While restoring my 66 BB coupe about 3 yrs. ago we noticed the bolt where the fluid is put into the transmission (4-speed manual)was frozen in place probably by electrogalvanic reaction between two metals (aluminum casing of the transmission and the steel bolt). Several methods such as soaking with liquid wrench and machine oil and sheer stength were tried to loosen the bolt but were unsuccessful. We left it alone for fear of breaking the casing and filled the tranny thru another opening and installed the transmission. I have been driving the car but a day will come when I will need to loosen that frozen bolt. Does anyone have a remedy for this problem? Please let me know how to break it free.
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EDM process
There is an electronic discharge machining process available in major metropolitan areas such as Mobile, Alabama, that can remove corroded ferritic metal plugs from castings without harming the aluminum threads. Each EDM application costs about $50.
All you have to do to prepare for the process is disassemble the transmission main case, clean it of all hydrocarbons, and take it to the EDM shop.
If this sounds like too much trouble, perhaps you can heat the plug with a torch and touch parrafin wax to it. Theoretically the wax will wick into the threads and allow the plug to be turned when it cools. Yeah, that could happen. -
Re: 66 Tranmission Bolt Frozen
I discovered the same thing had happened to my 68. I had previously removed the transmission and drained the lubricant and installed fresh lubricant. I discovered later that I had installed the level check plug to tight. I removed the transmission and ended up rounding off the square plug trying to remove it. I did not seek professional removal help and just drilled out the plug carefully starting with small drill bits and cleaning out the shavings without going through the plug. I did drill through but when I did there was little material to break through to keep out what contamination I could. This was done about 15 years ago and I don't remember much more than this, I did get it out with an minimum contanimation inside the case. Of course I drained the transmission after leaving it in the hot summer sun to warm the transmission to get out any contamination that the lubricant draining would remove. I am still driving the 68 and it has about 95K on it now with a great shifting and performing M-21 4-speed.
I wonder if a square socket and a impact wrench would loosen your plug?Comment
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Re: 66 Tranmission Bolt Frozen
If it were mine, I would take a propane torch and "carefully" heat the aluminum case around the plug. Just about the time it starts to smoke vapors off the surface, turn off the heat and apply the wrench. It should back out easily unleass it is crossthreaded. If the plug threads are pulling aluminum with it as you back it out, keep on comin'. You have nothing to lose at this point as the damage is already done. Clean up the plug threads and seal with teflon tape or dope. It wouldn't hurt to run a pipe tap through the plug hole in the case to clean up those threads. Be sure to grease the tap threads to prevent aluminum chips from getting into the case.
A few things to think about:
Don't get the torch flame against the fiberglass. It is very combustible.
If you have a detailed transmission case, the heat may/will mar the finish somewhat.
Some may say this is dangerous due to a possible explosion of oil vapors inside the transmission. If this bothers you, drain the transmission and take the sidecover loose while you are applying the heat.
Hope it works for you.Comment
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Re: 66 Tranmission Bolt Frozen
These sound like good ideas and thanks for the information in advance.Comment
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Re: 66 Tranmission Bolt Frozen
The parrafin thing works I tried it on exhaust manifold studs after the mechanics at work told me about it .Bill.Comment
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Re: 66 Tranmission Bolt Frozen
Craftsman has 1/2"-drive 8-point sockets from 7/16" to 3/4"; they're terrific for removing the odd-sized square-head plugs instead of rounding them off with wrenches.Comment
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Re: 66 Tranmission Bolt Frozen
I heard of the parrafin trick years ago. I just never had any of the stuff around when I needed it. I talked to my next door neighbor who is a journeyman pipfitter about this. He has used this method and says it does work. If it in fact works, this would be your best bet by far. But, you would heat the plug and not the case with this method.
MikeComment
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