Differential drain plug size
Discussion
Hi all,
Just changing my diff oil and the drain plug appears to be very tight and an unusual size. Any idea what size so I dont end up rounding it off. Its smaller than 13mm but bigger than 12mm and a standard 1/2" socket still feels too big. Any ideas so I can get the exact size socket to avoid damageing what appears to be avery tight nut!?
Just changing my diff oil and the drain plug appears to be very tight and an unusual size. Any idea what size so I dont end up rounding it off. Its smaller than 13mm but bigger than 12mm and a standard 1/2" socket still feels too big. Any ideas so I can get the exact size socket to avoid damageing what appears to be avery tight nut!?
Fast by Fred said:
Wow, no wonder im having trouble. The fill nut came off very easy for me the drain plug however is a different matter. I don’t have access to a welder so will have to get creative. Mine is smaller than 13mm but larger than 12mm so very odd size!Mine is M12 (std 1.75 pitch) x 25mm. As previously stated, with a 17mm flanged hex head.
Which is odd as the 8 rear cover bolts are 5/16" UNC! ...no guarantee that all are the same, possibility it's been rethreaded/helicoiled.
Edit: ...been thinking, this drain plug thread should surely have been 7/16" UNC originally, anyone else care to check theirs? All the other threads on the diff are imperial...
The pitches are too close to call ; 7/16" UNC is 14tpi which equates to 1.81 mm, M12 (coarse) is 1.75 mm.
Dia. of M12 bolt is 11.8 mm whereas dia. of 7/16" bolt is 11.1 mm.
My plug's thread measures 11.7 mm. and a new M12 bolt is a lovely fit, so I am 100% sure mine is M12.
I don't have a 7/16" UNC bolt to try, but I would expect it to be very loose.
Which is odd as the 8 rear cover bolts are 5/16" UNC! ...no guarantee that all are the same, possibility it's been rethreaded/helicoiled.
Edit: ...been thinking, this drain plug thread should surely have been 7/16" UNC originally, anyone else care to check theirs? All the other threads on the diff are imperial...
The pitches are too close to call ; 7/16" UNC is 14tpi which equates to 1.81 mm, M12 (coarse) is 1.75 mm.
Dia. of M12 bolt is 11.8 mm whereas dia. of 7/16" bolt is 11.1 mm.
My plug's thread measures 11.7 mm. and a new M12 bolt is a lovely fit, so I am 100% sure mine is M12.
I don't have a 7/16" UNC bolt to try, but I would expect it to be very loose.
Edited by TwinKam on Wednesday 3rd March 16:39
TwinKam said:
Mine is M12 (std 1.75 pitch) x 25mm. As previously stated, with a 17mm flanged hex head.
Which is odd as the 8 rear cover bolts are 5/16" UNC! ...no guarantee that all are the same, possibility it's been rethreaded/helicoiled.
Edit: ...been thinking, this drain plug thread should surely have been 7/16" UNC originally, anyone else care to check theirs? All the other threads on the diff are imperial...
The pitches are too close to call ; 7/16" UNC is 14tpi which equates to 1.81 mm, M12 (coarse) is 1.75 mm.
Dia. of M12 bolt is 11.8 mm whereas dia. of 7/16" bolt is 11.1 mm.
My plug's thread measures 11.7 mm. and a new M12 bolt is a lovely fit, so I am 100% sure mine is M12.
I don't have a 7/16" UNC bolt to try, but I would expect it to be very loose.
Holy Dingbats Rik, You should write a book on your thread knowledge and experiences Which is odd as the 8 rear cover bolts are 5/16" UNC! ...no guarantee that all are the same, possibility it's been rethreaded/helicoiled.
Edit: ...been thinking, this drain plug thread should surely have been 7/16" UNC originally, anyone else care to check theirs? All the other threads on the diff are imperial...
The pitches are too close to call ; 7/16" UNC is 14tpi which equates to 1.81 mm, M12 (coarse) is 1.75 mm.
Dia. of M12 bolt is 11.8 mm whereas dia. of 7/16" bolt is 11.1 mm.
My plug's thread measures 11.7 mm. and a new M12 bolt is a lovely fit, so I am 100% sure mine is M12.
I don't have a 7/16" UNC bolt to try, but I would expect it to be very loose.
Edited by TwinKam on Wednesday 3rd March 16:39
3/4" AF is 19.05mm. It's one of the few sizes that an imperial or metric socket will fit. 
Another one is 1 1/16" = 26.99mm.
I've doing a bit of this conversion recently to get a socket to fit the pinion nut on my Triumph Toledo. I have had to order a 1 1/8" AF socket. I have slightly too small and slightly too big in my toolbox, of course I have .......
Another one is 1 1/16" = 26.99mm.
I've doing a bit of this conversion recently to get a socket to fit the pinion nut on my Triumph Toledo. I have had to order a 1 1/8" AF socket. I have slightly too small and slightly too big in my toolbox, of course I have .......
sixor8 said:
3/4" AF is 19.05mm. It's one of the few sizes that an imperial or metric socket will fit.
Another one is 1 1/16" = 26.99mm.
I've doing a bit of this conversion recently to get a socket to fit the pinion nut on my Triumph Toledo. I have had to order a 1 1/8" AF socket. I have slightly too small and slightly too big in my toolbox, of course I have .......
Good info Another one is 1 1/16" = 26.99mm.
I've doing a bit of this conversion recently to get a socket to fit the pinion nut on my Triumph Toledo. I have had to order a 1 1/8" AF socket. I have slightly too small and slightly too big in my toolbox, of course I have .......
The 19mm nut is just for info (Proof it is a metric thread)
TwinKam said:
No need Paul, it's all there in the Holy Bible already 
PS What's with the new moniker?
Thanks to your earlier advice, I have equiped myself with one.PS What's with the new moniker?
Just need to acquire an electron microscope to read the damn thing
Name changed due to the relentless grief I was getting about
"What an arrogant asshole you are for thinking you are Mr. Cerbera"
'Fast by Fred' was a company that I wanted to start with My Old Man
Fast by Fred said:
TwinKam said:
No need Paul, it's all there in the Holy Bible already
PS What's with the new moniker?
Thanks to your earlier advice, I have equiped myself with one.PS What's with the new moniker?
Just need to acquire an electron microscope to read the damn thing
Name changed due to the relentless grief I was getting about
"What an arrogant asshole you are for thinking you are Mr. Cerbera"
'Fast by Fred' was a company that I wanted to start with My Old Man
TwinKam said:
What's with the new moniker?
Fast by Fred said:
Name changed due to the relentless grief I was getting about
"What an arrogant asshole you are for thinking you are Mr. Cerbera"
'Fast by Fred' was a company that I wanted to start with My Old Man
What arrogant asshole told you that? T"What an arrogant asshole you are for thinking you are Mr. Cerbera"
'Fast by Fred' was a company that I wanted to start with My Old Man
t!You'll always be Mr. Cerbera to me, Paul
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