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A great substitute for a "Not Quite 3/4 Inch" hex wrench

Chet Zerlin

Jedi Trainee
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I needed to tighten up the large hex plugs on the side of my transmission. A 3/4 hex wrench is a little too big. When I couldn't find what I needed at local parts houses I visited my local Home Depo and found this. It's a coupling nut that is slightly smaller than a 3/4" hex and fits well into an 18mm socket. More importantly it also fits perfectly into the hex plugs. I just put it in and used my 18mm socket wrench to snug both plugs up.

Total price was $1.22 - by far the cheapest thing I've bought so far for my Healey!



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Whatever works, works, right? You just happened to take the flip-flop method, while I went down the more cluttered steel-toe path ;)




Finished dimension = .7035" (17.87 mm, plus or minus):



Great Pumpkin
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Re: A great substitute for a "Not Quite 3/4 Inch" hex wre

Total price was $1.22 - by far the cheapest thing I've bought so far for my Healey!

Im on my way to Home Depot right NOW !!, You can't buy Loctite 515 for that price--:applause:--:highly_amused:---:encouragement:
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Great idea Randy; Do you use the loctite 515 or now I believe 518 as a thread sealant??

I don't know what the difference in the 515 or 518 is, and I had made a seamless transition from one to the other. I got a deal on ebay some years ago for maybe ten (10) tubes of the 518, and I still have 2 or 3 tubes left. It's good stuff, and I do use it as both, a flange sealant and thread sealant.

Keoke, pretty sure those plugs are only on the side-shift box, leftover from the sedans with a column mounted shift lever (for them the shift linkage passed through those threaded bosses).


Jedi Trainee
What you couldnt find a 23/32 hex drive? What part of the country do you live in that common tools are so scarce?


Great Pumpkin
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Keoke, pretty sure those plugs are only on the side-shift box.

Yeah, I was wondering which side of the box he was talking about.-:highly_amused:


Great Pumpkin
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What you couldnt find a 23/32 hex drive?

Prolly not for $1.22-----:friendly_wink:

Chet Zerlin

Jedi Trainee
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Randy, I first did check your excellent treasure trove of pictures and saw the photos that you posted. Thankfully (since I have no idea what a reading of 7 means on your Starrett gauge) I saw your "milled down from 3/4 inch" notation which provided me with the clue needed! I admit your solution is elegant and something a true mechanic/engineer would much rather do than my flip-flop one but, since we both live in Florida, my guess is that you agree that beach attire - like beach solutions - are always acceptable ;)
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