Technical Year 2000 Fiat ducato Speedo cable retaining bolt.

[Rodney 2000]

Hi folks… I need some help. I’ve lost the retaining bolt that holds the Speedo into the gearbox.., it should fit on the rhs next to the cable pin. I’ve tried standard

M6 but these are too small and M8 is too big. Any ideas what I need and where to get something suitable from? Thanks

 

[Communicator]

I do not know the answer to your query, but working from first principles here are a few thoughts or suggestions.

M7 though rarely used, is a recognised standard and has the same 1mm pitch as M6.

It is good engineering practice to use coarser threads when tapping into aluminium castings.

This leads to considering 1/ 4" UNC (Unified National Coarse) as unfortunately the superior designed BSW (Brtish Standard Whitworth) is obselete. 1/4" UNC has 20 threads per inch. For automotive use you should normally consider 8.8 Ton tensile strength bolts, but in you application anything is better than nothing. A2 stainless steel is worth considering.

Both M7 and 1/4" UNC are available in various lengths on Ebay.

Please post your eventual match to help otheres in the same situation.

 

[jackwhoo]

If you are stuck use a cable tie as it is a through hole

 

[Communicator]

If you are stuck use a cable tie as it is a through hole

I was not sure, but in that case estimating the required length of bolt should be easy.

 

[Rodney 2000]

I was not sure, but in that case estimating the required length of bolt should be easy.

Yes.. I think I can establish length easily… it was the size and thread pitch I was worried about.. I’m keen not to damage the treat inside… thanks for the ideas

 

[Rodney 2000]

I do not know the answer to your query, but working from first principles here are a few thoughts or suggestions.

M7 though rarely used, is a recognised standard and has the same 1mm pitch as M6.

It is good engineering practice to use coarser threads when tapping into aluminium castings.

This leads to considering 1/ 4" UNC (Unified National Coarse) as unfortunately the superior designed BSW (Brtish Standard Whitworth) is obselete. 1/4" UNC has 20 threads per inch. For automotive use you should normally consider 8.8 Ton tensile strength bolts, but in you application anything is better than nothing. A2 stainless steel is worth considering.

Both M7 and 1/4" UNC are available in various lengths on Ebay.

Please post your eventual match to help otheres in the same situation.

M7 was the required bolt….thanks for your guidance

 

[robin123]

Who uses M7 threads? Is this some sort of fiat madness!

 

[Communicator]

Who uses M7 threads? Is this some sort of fiat madness!

I think that there were some on a Renault 14, that I owned many years ago. Less extraordinary, but worth noting is that the capitive nuts under the body are typically M8 Fine.