Hyland Coupling and unplanned un-coupling

[morribm]

We'd be interested to hear whether anybody else has had their Hyland Coupling become un-coupled while towing? We have!

The situation was that we were coming off a gravel road, which was reasonably steep leading down to the Gwydir river, onto the sealed road which had a prominent central 'hump' to allow run off (I presume) so that the angle between the Cruiser and the ATV2 was obtuse and I was attempting to turn in the direction opposite to that of my exit from the gravel road. Make sense?? I had the weight distribution bars attached.

Half way through the turn, we heard that heart-stopping big noise - 'there's something seriously wrong noise' only to find that the Hyland had un-hitched and the coupling was sitting centimeters above the road but supported by the chains which we always fit over the bars (the chains were crossed over). The coupling would have been buried in the asphalt had we not had the chains over the bars or if we had not had the bars fitted at the time.

As it happens, I ended up right across the road with a ute fast approaching and I had no way of moving quickly and he had no way to go around the obstruction! Who said caravaning is dull??

I think having the WD bars attached was a major contributor to the problem as, when I was trying to turn, because of the relative angle of the Cruiser and the van, the WD bars moved under the A frame and when we moved over the central road hump and I was still in the middle of my attempted turn, the Cruiser and the van were attempting to level out and the bars 'lifted' the coupling off the towball.

This can't happen, I hear you say. Well it can, I assure you! After the event and when we were recovered, we tried a few experiments one of which was to couple the hitch and then by using the wonderful Trail-A-Mate (did I mention that this is a life saver?) we were able time and time again to achieve un-coupling simply by increasing the angle between the tow vehicle and the van - all without touching the T-bar 'hitch clamp' thingy.

I have made a simple pin (bolt with a hole drilled through it) and R clip that will forever more sit in the T-bar tab hole to prevent the T-bar from lifting while it is in place. Subsequent research (Google) has shown that some people have tried a padlock here but they have broken. Well, they would if they get caught between the cup and the side retainers. The force there must be enormous. My gizmo won't get snagged.

Darren Hyland (at Hyland Couplings) was very helpful and on inspection of the coupling decided that the tongue attached to the T-bar was 'rounded off' which was allowing upward pressure combined with a rotatory motion to cause the hitch to un-couple. He replaced the tongue.

Lessons:

Regularly check the 'slop' in your hitch by using a spare towball in the hitch and jiggling it about (Just like you regularly check your wheel nuts)

Have a look at the tongue in the hitch cup to ensure that it is not 'rounded' where it is supposed to sit under the ball

Take you WD bars off before doing any funny angle stuff - not always anticipated when off road, I agree

Seriously consider having a 'gizmo' that will not allow the T-bar to lift unexpectedly

Sorry about the long post, but this was a BIG event!!

Brian & Margie

21' ATV2: LC 100TD

[Webby]

Thanks so much Brian and Margie for taking the time to warn us of this possible danger.

Is there any chance you can provide a picture of your "gizmo" setup? If you have trouble uploading it you can forward it to moderator@kedronownersgroup.com and I would be happy to upload it for you.

Cheers

[RussnSue]

Hello Brian and Margie

Thank you for a very informative post - even though it's also a little scary! I have always had reservations about weight distribution hitches, especially after watching one of the Gall's DVD's where they snapped the tow-hitch clean off a Prado.

We have a Land Rover Discovery 3 and it has self-levelling suspension, thereby negating the need for a WDH. In fact, Land Rover specifically prohibit their use unless you wish to void your vehicle warranty.

Good point about the tongue though. I'll be checking mine after each trip. I know that many people don't use lubricant on their towball - it's a must to prevent wear on the tongue.

Cheers

Russ and Sue.

[CCC]

It would be great to see the 'gizmo'.

Also, for those who have seen the dvds by the Gall brothers, there is one (?) that shows whatelse can seriously occur when the HD bars are left on while travelling on a very rough track.

Your description certainly points out whatelse needs to be done with basic maintenance checks.

Thanks Reg

[morribm]

I'm attaching some images.

The red tie is simply that - keeps the R clip and bolt together when removed.

The T-bar lip shot shows the 'catch' in place. Please note this is a brand new catch and there isn't much of a grip on the protrusion IMO. Can't see why it would not become 'un-catched' if the T-bar happened to lift ever-so-slightly and the internal tongue is not sound.

The other shots are of the tongue itself (wiped free of grease). Please note, this is a brand new tongue - has done no work at all - and note the sharp edge that slips below the ball when hitched. The one that was removed was clearly rounded over thus allowing the ball to slip out given the right conditions.

In the aviation industry and in medicine we are aware that major catastrophes occur when all the holes in the Swiss cheese line up. I believe that this is what happened to us. There was no single issue that accounted for our problem but rather a combination of 'holes in the Swiss cheese'.

Cheers

Brian & Margie