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Tr4aJim

Dog bolt size

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Folks, what is the size of the “dog bolt” holding the fan extension on a Tr4a? I tried a 1 &1/8 socket but it’s a bit loose and I don’t want to round it over. I’m assuming it’s Imperial and not metric.

thanks

Jim

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A 5/8th UNF threaded bolt (common for many dog bolts) has a 1" 1/16th AF dimension from memory. Of course you could measure it ?

Mick Richards

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There is a problem with this bolt in that it is only just hexagonal. It has rounded corners.  Why - I haven't a clue.

 

Roger

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Mick, I just borrowed a 1&1/16 socket and it doesn’t fit:blink: . So it must be something between 1/8 and 1/16. Maybe it is metric. I tried measuring and it looked like 28mm (of course with my eyes it might be a foot and a halfB)).

Roger,  It did look a bit rounded to me. I thought it was from previous mistreatment.

I guess last resort is an adjustable wrench and a length of pipe.

thanks

Jim

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10 minutes ago, Tr4aJim said:

Mick, I just borrowed a 1&1/16 socket and it doesn’t fit:blink: . So it must be something between 1/8 and 1/16. Maybe it is metric. I tried measuring and it looked like 28mm (of course with my eyes it might be a foot and a halfB)).

Roger,  It did look a bit rounded to me. I thought it was from previous mistreatment.

I guess last resort is an adjustable wrench and a length of pipe.

thanks

Jim

Just thought, as Roger says the heads on the original bolts are rounded, if you are using a Bi Hex (multiple hexagon shape) socket they locate on the corners...there ain't any and it will feel loose until the corners locate on the flat. Of course maybe you've used a single hexagon shape socket but if not give a "1 1/8th" a shot and see if it will locate on the flats.

I assume you were joking about an adjustable...err.

Mick Richards

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Mick, yeah I used bi-hex sockets. I’ll see if I can find single hex ones. Oh yeah, of course I was joking (as I casually toss a shop rag over the pipe wrench-_-).

John, that would be great, thanks!

Jim

Edited by Tr4aJim

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Folks, I found a 1&1/8 single hex socket, and it worked great! Dog bolt came out without much struggle.

Thanks for the help!!

Jim

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On my car a 1/2"Whitworth/9/16" BS socket is a snug fit on this bolt head, which is 0.920" across flats.

Tim 

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I printed a sheet of all sizes, metric / UNF / WW in ascending order and fitted it to a post of the car lift. Very helpful if a size needed which is just a bit more or less. Often a metric / UNF / WW spanner will fit. I use it all the time because I can never remember if for example 7/16" is just a bit bigger or smaller than a 11 mm spanner!

nut-bolt sizes.jpg

Edited by badhuis

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Folks,

This bolt came out relatively easy for me, but I have read where others have had a tough time getting this bolt loose. When refitting the bolt, is there any issue to using anti-seize compound on the threads to future-proof it?

Also there is a thin smooth washer on this bolt. Should that washer be replaced or can it be reused?

BTW - looks like my car has a bolt from a Tr4, as it has the lugs for a hand crank.

thanks

Jim

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3 hours ago, Tr4aJim said:

Folks,

This bolt came out relatively easy for me, but I have read where others have had a tough time getting this bolt loose. When refitting the bolt, is there any issue to using anti-seize compound on the threads to future-proof it?

Also there is a thin smooth washer on this bolt. Should that washer be replaced or can it be reused?

BTW - looks like my car has a bolt from a Tr4, as it has the lugs for a hand crank.

thanks

Jim

Jim,

All Triumph threads are fitted dry, the crank main bearings, conrods, camshaft anything you can think of... dry.

if you put anti seize on the bolt thread and tighten it, whatever torque you use... will not be the torque that is applied.

Because the anti seize will reduce the tightening friction and the sticking of the bolt ( we call it “stiction”). Which means the torque will be OVER applied ie greater.

As I said before, I use 120 lb ft ( the bolt should be good for 150) fitted dry with that small washer in place. Up to you what you wish to do.

Mick Richards

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Hi Jim,

           the bolt with the lugs was probably ST using all their old stock.

 

Roger

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Thanks Mick, glad I asked first!

Roger, makes sense as mine is a ‘65.

Jim

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