D4 hitch - I think - lugs broke off

With the Mitch Hitch downward forces are shared between the vehicle recovery point where the cross bolt and nylon spacer go and the two rear bolts that bolt the hitch to the safety chain holes cast into the OEM tow hitch socket.

Pulling forces are shared between the above three points but also the OEM tow hitch socket as there is a metal fitting (something like the top end of the plow)that goes in there and is held in place by the rear bolts (rather than the OEM locking mechanism).

So any one point is only taking approx 1/3 of the overall load - even in a breakaway.

Garry

Quote:

---

Originally Posted by gotaflat

I must say I am concerned about the break, particularly as I am loading up about 3t of trailer and horses this morning.

---

1 chain, if long enough to withstand maximum turning to the opposite side, could be attached to the recovery eye as that looks to be a lot stronger than the chain loops.

Just wondering what type of cast is used for the cast section of the tow hitch reciever , Does any one know if the cast is Grey or Ductile cast ?? .

Quote:

---

Originally Posted by Fatso

Just wondering what type of cast is used for the cast section of the tow hitch reciever , Does any one know if the cast is Grey or Ductile cast ?? .

---

Feel free to take a core sample, polish, etch and inspect it through a microscope.;)

I would expect cast steel rather than cast iron. But it's just a guess.

I also expected cast steel however as it appears to have snapped rather than distorted I'm not at all sure. I suspect filing with a fine file would reveal its nature but I'm no metalurgist.

Quote:

---

Originally Posted by garrycol

Paul,

You seem to believe that the chains were not too tight and did not pull the safety shackles out on the bends.

Given that, I guess you believe that the caravan and car parted ways first and then the shackles pulled out of the the holes in the car etc.

Can you tell us what style of hitch you have on your van and specifically why the van and car parted ways. You have alluded to a possible human error and if that is the case can you explain what this error was.(at this stage I think everyone here is interested in learning rather than criticising - let the person who is guilt free cast the first stone and all that)

Also was there a failure of any part of the tow hitch arrangement.

Also I think that your rated shackles might be a bit light (though they held up in this case) given the weight of your van and that in theory the load should be able to be carried by one chain an shackle in a worst case scenario - like a detached, swaying van that has all its weight momentarily in one chain and shackle.

I appreciate you coming on here and explaining the process.

Cheers

Garry

---

Hi Garry,

I know that the chains allowed extreme articulation as I had just left a very tight spot in a full caravan park and had to reverse onto the van at about 75 degrees –chains went on fine, but I made a bit of a mess of the grass as I pulled away.

The hitch on the caravan is the standard Jayco hitch, as are the chains and shackles. Nothing is modified on the van or vehicle.

I don’t know exactly why the caravan departed, but as I said in my last, the one area that I can’t prove as being 100% is the caravan hitch lock as I didn’t put a lock through the eyelet. So whilst I’m 99% sure that it was fully down, the lack of a secondary physical mechanism means that I can’t be 100%.

There was no failure of the tow hitch arrangement, just the safety points.

I note your comment about the shackles, but I don’t want to start another thread as they performed as expected - there are days worth of reading on the topic of shackles on caravan forums.

Hope that helps,
Paul

Quote:

---

Originally Posted by PaulD68

Hi Garry,

I know that the chains allowed extreme articulation as I had just left a very tight spot in a full caravan park and had to reverse onto the van at about 75 degrees –chains went on fine, but I made a bit of a mess of the grass as I pulled away.

The hitch on the caravan is the standard Jayco hitch, as are the chains and shackles. Nothing is modified on the van or vehicle.

I don’t know exactly why the caravan departed, but as I said in my last, the one area that I can’t prove as being 100% is the caravan hitch lock as I didn’t put a lock through the eyelet. So whilst I’m 99% sure that it was fully down, the lack of a secondary physical mechanism means that I can’t be 100%.

There was no failure of the tow hitch arrangement, just the safety points.

I note your comment about the shackles, but I don’t want to start another thread as they performed as expected - there are days worth of reading on the topic of shackles on caravan forums.

Hope that helps,
Paul

---

Paul,

We drove 250 kms with 3.5 tonne of horse float behind....hitch weight 340 kgs.

I thought I dropped the hitch lock down and put the pin in....but must not have. Made it down safely probably due to the very heavy weight. Felt like a dill when I went to remove the car.....felt extremely lucky. That kind of weight detaching would not doubt break my point as your did where the chains are attached. I have very heavy chains and 2.5 tonne for each shackle....more than enough to handle the break.

I will be double checking from now on.

Brett....

Thanks Paul.

I have a OziHitch on my van so unless I forget to put the pin in it should be OK. However I have a standard tow ball socket on my box trailer and I ahve on a couple of occasions put it on and the tongue on the inside was not seated but noticed it before any damage was done - I never lock the side lever (though I check it is in place) but after your experience I might change that.

Now of course the lugs on the side of the OEM hitch should not have failed but I think using the recovery ring as the point the chains are connected to and using the lugs to only activate the breakaway brake mechanism might be the better way to go if OEM gear is being used.

Thanks for your candidness.

Garry

Quote:

---

Originally Posted by garrycol

I never lock the side lever (though I check it is in place) but after your experience I might change that.

---

After the 2nd time my box trailer was left hanging on its chain I now use an R clip which is on my finger if its not on the locked coupling to prevent accidentally not fitting it.

Quote:

---

Originally Posted by Dougal

Feel free to take a core sample, polish, etch and inspect it through a microscope.;)

I would expect cast steel rather than cast iron. But it's just a guess.

---

Was interested as there are different types of cast iron , if in fact the centre part of the tow hitch reciever is cast iron , if it is the generic grey cast then that would not be a good type of cast for a hitch reciever etc or hooking chains too .