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Stacey007

Member Since: 25 Sep 2015
Location: Cheshire
Posts: 3750

Bolt size for towbar drop plate and Nato hitch

Hello

Following from my Nato hitch / Sankey Trailer my drop plate arrived on Friday but no Bolts.

This is what I have currently.

Click image to enlarge

and this arrived to fit the nato hitch on.

So it should be able to fit like this one?

Click image to enlarge

What size bolts are No,1 and No,2 if you can tell on my picture? the bolt I think says M8,8 but they both do and they are different sizes?

Also (I'm not doing it this way just curious) the cross member is threaded and the bolts do tighten up straight into this from the nato hook. I cannot however see how you get to the back of this to attached a nut? or a plate for strength? are these not designed like that. It feels like a box section the nato hitch would just use the 4 bolts straight into cross member.

Thanks

17th Jan 2016 7:54pm

JAY BOY

Member Since: 04 May 2010
Location: Not here
Posts: 1706

I'm not 100% sure but i think there 14mm

17th Jan 2016 7:55pm

Stacey007

Member Since: 25 Sep 2015
Location: Cheshire
Posts: 3750

Thanks but there are two different sizes?

17th Jan 2016 7:57pm

JAY BOY

Member Since: 04 May 2010
Location: Not here
Posts: 1706

Just checked

16mm for the big bolt
12mm for the smaller

17th Jan 2016 8:07pm

Stacey007

Member Since: 25 Sep 2015
Location: Cheshire
Posts: 3750

^ Ace

I just googled way and found the standard towbar bolt is a :-

M16 x 50mm Tow Bar Trailer Ball Hitch Bolts Nyloc Nuts Washers Grade 8.8

so the 8.8 on the bolt is the grade... That fooled me,

Will look others so I;m guessing its a M12

Thanks

17th Jan 2016 8:13pm

JAY BOY

Member Since: 04 May 2010
Location: Not here
Posts: 1706

I just measured them with a vernier so thats correct sizes.

17th Jan 2016 8:15pm

Retroanaconda

Member Since: 04 Jan 2012
Location: Scotland
Posts: 2645

The info on the bolt head is the grade. In this case 8.8 - make sure anything you replace them with is the same grade. The M likely stands for metric.

On later (Td5 onwards) crossmembers the four M12 holes that a NATO hitch would bolt into have captive threaded inserts in. This is presumably due to the fuel tank blocking access to the rear in order to fit nuts, however it does prevent a spreader plate on the rear as you have guessed. And I'm not sure how strong the threaded fittings are either, strong enough I am sure however I do prefer the known strength of a bolt and nut.

When I had a NATO hitch on my 90 briefly I did this:

http://www.retroanaconda.com/landrover/200...-recovery/

17th Jan 2016 8:16pm

Stacey007

Member Since: 25 Sep 2015
Location: Cheshire
Posts: 3750

^ Thanks both

Like you I would rather have a plate or at least a nut on the end of the bolt if using the 4 bolts on the cross plates...

Given I cannot add a spreader plate the drop hitch I think is a better option for me.

Many thanks

17th Jan 2016 9:00pm

blackwolf

Member Since: 03 Nov 2009
Location: South West England
Posts: 17382

2007 Defender 110 Puma 2.4 DCPU Stornoway Grey

The holes in the cross-member are specifically designed for the fitment of a towing attachment (be it NATO pintle or a four-bolt jaw) and I really don't understand why anyone should be remotely reluctant to use them for the job they were designed to do.

Very early vehicles (S1) had the crossmembers tubed and were of ample strength with a bolt straight through. When the tubes were 'value engineered' into oblivion, a spreader plate had to be used to prevent the bolts pulling through the crossmember. When the fuel tank made this jmpossible and captive threaded inserts became the norm, the crossmember was reinforced appropriately. There is no reason not to use these fittings for their intended purpose.

If you fit a NATO pintle directly to the crossmember to tow a Sankey with a rotating lunette you should fit a reinforcing plate between the hitch and the crossmember. This seems counter-intuitive, but the reason is that if the trailer approaches the 'jacknife' angle to the towing vehicle the lunette will swivel downwards and lock - it will not return to the horizontal when the vehicle pulls forward and the angle straightens (this is precisely the reason why the rotating lunette was phased out).

If this happens, something inevitably is going to bend. Without the reinforcing plate, it will be your crossmember, which will be destroyed quicker that yoh can read this post. With the plate and some luck, the shaft of the lunette will bend though 90 degress and the crossmember will escape damage. Sadly it is more likely both will be wrecked.

17th Jan 2016 11:09pm

Stacey007

Member Since: 25 Sep 2015
Location: Cheshire
Posts: 3750

Thanks for your reply.

I would like to retain my current towball and the fact the NATO hitch will not fit easily into the cross member with the std towbar means the drop plate will make life easier?

The NATO hitch is also quite big and bulky so when not in use can be left in the boot.

We use the boot to sit the kids in / get them changed / weelies off etc so it could be in the way if permanant .

Good to know it would be OK though.

Thanks

17th Jan 2016 11:28pm

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