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Torque Converter and...

Michael Caravaglia

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Joined
Oct 9, 2019
Messages
121
Location
Warwick, New York
Thanks for the update Michael. I wondered if the machinist took care of you.
Sadly he probably didn't want to do a difficult and slow job like this one.
Really good drill bits are hard to find these days.
Have you considered a magnetic base drill ? Having enough room to use it may be a problem. They can be rented in some areas.
Hmmm, not familiar with a magnetic base dril . I'll look into it. Thanks so much
 

Michael Caravaglia

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Oct 9, 2019
Messages
121
Location
Warwick, New York
Or try drilling out with reverse cut drill bits. Get a size slightly smaller than threads. Sometimes the reverse drilling action will grab the threads and reverse them out.
Yes. I noted in my post that I tried drilling a smaller hole into the bolt. I then reverse threaded it and screwed a #8 steel bolt all the way down. However, when I tried to tighten that bolt, rather than loosening the crankshaft bolt, the head of the reverse bolt just snapped off. These bolts are not ever going to be backed out. Drilling seems the only option no .
 

Michael Caravaglia

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Oct 9, 2019
Messages
121
Location
Warwick, New York
In post #28, he said he was using a reverse cobalt.
Micheal ; maybe consider removing the crankshaft and take to a machine shop for an evaluation.
It would be a shame to put a lot of time and money in it only to have the last bolt hole ruined beyond repair.
That would be my typical luck. :(
If all else fails, I'll be forced to pull the motor apart and remove the crankshaft. Then I could bring to a machine shop, or just replace it completely
 

Delmer

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Jan 3, 2013
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If I was you, I'd keep looking for a competent repairman or welder who knows what he's doing. Or find a junk piece of scrap with frozen bolts, tighten the bolts till they snap off, then practice welding washers and nuts on them. And working them a bit at a time till they come out.
 

Bill Edwards

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Dec 28, 2019
Messages
58
Location
UK
I'm sure welding would have got them out, but it seems that he just can't get someone out to it who is any good. Daft but that can sometimes happen.

Drilling them out with a lot of care and picking the threads out is doing the job, slow and tedious but he's having success.
 

Delmer

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if you drill them out, sometimes I'll take a sawzall, or sabre saw, or hacksaw blade, cut the end down so it's just barely more than the teeth left, and cut through the shell of the bolt until you see the threads, just just taking the top off the outer threads. Do this twice about 90 degrees apart, pry out the small section, then collapse the big section and turn it out with a screwdriver.
 

Michael Caravaglia

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Joined
Oct 9, 2019
Messages
121
Location
Warwick, New York
if you drill them out, sometimes I'll take a sawzall, or sabre saw, or hacksaw blade, cut the end down so it's just barely more than the teeth left, and cut through the shell of the bolt until you see the threads, just just taking the top off the outer threads. Do this twice about 90 degrees apart, pry out the small section, then collapse the big section and turn it out with a screwdriver.
I can try this too. Be interested to see how challenging to cut through with only about 1-1/2" of depth to saw back and forth.
 

alrman

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Jun 20, 2009
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QLD Australia
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Diesel Fitter;Small Business Owner;Cleaner
Once the holes are drilled - use a carbide burr to enlarge the holes till you can just see the threads.
Then try to pick out the remaining bolt threads. Once you have exposed the first couple of threads - I use a combination of thread taps intermediate, bottoming & one that has been ground flat - zero taper.

You could use mini burrs with a 1/8" shank to grind the slot instead of trying to use a saw in the hole - but, they break easy.....:rolleyes:
 

Michael Caravaglia

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Joined
Oct 9, 2019
Messages
121
Location
Warwick, New York
Once the holes are drilled - use a carbide burr to enlarge the holes till you can just see the threads.
Then try to pick out the remaining bolt threads. Once you have exposed the first couple of threads - I use a combination of thread taps intermediate, bottoming & one that has been ground flat - zero taper.

You could use mini burrs with a 1/8" shank to grind the slot instead of trying to use a saw in the hole - but, they break easy.....:rolleyes:
All good suggestions. Thanks
 

Tenwheeler

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Joined
Dec 15, 2016
Messages
870
Location
Georgia
Some interesting ideas from different people. Thanks to all of you. Never no when you need to pull a trick like that out of your sleeve.
My first go to is still normally a stainless rod. This one on a Mack was extra challenging. Pulled this off without removing the turbo or anything else extra. Had to hold the stinger at the end and maybe somewhat with the lead. The square is key stock held by another person with vise grips. The socket is to protect the injector hole.
Strike the ark on the stock or vise gripes and work down to the bolt. Then back up. Do not want to weld the bolt to the head.
The heat helps on old rusty bolts and with locktite. Be warned that if it goes bad it can be really bad.KIMG1112.jpeg KIMG1109.jpeg
 

Delmer

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A magnetic base drill is big bucks, you could do just as well with a cheap little drill press, or the style that you clamp a regular drill to, then clamp it to some bars across the bellhousing so you're drilling straight in and centered.
 

Michael Caravaglia

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Joined
Oct 9, 2019
Messages
121
Location
Warwick, New York
Havin' a celebratory beer right now. Just got the 6th and final bolt out. What a project. These bolts were hard as heck! All of the threads seem to be intact.

My method was to drill as close down the center as possible and then keep enlarging the bit size until the walls of the bolt were as thin as I could get them without hitting threads. Then hammering away with a cold chisel until they broke apart.

I purchased a rebuilt torque converter for 300 bucks. I'd hate to put this all back together to find out it's damaged, so I'm changing it out. Worth the extra money.

My biggest concern now is what caused this in the first place. How do the heads of six hardened steel bolts just sheer off and the flywheel break loose? Last thing I want to do is put it all back together to find it just happens again.

Anyone know what could cause this?
 

Delmer

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Post some real close up photos of the broken bolts, and flywheel holes. Show the broken end of the bolts and any worn spot on the bolts or flywheel.

This is a pretty unusual thing to happen. Flex plates crack and break all the time, that's what was suggested earlier. Broken flywheel to crankshaft bolts, I have no experience of, and won't even guess without seeing the bolts.
 

Delmer

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Jan 3, 2013
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HOLES IN FLEX PLATE GOT ENLARGED BY LOTS WEAR, ONCE THE HOLES GOT SLOPPY THE FROWARD AND REVERSE MOTION SHEARED THEM OFF, ALSO THE BOLTS BECOME WORN IN THE FLEX PLATE CONNECTIONS
Pretty sure this is the flywheel to crankshaft bolts that broke.
 

Tinkerer

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May 21, 2009
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9,342
Location
The shore of the illinois river USA
Good call on replacing the torque convertor, Micheal.
What did the hub look like when you found the broken bolts ?
I would be suspicious of the old torque convertor causing the problem with the bolts.
Unless someone before you had the the flywheel off for some reason and didn't torque the the bolts correctly. Like maybe over tightened them and stretched them beyond their limit.
Yes, even a grade 8 bolts has its limits.
 
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