4x4Wire's TrailTalk Forums: Crank Pulley Bolt Broken

For the archives...

I should have listened to the Mitsu parts-counter guy. When asked how to remove the broken crank damper pulley bolt, he says: "You don't. Call the guy at Allied Machine Shop and pay him $250. You'll never get it out."

Of course, I had to try. For the record, here's the carnage:

Bolt:

Initial "Inspection Mirror" shot of crank:

After the break, I gave the area several liberal douses of PB-Blaster over the next few hours, and let it soak over night.

So... attempts to drill it out via my drill, and a right-angle adapter produced the following:

- Several dull drill bits (which I had to cut the shank off on in order to get to clear the radiator)
- A right-angle drill adapter with a melted casing and stripped gears
- Sore and bruised hands and ribs
- Enough progress to thread a #4 Easy-Out in to the bolt

Gradually increasing the force with which I attempted to turn the Easy-Out of course simply broke the Easy-Out.

Have I mentioned that Easy-Outs are incredibly hard?

At this point I've realized that I'm going to have to go thru the front. This involves the fun of:

- Draining the coolant
- Removing the front grill
- Removing the center support/latch/horn bracket assmbly (lots of bolts)
- Removing the fan assembly
- Removing the radiator (along with water and tranny hoses)
- Evacuating the freon from the A/C system
- Removing the A/C condensor (oof major PITA)
- Loosening the tranny cooler & lines
- Loosening the oil cooler

Here's what it looks like when all of that is gone (if you look closely, you can see the 'dull' spot in the center of the broken-off-crank-bolt... that's the broken easy-out):

Look at that shiny water pump!!

Several more hours, titanium drill bits, torch-heat application, and Dremel-tool grinding stones later, I was able to thread a #5 Easy-Out (the largest I could find) in there. Of course it broke too.

My buddy later broke yet another #4, and ground most of it out as well:

Eventually, I realized I wasn't gonna get it myself, and called in the reinforcements:

He had a awesome selection of carbide brinding tools, custom chisels, and metric long-bore taps. 90 minutes and $325 later he had it out. Some thread damage occurred, but there was still enough to hold over the 137 foot-pounds of torque the new bolt required.

My favorite quote from him: "You don't drill out easy-outs. You grind them." I must say I agree.

In the final analysis, a few things:

1) It would appear that somebody removed the pully before, and re-used the bolt but used a bunch of some sort of thread sealant. You can kind of make it out in the picture below, and it was evident that it had dripped out on to the large washer when it had been tightened down last.

2) Mitsubishi has changed the part number for this bolt, and the metal on the new bolt is different in appearance. Perhaps this has been an issue previously. (Or is related to the issue on the earlier model crank bolt problems?)

3) The bolt comes from the factory with some thread sealant already on it... I would recommend springing the $4 for a new bolt (and washer, actually... they deform a bit to hold the torque) if ever removing. I would avoid additional thread sealant.

4) Don't over tourque!

5) Be EXTREMELY careful using the "starter trick", or even how you manually attempt to remove the bolt. As you can see in the picture above, there is a "collar" on the bolt that seats on the pulley/washer, which is the clamping surface. The additional length to the head of the bolt is just to extend the bolt head out the front of the pulley depth so you can get to it. The end result of this is that any off-axis torque is multiplied along the bolt shaft. Given that long breaker bars are likely in this operation, there can be a LOT of lateral force exerted on the bolt shank. Be very careful about right-angles on your breaker bars, and fully seating your sockets.

And call the machinist early on.

--------------------
-Steve
-1995 Montero SR 3.5L V6 DOHC

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