Help! Snapped flywheel-crank bolt! Retap?

[AJK]

Broke a flywheel to crankshaft bolt, tried drilling and Easy-Outing it out, no good. Threads are likely damaged. What is the best course of action? Can I drill and retap the hole to M12x1.25 instead of the M10x1.25, as long as I keep the bolt grade 8 (and do the same on the opposite side to keep it balanced)?

Or maybe can I do a stud and bolt combo? Can a stud be two different sized threads? One section (in the crank) m12 and the next section (through flywheel) m10? That way the flywheel would not need to be modified.

Or is my best bet to pull it all apart and replace the crank?

Correct me on anything if I am wrong, and please point me in the right direction!

Thanks, and good luck on your projects.

A.J.

 

[nick88]

Heli coil.

What where you doing to be able to snap one off? I have seen some people impact them on, on a b16 and not snap any of them off.

 

[AJK]

What tools are needed for this? Do I need the full Helicoil kit? Or just the inserts and tap?

I broke the bolt by trying to install mk4 dual mass flywheel bolts onto a 1jz flywheel. I didn't pay enough attention, and now I'm paying for it. The extra inch of length caused to bolt to break due to the added leverage and angle, the head of the bolt wasn't even close to the flywheel.

 

[AJK]

The HeliCoil seems to be my best bet. Any more info on these? What size Helicoil do I need to correct this and reuse the stock m10x1.25 bolt? Will I need to drill the opposite bolt hole on the crank, and insert another Helicoil to balance it?

 

[Evilempire1.3JZ-GTE]

If you have enough of bolt vice grips weld a sturdy rod to it and remove it.
If your really good you can drill it out with reverse drill bits and if it doesnt catch & come out when your close to the threads weld ito then take it out then.


You can heat it up with a torch causing the piece to swell and break loose easier too.

 

[hvyman]

Metal expands with heat.

Time serts are better than heli coils.

Impacting bolts on is just stupidity and honda owners are lame. Torque wrnches were made for a reason.

Pb blaster and drill a smaller hole in the middle of the bolt. Use a reverse drill type bit to remove the broken part.

 

[AJK]

Tried many different ideas to remove the bolt. I had drilled through the middle and wound up using a chisel to crack the remaining bolt into pieces which fell right out. And the best part is, I was wrong about the threads, the crank is fine. Just be patient and keep trying, that's what I learned.

 

[Ryan_V]

Hmm..sure nothing fell through the crank into the pan? Maybe pour some oil through the crank bolt hole and drain the oil to be safe??

 

[Altezza576]

Remove the Crank, take it to a machine shop. They fixed my crank in 30mins when I messed up the threads for crank bolt with a puller tool.

 

[hvyman]

Well a extra inch of length in a bolt is a lot of threads to be adding.

 

[AJK]

The pan, and rear main bearing casing were off, it's all clean.

 

[hvyman]

Off??? Do explain?