Jump to content

NATO hitch bolt size?


Mudmonkey
 Share

Recommended Posts

Having looked at the Dixon-Bate site the other day, new ones are supllied with 8.8 grade M12 set screws or bolts. Mine however was bolted on with some strange UNF size.

I believe that it is quite acceptable to use M12 to replace the old UNF bolts.

Glue

Link to comment
Share on other sites

The fitment on any Td5 onwards Defender has to be four M12's, because the threaded inserts inside the chassis crossmember are metric, either 4 x M12s, or for the other sort of towing hitch, 2 x M16s.

Half inch (12.7mm) bolts will fit the hitch but M14s, while they may fit through the hitch, won't fit through the hole in the rear crossmember of an older Defender without making the holes bigger, as they are about 13.5mm.

The tensile strength of four M12 8.8s works out as something like 26 tonnes anyway IIRC so M14s are probably overkill :)

Link to comment
Share on other sites

Yes, they are stamped either 8.8, 10.9 or 12.9 on the head. If unstamped they are unrated - avoid these. Most bolts (i.e. those from screwfix etc) are 8.8.

Some people talk about 10.8's but I have never seen these myself

Link to comment
Share on other sites

yeah, basically, the higher the value, the greater the tensile strength...

i've seen 10.8 bolts, i'm sure there are some on my Disco...

For Landrover applications, regular 8.8 bolts are fine... Landrover use higher spec bolts in a couple of safety critical areas (brake caliper mountings and swivel housing mountings for example) and it would be good engineering practice to replace like for like...

most socket head screws (hex key screws) are 12.7 rated, and are generally cheaper than 12.7 rated bolts...

if you fix a NATO hitch on with 4 M12 x 8.8 bolts, you've got to be doing something seriously wrong to stress them...

Link to comment
Share on other sites

Never seen 12.7 either :huh:

Another way to tell - though not foolproof - is that 8.8 grade or less are usually electroplated, 10.9 grade are usually galvanised, and 12.9 are usually bare steel. there are of course exception so always check the head stamping

8.8, 10.9 and 12.9 are what Land Rover currently uses

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy