an obvious
> duplication of the existing part there but with the .500" steel pin in
> place of the aluminum metric size pin.
>
> If anyone makes one of these, you should put some grease on the pin or
> in the hole when you put it together.
>
> I have posted the sketch here:http://www.box.com/shared/3ul281v6y0aek31gmva5
>
> Steve Koernerwww.wingrigger.com

Back to the 'why' is the rear door hinge getting all chewed up? I'm
thinking the culprit is the heavy ramp (with jack ('s). The rear door
locks the ramp in place with a bolt that extends into the door when it
is closed. I have found (and fixed) the hole in the door that holds
the ramp, to be severely elongated, why? The ramp & jack are bumping
up and down causing the elongation. This becomes a jack-hammer and the
destructive action doesn't stop with elongating the ramp to door lock.
I believe it is undoubtedly causing the door hinge galling. Recommend
a 1/16 wall, steel plate with bolt hole drilled in center, be pop-
riveted over the elongated hole. Set the new plate so it holds the
ramp & jack firmly against the floor. Then fix the hinge pins ala
Steve & Joe's recommendation.
A good winter project,
JJ

[Steve Koerner]

Dave- Removing the rivets on the corner channel and reinstalling it
with new rivets is not a big deal. That only took a few minutes to
accomplish.

[joesimmers]

JJ, I think you are right on as to the root cause of this, I estimate
my trailer to have less
than 25k miles on it and the hole in the gate that secures the jack is
butchered from slapping around.

Almost always even after a short road trip I open my trailer top and
the gate
just falls to the ground from the securing pin bouncing loose.

[Bill D]

On Dec 19, 6:51*am, Dave Nadler > wrote:
> On Saturday, December 17, 2011 12:51:02 PM UTC-5, Dave Nadler wrote:
> > Hi Folks - Anybody else had this problem ?
> >http://www.nadler.com/Antares/Cobra_Antares_rear_door_worn_hinge_clos...
> > I've got replacement pins from Spindelberger and
> > replacement rear corner channels, but I'm thinking
> > about an insert so all the loads aren't taken in
> > a thin bit of channel...
> > Thanks,
> > Best Regards, Dave "YO electric"
>
> > PS: ~55k miles on the trailer.
>
> OK, lets recap, from thread here and private emails.
>
> As it says above: I have NEW REPLACEMENT aluminum pins
> and NEW REPLACEMENT (undrilled) corner channels
> from Spindelberger.
>
> I do not want to repeat the problem by using these
> as used originally.
>
> The structure (pins/channel) is STRONG enough, but
> the aluminum pin on the thin aluminum corner channel
> wears excessively. Aluminum-on-aluminum is NOT GOOD.
>
> Suggestions so far via email and in this thread:
>
> A bushing (as suggested by T8 and others) reduces
> wear with a better fit and materials that wear less;
> anything is better than aluminum-on-aluminum.
>
> A replacement pin of steel (drill stock or cut
> bolt with a couple holes through it for mounting;
> no complicated machining required) will not wear
> out so easily.
>
> A steel insert, block or 1/4" plate bolted to
> inside of channel, will give better wear and more
> surface.
>
> A tube insert (all the way through the corner channel)
> can do likewise. Add a plastic cap on the outside
> to keep the dirt out. Easy to make and install
> (before riveting in replacement corner channel);
> no complicated machining required.
>
> Notes on more modern Cobra trailers:
>
> The bottom of the existing corner channel is not
> open; the sidewall extrusion is cut leaving this
> area blocked. You cannot just slide a reinforcement
> part in from the bottom; you have to remove the
> corner channel (bunch of rivets).
>
> The skids are mounted forward of the rear corner
> channel.
>
> Further thoughts ?
> Thanks in advance,
> Best Regards, Dave "YO electric"
>
> http://www.onlinecontest.org/olc-2.0/gliding/flightinfo.html?dsId=217....

Dave, you already have lots of good advice but here's another idea.
http://www.popsci.com/diy/gallery/2011-11/tech-support-marshalls-plans?image=4

Metal filled epoxy like this is just as strong as aluminum. It could
be used inside the frame tubes to re-size the holes. If you coated
the new pins with mold release compound and clamped the door in
perfect alignment while the epoxy set up, you'd have a tight, rattle
free fit. The fix would probably last as long as the rest of the
trailer. If it didn't, it's easy to repeat the repair.

[Dave Nadler]

Can't use that, product doesn't even have
the word "Miracle" in the name.
Might work for winch bearings though.

[Craig[_2_]]

On Dec 19, 7:38*am, Steve Koerner > wrote:
> Dave- Removing the rivets on the corner channel and reinstalling it
> with new rivets is not a big deal. *That only took a few minutes to
> accomplish.

Keep in mind that aluminum and bronze aren't very compatible from a
corrosion standpoint. The aluminum is going to be sacrificial to the
bronze. Since you've got lots of aluminum and only a little bronze it
isn't horrible, but a stainless bushing is a better choice if you're
going to stay with the aluminum pins.

Cheers,
Craig

[Larry Goddard]

"JJ Sinclair" > wrote in message
:

> On Dec 18, 8:07*pm, Steve Koerner > wrote:
> > Joe -- making some kits sounds like a great idea. *Please make one for
> > YO so he doesn't try to stick a bushing in that aluminum channel.
> >
> > For a long time I had intended to do a write-up on this mod but I
> > never got to it. *I wish I had. *I didn't locate any pictures but I
> > did locate my dimensioned sketch that I made at the time of
> > fabrication. *From the date on the page,I did this in '06. *Th sketch
> > is crude but it should be all you need to make the block that goes
> > into the channel. * The block is 1.00" X .74" X 4.00". *It has 3 M8
> > tapped holes in the bottom and the reamed .501" hole in the side. *I
> > suppose there is the possibility that the skids are located at
> > different longitudinal locations on various trailers -- so that would
> > need to be checked first. *It looks like I didn't make any sketch of
> > the part that goes on the door -- I'm thinking it was just an obvious
> > duplication of the existing part there but with the .500" steel pin in
> > place of the aluminum metric size pin.
> >
> > If anyone makes one of these, you should put some grease on the pin or
> > in the hole when you put it together.
> >
> > I have posted the sketch here:http://www.box.com/shared/3ul281v6y0aek31gmva5
> >
> > Steve Koernerwww.wingrigger.com
>
> Back to the 'why' is the rear door hinge getting all chewed up? I'm
> thinking the culprit is the heavy ramp (with jack ('s). The rear door
> locks the ramp in place with a bolt that extends into the door when it
> is closed. I have found (and fixed) the hole in the door that holds
> the ramp, to be severely elongated, why? The ramp & jack are bumping
> up and down causing the elongation. This becomes a jack-hammer and the
> destructive action doesn't stop with elongating the ramp to door lock.
> I believe it is undoubtedly causing the door hinge galling. Recommend
> a 1/16 wall, steel plate with bolt hole drilled in center, be pop-
> riveted over the elongated hole. Set the new plate so it holds the
> ramp & jack firmly against the floor. Then fix the hinge pins ala
> Steve & Joe's recommendation.
> A good winter project,
> JJ


Hmmm? What about out-of-round or out-of-balance tires? Maybe a lot of
vibration going on back there...

Just a thought....

Zero One

[Dave Nadler]

Tires balanced, no visible motion in rear view mirrors...
I don't think so...
Best Regards, Dave

[Dave Nadler]

I'm going to use bushings in the corner channels and
a steel (ideally stainless) hinge pin. The pin won't
wear out, and if the bushings wear they're just a
few minutes to replace.

Anybody up for making replacement pin kits ?
Here's a rough (I know, very rough) sketch:
http://www.nadler.com/Antares/CobraRearDoorHinge_4.pdf

Joe ? Steve ?

Alternatively, can anyone recommend a favorite
internet machine shop ?

Happy Holidays,
Best Regards, Dave "YO electric"

PS: Wear on pins is only on one side: door moving
downwards when closed, or upwards when open. I think
most likely I've caused this by cranking trailer nose
up against door opened on ground to steady rear of
trailer(instead of using the cranky rear jack stands)...