Late A manifold studs

[Mike(NEOhio)]

7/16 dia., are they fine or coarse threads? I need to put a new gasket in but the nuts and studs are rusted to where I can't see any thread. NLA from Mother Deere.

 

[Mike(NEOhio)]

I'm asking about the top end. Coarse in the block.

 

[matthies]

Doesn't really matter, if the studs and nuts are that bad the rest of the stud will be worse and will need to be replaced. Sorry

 

[Mike(NEOhio)]

I will be replacing them. What I want to know is if they are fine thread at the top or coarse at both ends.

 

[pbb]

I bought my studs and nuts for my A from Sharps and they were corse std threads.

 

[Bob]

If you look at the parts catalog (PC0675) closely, all it says is "nut, 7/16", no part number or thread pitch is shown.

But if you dig into it further, several of the stud part numbers are still available, and when you look them up, they have "UNC" (fine thread) at one end.

Example, A125R, and R2622R.

 

[matthies]

UNC is coarse thread, UNF is fine

 

[Mike(NEOhio)]

I got a gasket and studs from Sharps. Junk, I sent them back along with the fuel line and fittings. The studs were cold rolled steel with cut die cut threads.

 

[Bob]

(quoted from post at 23:56:56 12/01/18) UNC is coarse thread, UNF is fine

Matthies, THANKS for catching/correcting that!

I know better, SOMETIMES!

To be clear, block end is "NC5HF", and interference thread, and other end is "UNC".

 

[Mike(NEOhio)]

UNC then. Thanks, Bob.

 

[machineryman1945]

Mike: The main concern on these bolts is to get the original JD bolt so you want damage the water jacket tubes.

 

[matthies]

We all need correcting at times, we watch each others back. That's why this site is so great, we get along and have fun doing it.

 

[Mike(NEOhio)]

Nice day today so I thought I'd try to get at the manifold studs. Got lucky. Visegrips on the left front one and it snapped off. Left rear broke loose and came off as did the right rear. No luck with the right front so I took a chisel to it and it came loose before it split, took it off with pliers. I may be able to raise the manifold up enough to get visegrips in to unscrew the studs without further disassembly.

 

[Dan in Ohio]

Thanks for the info, we rely on your knowledge and your willingness to share, Thank You both.

 

[Rusty wheel]

The top thread doesn't matter as long as the nut fits the stud. They're pretty expensive, I make my own.

 

[Mike(NEOhio)]

Now that I got them out, they only have 5/8" of full thread at both ends. Dug up the old ones from my H, too, same thing. Going by how they broke and what they feel like with a hack saw and file they're Grade 8.