Getting Ahead. Bolt. Out.

It's been driving me crazy for almost two weeks.

The Subaru engine is nearly all torn apart now, and the only obstacle standing between me and the head gasket replacement was the two bolts on the passenger side cylinder head.  They were stripped.

For the past two weeks, I've been trying to find some way to get them out.  It's been quite frustrating because every little trick that is supposed to work, didn't.  And I did quite a bit of research, trying everything I could find on the Subaru forums and the other car-repair websites. None of them worked.

The regular socket stripped out the heads.  The Bolt-Out from Sears stripped itself out.  Attempting to drill out the head with my regular drill bit sets only gave me a set of burned-out, dulled drill bits.  The screw extractor wouldn't even bite into the hole I'd drilled; in fact, it flattened the threads of the extractor!

Trying to cut the heads in half with a cold chisel didn't work; in fact, the metal was barely dented.  Obviously, something harder was needed.

So I went to the hardware store and bought two 5/16" drill bits, one Titanium and the other Cobalt, just to see what would happen.  With the Cobalt bit, I was able to drill a sizeable hole, finally, but couldn't get it any bigger, even when using larger drill bits.

Then I bought a pack of diamond-coated grinder bits for the Dremel and tried to expand the holes to the point where I could break them down.  That took nearly an entire day, and destroyed three of the four diamond bits.

Meanwhile, thinking ahead to the time when I'd be working on the second of the two bolts, I went out to Harbor Freight and bought a set of left-handed drill bits.  Because during my research, I was reminded that it was just possible to loosen up the bolt shaft if the drill was rotating in the same direction in which it is desired to rotate the bolt shaft.

Hmm.  That kinda makes sense.

But that wasn't going to work for the bolt head I'd already drilled & expanded, because it was already too big of a hole for the largest left-handed drill.  I'd have to keep trying with the Dremel bits and the cold chisel.

And, miracle of miracles, after I'd worn out three of the four diamond bits, one more strike with the cold chisel popped the top of the first bolt.

You can imagine my relief.

And I was relieved ... until I remembered that there was this other bolt that still needed to come out.

Sigh.

I really hoped that the left-handed drill bits would force the second bolt to move on its own and I wouldn't have to drill completely through the silly thing like had occurred with the first one.

So I started the second one with the left-handed drill bits, first a small one, then moving up the scale with larger bits to widen the hold.  But again, it got to the point where I had run out of left-handed bits and the bolt was still not moving, and the extractor bits weren't working.  I even tried the Titanium bit, but it didn't do anything other than turn blue at the tip.

Out of sheer frustration, I tried the Cobalt drill.  And ... POP! the entire bolt head broke off.

Kinda took me by surprise.

Loudly.  But pleasantly.

After all that work and struggle and sweat and worry, there it was.  Done.  Bolt heads broken off.  And the rest of the head extraction would be easy.

The bolt heads were off.  As pictured below.   And you can tell which one was the first "victim" of my extraction efforts because it's so raggedy-looking.  The second one looks nice and clean, comparatively. 

Bolt Head without Shafts

The cylinder head, once the other four bolts were take off, came right off, leaving the two "stuck" bolt shafts still on.
 And here's where things got weird.  You remember that it was impossible to rotate those bolt shafts, right?

Well, once the cylinder head was off, and the two shafts were sticking out into the open air, I took hold of them with my fingers and ... they were loose.  I was able to unloosen them with my fingers. 

Bolt Shafts Without Heads

Ain't that a kick in the head!


I can only surmise that the left-handed drill bits were able to loosen the bolts somewhat, but because I'd loosened up the other bolts so much, removing the tension they'd had against the cylinder head, all the tension was now being applied to the two remaining (stuck) bolts, which created a lot of friction between the bolt heads and the surface of the cylinder head.

That's also probably why the second bolt popped when it gave way, because it was holding all the tension by itself.

It was good to finally have the cylinder head off.

But, looking at all the tools that had been required to do the job, I was still a bit frustrated.  I'm hoping that enough of the learning curve has been climbed that it won't be necessary to do this again!

The set of tools it required...