Trailer accidently unhitched when reversing

[su888]

Over the weekend i borrowed a dual axle trailer from bunnings, and as I was reversing up my driveway (about a 30 degree slop from the the street) i heard what i thought was the coupling unclip and reversed a bit more and my suspicious were confirmed by the 'lack of weight' on the towball reversing up the driveway.

Luckily all the damage was a slight graze to my rear bumper but nothing serious. However, begs me to ask the question are standard hitches that easy to detach?

I know my boat trailer has a little pin that you can install which i never have used (but will seriously be reconsidering that now) are the pins something that should be installed without question to stop this?

Sorry if this is a stupid question.

[Mace]

A 30 degree uphill push is a big ask, if there was any wear or tear in either the ball or the hitch or other miss alignment than an uncouple would be possible.   Bare in mind that at this angle, the front lip of the hitch may actually make contact with the tongue in front of the towball and actually lever the hitch of the ball.

Another trick for young players is that the older imperial balls (1 and 7/8 inch) are smaller than the now standard 50mm ball. Many modern metric hitches have departed company with an older imperial tow ball.

[Mace]

Also bare in mind that it's the initial change of angle that's the killer, ie, car on flat and trailer heading uphill.

[BigJules]

I not saying you didn't forget to drop the hitch properly, but as one who has made that mistake a couple of times, and twice with serious damage to the rear door of the Cruiser I'd suggest that was most likely.

[Rumpig]

maybe the coupling on the trailer needed adjusting?

[Mace]

I not saying you didn't forget to drop the hitch properly, but as one who has made that mistake a couple of times, and twice with serious damage to the rear door of the Cruiser I'd suggest that was most likely.

Tractor aboard?

[muzza01]

maybe the coupling on the trailer needed adjusting?

That would be my bet. Someone whom borrowed the trailer on another occasion has adjusted the hitch. Not loose enough to come off along flat roads but reversing up your driveway was the clincher.

[Mrs smith]

 

What did they say at bunno's when you told them what had happened ?

[dazzler]

What did they say at bunno's when you told them what had happened ?

"Trailer unhitchings are just the beginning...."

[Ynot]

I have had this on a steep driveway and I think as Mace said it is possible for the hitch to lever itself off the coupling. In my case I had a steep drive with an angled gutter to climb as well.


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[oldmate]

"Trailer unhitchings are just the beginning...."

Yep, we beat it by 10%

[BigJules]

Tractor aboard?

Twice


Julian

[su888]

I have had this on a steep driveway and I think as Mace said it is possible for the hitch to lever itself off the coupling. In my case I had a steep drive with an angled gutter to climb as well.


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I'm pretty certain i had it installed propperly. However, who knows  i've been proven wrong.

I have the exact same situation, angles spoon drain then driveway 30 degrees then level area then tappers off to 15 degrees which makes is awkward when reversing.

How do you overcome this issue? What frightens me is if this happened if i had a big boat with heavy motor on the opposite end.

[Mace]

Is your boat trailer single or duals? With the hires trailer, Do you think any wheel sets (particularly the rears) came off the deck when you reversed up. 

Could you imagine the trailer sitting on the front set only, with the rears clear of the deck, putting extra upward pressure on the hitch?

There are a few particular leverage combinations which could come into effect at any given time.

Yes, there is some adjustment available via the screw nut on top.

From another forum.

Adjusting 50mm Ball Coupling:The coupling should have been supplied correctly adjusted.
If however someone has been playing with it or it needs adjustment for some other reason it's a simple job.
1. Remove the ball from the tow bar.
2. Undo lock nut on coupling adjusting stud.
3. Place ball in coupling.
4. Whilst jiggling the ball slowly and gently tighten the adjusting stud with a large screw driver until you feel all slack disappear from the ball.
5. Back off adjusting stud 1/2 a turn.
6. While holding the stud in position with the screw driver, tighten the lock

No responsibility taken in my behalf, but this seems about right IMO.

[Draggin]

I wouldn't be surprised if it wasn't a combination of factors that caused the unhitching. The coupling probably did need adjusting, your load plus the steep slope contributed to it but most importantly as you stated in your post - YOU DID NOT USE THE SAFETY PIN to prevent the  trailer hitch from unlocking itself.

That simple precaution alone will prevent the uncoupling even if the other factors all come into play. So to answer  the question in your post - YES, use the safety pin at all times 

I speak from experience - one lazy "she'll be right " moment from me and the bow of my boat went through my 'cruiser back window.......................Yeah, yeah, I know - flat ground - just move the boat 5 metres - WHAT WAS THAT NOISE !!!!!!!!!!!!   

[Elky]

the young bloke at my local tyre shop drove all the way to gympie and back with the ball not properly attached, the weight of the tyres kept some weight on it but it eventually fell off 300m from the shop! i always double check my hitchings after hearing that!

30degrees is pushing the limits of a 50mm ball setup tho

[Pirate_Pete]

I have had my boat trailer do the same thing when I forgot to put the safety clip in. The pressure of backing up pushs the handle back up & the slightest side way turn pops the coupling off