98 Mazda Protégé w/automatic transmission.
Specifically which type/brand should I use on the drive plate to crankshaft bolts during reinstallation?
Here’s what you want to use.
http://www.loctiteproducts.com/p/10/15/t_lkr_blue/overview/Loctite-Threadlocker-Blue-242.htm
Tester
Lock-tite Red. Warning.: Special tools, extra effort or destructive force may be needed for disassembly…
Perfect.
Now what about removing the old sealant from the female threads? A Dremel with a little brass brush attachment or some sort of liquid solvent? A stiff wire brush seems like it might work for the bolts but getting into the threaded holes seems like it could be a nightmare if I don’t know what I’m doing.
What does Mazda recommend, I would try to find the factory spec online. It will most like be listed along with the torque spec. If none is listed and you just want some piece of mind use loc-tite blue 242.
Steve
To clean the female threads use a bottoming tap of the proper thread size.
http://www.toolsavings.com/templates/pricelist.aspx?GroupGuid=140197
A Bottoming tap means the end of the tap is flat instead of having a point.
Tester
Drive plate to crankshaft bolt diameters don’t vary much from car to car do they? What sizes did you usually encounter when removing flywheels/flex plates etc. from little Japanese 4 cylinders? Because I’m thinking I’ll just buy two or three bottomless taps of the most common thread sizes if I can’t find the thread size for my car online.
Take one of the flex plate mounting bolts to the parts/hardware store with you, and walk up to the person and say’ “I need a bottoming tap for this size metric thread.” And show them the bolt.
Tester
LOL. That’s exactly what I’m trying to avoid. Time is going to be a major factor because I’m going to have to have the car back together so I can go to work. That’s why I’m trying so hard to have every single little detail worked out before hand. I only own one car and sometimes borrowing a car isn’t an option.
So if you had to guess, and 10 thousand dollars was at stake, which three taps would you pick?
What’s the metric head size of the bolt?
Tester
Good question. I think. Can you figure thread size if you know the head size? I’ll search online for the head size.
Didn’t you remove the bolts?
What size metric wrench/socket did you use to remove the bolts?
Tester
No. I haven’t even started yet. I’m still in the planning stage.
You’re over-complicating things.
Just rip the tranny out, move it out of the way to get at the seal. Pull the old seal out. Take brake parts cleaner and blast the area clean around where the seal seats.
Install the new seal with a light oiling of the crankshaft.
Install the transmission and apply the Loctite to the threads of the flex plate/torque converter bolts.
Tester
I don’t know what size tap you may need for this but if I made a wild as can be guess I’d say it’s probably a 10 MM x 1.50 thread or possibly a 10 MM x 1.25; leaning towards the former.
I thought of a solution to this last night while lying in bed. I’m about to place an order with jimellismazda so I’ll just go ahead and add a few drive plate bolts while I’m at it. Probably a good idea to have some extras incase something goes wrong anyways.
ok4450, If you’re like me you’re very curious. Even about seemingly trivial things. So I’ll follow up and post the head and thread size of the bolts once my order arrives.
I admit a fault of mine is being curious about the trivial things no matter how insignificant they are.
Disassembling an A/C compressor or even an engine to see exactly why it went belly-up or cutting open failed fuel pumps or ignition modules is a fairly common habit of mine. No Earthly reason other than wanting to take a look just to see… 
Matter of fact, I’ve got a funky ignition switch in a box on the coffee table right now. During a Monday Night Football game I’ll probably wedge it apart and sort out which part went south…
You weren’t too far off ok4450. The tap required is a 12 MM X 1.0. Turns out the 1.0 size is pretty rare. I went to 5 different auto parts stores, Fastenal and a True Value hardware store before deciding to come home and search online. Turns out Amazon has the correct size.
So just to be clear. The tap won’t damage or change the existing threads in any way - but will only clear out the ‘‘old’’ thread locking compound?
Ahh, bottoming tap - my questions are answered… @Tester , that link is bad, what about cutting the chamfers off a tap to get a poor person’s bottoming tap?