1G Stripped Hole in block

[Falcon91]

Hey guys, i have a 90' GSX i just got running a few months ago. have going through it trying to make sure everything is up to snuff. i took it down the road and had a bad steering wheel wobble so i pulled the tires and checked everything and it all seems to have been replaced recently. So i continued my search for the cause of the wobble and it led me to the motor mounts which also look to have been replaced recently (prothane front and back) But i noticed i was missing a tranny bolt (not sure how i missed it) and another was loose. so i got a bolt for the missing one and tightened it up but when i went to tighten the loose bolt it seems like its stripped out. The good news is it pretty much solved my wobble problem but I really don't want to pull the motor for one bolt, any idea on way to fix this? Also i noticed my front rotor wheel stud holes are larger than the wheel studs and have a lot of play. is that common? it doesn't seem like the lug nuts would center the rotor on the hub at all.

 

[Mello]

This repair should be a no brainer for anyone working at a machine shop. It sucks that you should really pull the tranny for proper access & room to work but oh well. Mits used a shoulder bolt on these fasteners for a reason & you should not change this. Helicoil the hole 2X diameter in depth than put it back together as if this had not happened in the first place. Helicoils are freakin' tough, mean little boogers. While you have it apart check all the other threaded holes & if any others look compromised, Helicoil them while you're in there. The Helicoil repaired thread will hold more torque than the original threaded hole in the block from factory. Get your chamfering tool, clean up the lead-in chamfer, STI tap drill on location & position (know your GD&T?), tap it, install helicoil, knock out the tang, & move on.

 

[Falcon91]

This repair should be a no brainer for anyone working at a machine shop. It sucks that you should really pull the tranny for proper access & room to work but oh well. Mits used a shoulder bolt on these fasteners for a reason & you should not change this. Helicoil the hole 2X diameter in depth than put it back together as if this had not happened in the first place. Helicoils are freakin' tough, mean little boogers. While you have it apart check all the other threaded holes & if any others look compromised, Helicoil them while you're in there. The Helicoil repaired thread will hold more torque than the original threaded hole in the block from factory. Get your chamfering tool, clean up the lead-in chamfer, STI tap drill on location & position (know your GD&T?), tap it, install helicoil, knock out the tang, & move on.

Yeah I've drilled and tapped plenty of holes in my life just was really hoping there was a way around pulling the trans. and yes I've heard the 304ss helicoils are stronger than than cast. Oh and yes i know my Dims and tolerances and i ordered JIS bolts so so they should be pretty close to OEM.

 

[pauleyman]

I'm sure i'll end up taking the tranny out and re tapping the hole, (i work at a fab shop with a full machine show so i have access to plenty of taps). I'll probably go with one size bigger like a M12x1.5. But the company we buy tooling from suggested loctite thread repair compound. The guy swears by it apparently, any one ever used it?

https://www.mscdirect.com/product/details/00250456?rItem=00250456

Why would you go bigger when a helicoil or timesert would likely work just fine.

 

[AWD-Tony]

I highly doubt you can do any repair without pulling the trans except for trying a tap. I'd just leave that bolt out, make sure all the other bolts are torqued correctly and see if the other bolts come loose after some mileage. If it does, remove the trans an install a heli coil.

 

[jakk220]

I highly doubt you can do any repair without pulling the trans except for trying a tap. I'd just leave that bolt out, make sure all the other bolts are torqued correctly and see if the other bolts come loose after some mileage. If it does, remove the trans an install a heli coil.

No offense but that is a horrible idea. He should fix it properly. All bolts on the bellhousing are important. The transmission can flex and separate from the engine when pressing the clutch if bolts are missing or loose. This causes disengagement issues as you can imagine.

If Mitsubishi only needed to use 4 bolts on the bellhousing to block, im sure that would have done just that.

 

[AWD-Tony]

None taken Jakk. I’m speaking from experience. That same top bolt was loose when I got my car last October. I didn’t have any issues driving home 2 hours. I did get on it a few time and who know how long it has been that way. I’m sure it would 100% cause an issue in a high hp application. Only reason I suggested leaving it was bc op didn’t want to pull the trans. I’m maticulous so I’d fix it if it’s my own.

 

[AWD-Tony]

I’m sure there are thousands of cars on the road with missing lug nut or two. Not the same as a tranny but you get what I’m saying

 

[donniekak]

No offense but that is a horrible idea. He should fix it properly. All bolts on the bellhousing are important. The transmission can flex and separate from the engine when pressing the clutch if bolts are missing or loose. This causes disengagement issues as you can imagine.

If Mitsubishi only needed to use 4 bolts on the bellhousing to block, im sure that would have done just that.

While I don’t recommend not fixing it, the 1g cars only have 4 bolts holding the trans to the engine.

 

[jakk220]

While I don’t recommend not fixing it, the 1g cars only have 4 bolts holding the trans to the engine.

Even worse haha. For some reason I thought the OP had a 2g.

 

[Falcon91]

Ended up getting a couple mm longer bolt with a lock washer and permatex red, two weeks and it’s still tight.