A BROKEN CRANKSHAFT BOLT

arrgh .....

What's wrong with this picture?
1. Worn Keyway
2. Holy cow, the crankbolt
is broke!

It was an awful moment. When I began to remove the crank bolt, it was finger tight and easily spun a half turn , allowing the pulley to move with the slop in the keyway. After two more turns, it tightened up. I should have just rocked it back and forth, but being impatient, I hooked on a two foot breaker bar and the bolt head snapped off. Was it time to look for a replacement engine?

THE LAST HOPE

This is a screw extractor. It's inserted into a
hole drilled into the body of the bolt. It jams
against the sides of the bolt when twisted
counterclockwise. If all goes well, the bolt
comes out.

This job looked especially difficult. I would have to drill a hole into the remainder of the bolt shaft, keep it more or less parallel with the shaft, and then get enough force with a screw extractor to back it out. The one thing I wanted to avoid was breaking off the extractor inside the bolt. They're made of hard steel and are almost impossible to drill out if broken.

ELBOW ROOM

The radiator and AC condenser were in the way. The radiator was easily removed, but I didn't want to disconnect the AC plumbing. I took off the condenser mounting bolts and loosened some of the hose clamps so that the unit could lay on the garage floor.

With a brand new bit in my Craftsman drill, I made a starter hole in the bolt shaft. The metal was fairly soft. I then put in the 5/16" drill specified for my extractor tool and drilled almost to the end of the bolt.

THE BIG TWIST

The above pictures show the extractor hammered into the drilled hole and the setup I used to torque it. The original bolt with a 21 mm head had snapped off when I applied over 100 ft-pounds with a breaker bar. I was not very optimistic about getting that kind of force on the 1/4" head (6.2 mm) of the extractor. I looked in vain for a square 1/4" socket in the stores. Finally, I slipped the square drive end of a 1/4" socket over the extractor and tried different ways to grip it. The above shows my final setup. The 1/4 socket end grabs the extractor. A piece of hex stock between that socket and a second socket on a breaker bar allowed plenty of torque. I ripped two sockets apart and the bolt never budged.

I redrilled a smaller hole thru the bolt and sprayed the inside cavity with Liquid Wrench, hoping it would reach the threads from the back. I also sprayed the outside and let it all soak overnight. The bolt wouldn't move.
I heated the end of the crank, and sprayed the bolt with a freeze spray until it frosted over. Still stuck..
I heated the bolt and crank end with a propane torch until the edges of the bolt began to glow. Finally, it began to turn!

WOOHOO!

The above pictures show the removal process and the final success. I sure felt good. Note the burn marks on the outside of the crankshaft seal.

AFTERMATH

Inspection showed a small burr on one of the threads and also some rust. The latter was the reult of the previous mechanic reusing this bolt. I don't know how the burr got there, but it sure jammed things. I had to recut the threads in the crankshaft. This made the new crank bolt fit a little looser.

So that's the end of this tale. I've owned a set of Craftsman Screw Extractors for years, but this is the
first time I ever used them successfully.