ZBRA

I am working on a LT1 396 stroker car and the A/T flywheel bolts were way overtorqued. A 1/2" snapon impact had a hard time breaking them. In fact, it only broke 3 of them. With a good quality 6-point socket, I rounded the other 3. I am not about to drill into a 4-digit crankshaft. How can I get them out?????

I have tried hammering on smaller sockets, they just twist off. I heated the bolts with a torch and tried to get 'em off. I heated them again and cooled them quickly with compressed air (the real cold stuff in the aerosol can that you clean computers with), that didn't work. They are very round now, as in no corners. Vise-grips won't break them.

What to do??????

All of the bolts were way overtightened on this thing. The torque converter bolts took a 2-foot breaker bar to free. The bellhousing bolts took a 1/2" impact to break. Some dumb SOB has been foolin with this POS. :mad:

Rob 93ZR-1

Would it be possible to grind the heads off. pull the flywheel off then use penetrating oil and vice grips?

Rich B.

Before I tried that, I'd ask my friends for the newest 14 or 16 inch pipe wrench they had (nice sharp edges on the teeth), put an 18 inch piece of pipe on the handle, and try that...

...If you can get to the heads with a pipe wrench...

Otherwise, do the grinding, then use a stud wrench to turn the bolt shanks off...Your tool man or NAPA or whatever will have one (actually, a set of 4)...

Zrxmax

I feel for you guy... It almost makes me want to cuss right now at the stupid sob who did that... if you have good access to the bolts... as in the motor is out of the car... if you can center punch and drill those bolts precisely dead center ( after grinding the heads off and removing the flywheel ) you can drill them out... the holes need to be straight ! When you still have some metal to work with... get a left handed drill bill and varible speed drill and go slowly into the bolt while keeping it lined up as good as humanly possible... as the wall thickness of the bolt gets thinner from the left handed drilling it may come loose... it will seem like a miracle if it works... keep trying the heating and cooling also... it will shrink the bolt... but your messing with the temper in the end of your 4 digit crank... so be careful ( as if I need to tell you that )
take your time and be patient...
Good luck... let us know what happens
Ted
90 ZR-1 # 334
Sun City, CA
Heavy equipment mechanic

Black85L98

Last resort is to grind the heads off but it should work. You will greatly reduce the pressure on the bolts and will have enough left to get some bite with a pipe wrench or stud tool. Good luck. I broke most of my manifold one time and had to drill them out and tap them. BUMMER.

Aggravated4life

Ive used Metrinch tools,sockets etc and theyve never let me down on stripped bolts.
Even really bad ones.
However It can depend on how bad you stripped them.I know power tools help but they always seem to strip the bolts that are stuck on there.Which is why I always use the biggest breaker bar I can use.At least 2 feet long or so.
It also must be hard to use a breaker bar on a flyhweel without forcing the motor to spin over somewhat.
Kinda suprises me because most flywheels dont take that much required torque to install the bolts.
Why people need to use a 400 ft lbs air gun to install this bolts amazes me, been through this myself many times.

Id advise to try and find someone that sells a special socket to getoff stripped bolts and try the breaker bar routine if you can.
Metrinch sockets might work,however I use them for everything else,and they never strip anything.They grab the sides and not the corners.Its nice not to have to buy new bolts anymore.
:)
Good Luck and hope you get it off.

AquaMetallic94LT1

You could use a cut off disk like a dremel and cut the heads into two or four pieces. Then take a chisel and shear the heads off. I think flywheel bolts are grade 8 which are next to impossible to drill into. The remaining parts of the bolts should come out easily once heads off which relieves the pressure on the bolts threads.

jopod

I am by no means an expert on loosening bolts, but my recent experience with my flywheel bolts has led me to believe that the largest diameter dremel bit (I think it's the 1.1" diameter cut-off wheel) and an impact chisel does the best job. Sorry some motherheiffer screwed up your program. FWIW the guy who owned my vette before me torqued down the head bolts to WAY over 150lbs...
broke 2 and stripped 3... :nonod:
bastahd...

RichS

I have welded another larger bolt to the head of the stripped bolt head and then they came right out. Also used those Metwrench things on a few and it worked also.

ZAP

I've got away with using a sharp air chisel . Chiselled then counter-clockwise on tne corner of the bolt. BE CAREFULL . :cheers:

ZBRA

Got 'em off :cheers:

As advised, I grinded the heads off and knocked the flywheel off. I then unscrewed two of them with my fingers and the third with some pliers. Whew....

Thanks dudes. :chevy

cramey

Those were supposed to be 210,000 psi 12 point bolts. A 6 point should not even fit over them if it was the right size.

Definitely go back with GM Flywheel bolts and keep your feet.

ZBRA

I was doing a 4L60E to T56 conversion in a '94 Z28. This is the 3rd I have done in a 4th gen F-body. I have never seen a 12-point bolt on any of them.

I did go back with the correct GM bolts when I installed the manual flywheel, but they are still 6-point. Maybe the 'Vette is different. I don't know, I have never done a 6-speed conversion in a 'Vette, but I have put a ZF6 in an F-body.:)

BBA

Every one I ever saw was 6 point also.

RichS

All stock ones are 6 point as far as I have allways seen.