Nut backed off ball caused accident

[iamalienru]

I was heading up to santa cruz ca. in my 40' american eagle I had my motorcycle in tow on a utility trailer. Before I left I had tighten the nut on the ball with an air impact driver the kind that you take lug nuts off a car or truck it was tight lock washer in place. safety chain hooked up all was good. traveling down the 101 near north Hollywood ca. I saw the trailer jumping in my rear camera as I slowed the trailer let loose breaking the safety chain and hitting another car. what a mess. I have never had this happen before but the nut from the ball was laying there on the freeway. now I am having insurance issues on the trailer and coach it was the vacation from hell and it's not over. The only type of ball I will use from now on is one with a cotter pin going through the bottom of the shaft. Uhaul carries them. Sorry for the sad story but i hope this will help others. I still do not understand why that nut backed off

[path1]

iamalienru wrote:
Thanks for all the responses. I have been towing for a long time and never had anything like this happen before. The Saftey chain came with the trailer and I was only hauling an 800lb bike. The bounce when the trailer let loose must have cut the chain thats all i can think of. I made this post for poeple to know no matter how safe it looks or feels things can happen. double up on the safety chains and make the ball has a cotter pin. Many of you know how to tow properly but maybe someone can get some value out of this post

Your a Good person... bringing attention to something so that others might benefit. Hope all goes well for you.

[iamalienru]

Thanks for all the responses. I have been towing for a long time and never had anything like this happen before. The Saftey chain came with the trailer and I was only hauling an 800lb bike. The bounce when the trailer let loose must have cut the chain thats all i can think of. I made this post for poeple to know no matter how safe it looks or feels things can happen. double up on the safety chains and make the ball has a cotter pin. Many of you know how to tow properly but maybe someone can get some value out of this post

[time2roll]

joshuajim wrote:
A couple of drops of RED locktite and you will curse when you try to take it off.

Or just buy a new one if a change is needed.

[Ric_Flair]

joshuajim wrote:
A couple of drops of RED locktite and you will curse when you try to take it off.

Heat it with a propane torch, let it cool, comes right off

[orlandimal]

Ouch! Good thing no one was injured. I have been towing things for 30 years for tens of thousands of miles and never heard of this happening. I have never had a ball nut be even slightly loose and I used to tighten them with channel locks so I am quite sure it was not over 100 lbs torque. I would guess that for those towing bumper pulls it might be something to check at rest/gas stops as I would think it would take a substantial amount of time for a nut to shake its way loose through all those threads.

I also agree that a cotter pin or lock-tite would completely prevent this from happening.

[Ric_Flair]

SDcampowneroperator wrote:
Sorry to read of your trouble. Next time weld the ball on, or the nut to the threads. Been doing it for years. After all, when does anyone change the ball? Even if they did need to, a grinder will cut out the weld.
Nuts will come loose if the hole in the mount is bigger than the ball stem no matter how well torqued. Could that be the cause?

That's a great idea. I've found my nut loose during pre-op checks, and that's with the lock washer in place.

Lock Tight on the threads is another idea, which is what I did, but I'm getting out the MIG before I pull with the bumper again.

[fla-gypsy]

Proper sizing and torque would have prevented the accident and saved you a lot of headaches. Take your experience and use it to become more safety concious. Not all impact wrenches are created equal.

[BenK]

schlep1967 wrote:
To the OP, thanks for posting this. Looks like you made an expensive mistake and by posting this you may keep others from doing the same thing.

Ditto that...many thanks for the OP for posting and getting the spears
and arrows in the back... :S Hope you stick around

In case folks didn't understand why asked what PSI/age/etc of the
impact gun...is that all air impact guns torque is at a specified
PSI and CFM. Oiled or not too. Over time the gun wears. More so if
not taken care of properly (oiled is the biggie) and will lose it
ability to meet torque spec. All my air tools get oiled before hooking
up and during their use

Some depend on torque sticks, which I have and use, but do NOT trust
them. Recheck with a properly set torque wrench and often find not
up to torque (most likely dirt/grim/etc on the mating surfaces)



Lock washer, nylon slug, etc assumes already tightened to spec. This
kind of 'back up' is no different than wired fasteners on airplanes,
race engines, nuclear plant stuff, military stuff, etc and more etc

All are tightened to spec by trained professionals who either know
what they are doing, or under threat of losing their jobs if they don't
Plus super critical will have a 2nd person double check the torque

Of course not rocket science here, but life and limb is on the line



Some of you 'Farmer Tight' folks have the risk of over tightening and
that then will have the stud and/or nut not able to hold...even at
lesser torque...some will actually get it right...but...how would one
be able to tell?


The way of it is that all things have harmonics (vibration) and either
matches the natural harmonic and/or amplitude so high...as to stretch
the stud to even the threads ever so SLIGHTLY.

The nut can and will back off a bit. Over time, the torque (clamping
force) is no longer able to provide enough clamping force to withstand
lesser vibration & amplitude

Back to the OP...again, say much appreciate your posting for 'some'
who might learn from your near disaster experience.

[joshuajim]

A couple of drops of RED locktite and you will curse when you try to take it off.

[Dave_H_M]

WyoTraveler wrote:
Tip the hitch sideways and slide it into the receiver. You don't even need a torque wrench. calculate your weight and length of pipe breaker bar you need and stand on it. 3/4" nut 160 pounds, 1" nut 250 pounds, 1 1/4" nut 450 pounds ft pounds. I personally wouldn't trust any air wrench for torque.

Wow we have some home grown ingenuity how to here. That is what I did when I "torqued" the tractor axle nut on. I was not smart enough on the hitch ball and sat on the ground and had both feet up against the bumper and then proceeded to see if i could turn the breaker bar into a long bow. :S

[schlep1967]

To the OP, thanks for posting this. Looks like you made an expensive mistake and by posting this you may keep others from doing the same thing.

[LarryJM]

VintageRacer wrote:
That's why the instructions that come with the ball say to tighten the nut with a torque wrench, not an impact wrench. Totally your fault. Surprised you admit using an impact wrench on that. You have no idea of what torque you are developing with an impact wrench. Depending on the ball size the correct torque is up to 450 ft lbs.

X2 ... proper torquing would most likely prevented this nightmare now facing the OP. A very expensive lesson learned that was totally preventable.

I also agree that there was some problem with the safety chains and their rating, attachment, etc. because they should not have broken.

Larry

[TugCE]

Not sure if U-Haul still sells them or not but they used to have balls that came with a plastic washer that would squeeze out once the correct amount of Torque was reached. I always thought this was a neat way of making sure the ball was torqued correctly, it also had the cotter pin through the shaft as a safety.

[Supercharged]

nevadanick wrote:
Read his post, he had a lock washer.

Sorry your right, didn't read it right.

[Pauljdav]

I agree with others. Not tight enough. It probably needed 450 foot pounds and you likely got it to 125 at best.