Towbar Incident Report

[Ferroequinologist]

I was delivering a deuce to Clintogf (Dawn) and one to TJP (new guy from AZ, I was dropping it off at his father in laws on the north side of ATL) yesterday.

Angie drove my pickup behind me so I would have a way home after I dropped off both trucks.

Anyway, she pulled ahead of me and headed for a rest stop, so I figured she had to pee. So I go to pull off as well, when I feel a jerk and a loud noise, and I look out the driver mirror. The deuce I was towing was still heading straight down the interstate, while I'm taking the ramp!!!!!!

Luckly, I always put my good safety chains on, so she didn't wander too far, and started to follow me onto the ramp. It was kind of hair raising to say the least. I guess the pin broke due to fatigue. I use the snot out of that towbar. Also, after looking at the shakle mounts, the one that broke looked a little bit egg shaped.

No pictures, Angie and I were busy trying to get it hooked back up (glad I bought a spare pin AND had it with me!!!!) It was funny watching Angie do the 'I've got to pee really bad' dance though. lol

so remember, CHECK YOUR PINS AND ALWAYS PUT ON PROPERLY RATED SAFETY CHAINS!!

Service message over.

 

[Recovry4x4]

Was it an actual towbar pin or a shackle pin? Never seen a real towbar pin break before. Congrats on getting it stopped safely. Safety chains, HUGE NECESSITY!

 

[doghead]

Adam, are you sure it broke? or could it have fallen out? Was the pin the correct one for a tow bar that has a 3/16" pin hole that uses a lynch pin? or was it a normal bumper shackle pin that uses a hairpin ?

 

[Ferroequinologist]

No, it was a real deal towbar pin. I know it was properly pinned and secured, I replaced the lynch pin with new ones not that long ago.

 

[RAYZER]

The egg shaped shackle mount probably broke the pin.

 

[doghead]

One last detail on the correct pin, it has the flat side on the head. It has to be installed so that the flat is against the tow bar flat, so it can not rotate in the hole.(causing the lynch pin to be damaged and it could fall out)

 

[Ferroequinologist]

Yes, it was mounted with the flat part against the flat part on the adapter. The shackle hole was ever so slightly egged. When I first mounted it, there was no play in the towbar. I always wiggle everything after the pins are in. I don't know if it broke, and then on it's way out it egged it. The egging was tappered from the center of the hole out one side, it was not even across the mount. like if you put a stick in the ground, then pulled it to one side slightly then pulled it out.

 

[PropDr]

Wow.
That makes me wonder about the mild steel pins I made for mine. Might be time to upgrade to 4340 chromoly.

What size and grade chains did you have on it?

 

[Ferroequinologist]

I have two 40klbs chains that CGarbee was selling for a long time. They have a hook on one end, and are connected together at the other by a master link.

Gimpyrobb has new towbar pins- I PMed him and asked to buy 6, to replace all the ones in my towbar and have another spare new one.

I wish I had a picture of how I hooked them up, I'll draw something crude and post it in a minute.

 

[Ferroequinologist]

Ok, here is the crudely drawn chain set up. You come off the towing truck, and go under and inside the towbar. Then over it ot the outside. Then under the towed trucks bumper, then across the top in front, down the otherside of the frame, back out from under the bumper, over the towbar down the inside, then back out under it to the towing truck.

Let me tell you, this setup works I know! you want some slack but you don't need much.

 

[91W350]

I had a similar freak breakage with a receiver hitch. The pin in the tube broke, allowing my hitch tube and trailer to slide out of the receiver tube. It was dancing back there on the chains and when I got the trailer square with the truck, we stopped. Thankfully the damage was limited to my pickup. I was setting on 65 cruising down the Interstate. I walked back and found half of the pin, it had crystalized and broken. I had just put the fancy locking type on a couple of weeks prior. I used the pointed spoke of an old four way and some rope to cripple into the next town, where I bought a plain old pin. Again, I felt really lucky that nobody got hurt.

 

[dittle]

Your CAD skills are awesome......ok maybe not Just giving you a hard time, the diagram explains it very well.

 

[OLDCHEV4X4]

I prefer to use 2 separate safety chains in case one fails, you still have the other one.

 

[73m819]

It should be a TWO chain setup, if a tb lets go, the chain takes the load, with a SINGLE chain use, the chain will run, allowing ALL the slack to go to the emergency side and in turn allowing more side steer pull, if the TWO chains are done right, there will be almost no slack and and the towed vehicle will steer pretty close to where it is supposed to go.
Just my

 

[Ferroequinologist]

I have very little slack in my set up and the truck didn't move all that far to the driverside. I see what you guys are saying with two chains though. So I will pull the master link and get two 40k hooks and instead of going across over the front of the frame behind the bumper, I will loop each end over the frame and re connect it from now on.

 

[mendo]

I have very little slack in my set up and the truck didn't move all that far to the driverside. I see what you guys are saying with two chains though. So I will pull the master link and get two 40k hooks and instead of going across over the front of the frame behind the bumper, I will loop each end over the frame and re connect it from now on.

I like redundancy, you never know when a componant will break, if you have 2 complete chain setups, one breaks, you got another.

Did you have a little Pucker going on when it broke? I bet you did!!!!

 

[197thhhc]

That sounds like a good idea. I loop around the frame also. but in the past i have'nt looped around the tow bar. I am going to try that from now on. Great info and I am glad you stayed safe.

 

[Ferroequinologist]

Bump for the night crowd

 

[davey8943]

Ferro,

Thanks for sharing... The one detail i want to know is ... How the **** did you get the driver seat separated from your back side?!?!?

I would have been walking around with it attached for WEEKS!!

Glad everything turned out all right!

Dave

 

[3dAngus]

I'm assuming it was a one inch mil-standard pin.
Hard to imagine a pin like that going from a 16000 pound load.

It must have been burred up real bad from to many pulls.

BTW, the egg shaping would have occured when the pin first broke. One side would not be carrying much if any weight. The other side of the pin, while seeing all the slop and holding the weight, would have pulled on the toweye from the bumper in one direction, due to the fact that the entire pin was not in place and leveled from both sides.

There would have been a heckuva lot of follow-on stress in the area immediately following the pin breaking, then pulling itself out moving from perpendicular to the toweye, to parallel after it's ejection.