super C Crank pulley- What now

I have had some great info from you guys about removing and replacing the crank pulley but I am afraid I may have messed up. I was replacing the pulley, when the all thread broke off inside the crank. I tried to drill it out starting with a small drill bit, and it broke off. Now I can't drill it out, because of the broke bit. And I can't get the drill bit out. Do I just keep trying to drill it out until I get past the broken bit, if possible. Is there another way to put on the pulley, Thanks

Use a pin punch (or oil quenched pole barn nail) to break up the drill bit. It will take some effort, but should splinter with some angular hits.
Another possibility is to use a small cold chisel to spin the rod out by chiseling CCW on the perimeter of the broken end. If the rod snapped from tightening a nut on the pushing plate, or collar, it might not be tight in the threads at all.
Welding a nut on the end of the rod (through the hole in the nut to the shaft of the ready rod) will also work. Use a bolt one size smaller than the ready rod (9/16" nut on a 5/8 ready rod) let it cool to shrink, and turn out with socket.
When it is off, polish out the inside of the pulley until it goes on by firm hand pressure at least 1/3 of the way. JimN

You've got a bit of a mess but don't lose your head. It happens. And there is a way out.

A few questions. How much of the drill bit is in there? Is it broken off flush with the face of the broken off allthread or sticking out? Same thing with the allthread. How much if any of it is sticking out the front of the crank? How far on is the pulley? Can you get it back off?

I'm the sort of guy who's cleaned up enough cobbled-up messes that my conscience won't let me leave a mess for the next guy. If the pulley is all the way on, you could leave it as is and run it, but that allthread is only gonna become harder to get out over time.

Getting it out will likely mean pulling the pulley back off for starters. If it isn't all the way on, a little fast heat from a Mapp torch should loosen it up enough to get it off.

From there a lot depends on the answers to the kinds of questions I posed. It could be as easy as a larger carbide (i.e., HARD) bit to drill out the stub of the drill bit that's in there, and then using a left-twist drill to get the allthread out. Worst case would be having to weld a nut over the allthread, snapped-off bit and all, to get the whole mess out at once. Welding on a crank is always touchy and at the lest will mean a new seal for the timing cover, perhaps more. But there's a lot of options/possibilities in between.

Bottom line . . . it's all fixable, but more details will generate more good ideas to get you out of your fix.

Let us know.

This is the very reason I designed and built the puller to put the pulley back on. That and it is a lot simpler to use hydraulics than mechanical, such as the method you were using.You need 2 pieces of 5/8 althread, a hydraulic jack that will work laying on its side. Use the 14 inch 1 1/2 square tubing in my design to push you pulley on to the crankshaft as shown in the lower picture. If you have any questions you can email me. HTH

Keith & Shawn(Gold Medal Winner)








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Sorry forgot to put my email in.

Keith