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harmonic balancer install of doom

XJLI

XJLI

NAXJA Forum User
Location
Long Island, NY
well, i managed to gt the old one off, get the new one half on sideways, get it off, get the installer bolt stuck inside the crank, loctite a bolt in that bolt, get it out, this morning i packed a bag of ice on the crank, ground down the key a tiny bit with a dremel, and let the pulley sit in my sink filled with water i boiled for a while. i managed to man-strength the pulley onto the crank and get it on straight. then i started using the installer tool from autozone...

the installer thing slipped out of the crank AGAIN when i was tightening it (happened two days ago as well). so, i followed advice from an old guy who was a mech for like 40 yrs and he said just use the crankshaft bolt to press it on. too bad i need about 1/4" more til the threads engage. so, i did what any normal person would do in that situation and threw a wrench across my street, then rode my bike to the hardware store to get a longer one. i get there and am having a hard time finding the right size with the fancy bolt size-o-meters and one of the older 'i know everything about nuts and bolts' guys comes over and helps me out. hes having a hard time figuring it out. now two guys are helping me and they both determine its a half-size metric bolt. probably a 13.5mm thread. wonderful.

what that means to me is there is a small possibility grainger carriers one, and a small possibility fastenal does. and since i've been using a 12mm thread on the installer, there is also a possibility my crankshaft is stripped out. i can thread the bolt in a bit (w/o the washer) but cant go much further bc the pulley is in the way.

i have no idea what to do next.
 
Kinda been there, done that.

While replacing a balancer on a 4.0l I have on a stand, I managed to pull the threads right the heck out of the end of the crank. It's Helicoiled now. Fortunately, I did have the luxury of some time to work on it, it took a couple of days to get the right set.
 
No reason it won't, as long as you do a good job of cutting threads. Big reason I went with a Helicoil was that I do plan on selling the engine, and keeping it the stock size seemed to be a good idea.
 
Wait a sec........ that *IS* a fine thread bolt, IIRC. 1/2"x20 does make sense.

If you plan on a simple drill & tap, you must go bigger than the original size. Drill size needs to be big enough to completely remove all of the old threads to leave a smooth bore.
 
FWIW - 13mm and 1/2" are very close...

and the AMC motor likely has a standard thread in the crank...

grab a 1/2 - 20 bolt and see if it threads in... I remember using something to that effect when I put on on...
 
I was just getting ready to say that the threads on my '85 2.5 were 1/2-20. When you mentioned the metric, I assumed they had changed them for the 4.0.

The first time I did mine I managed to screw up the end threads with the puller but was able to successfully chase them with a 1/2-20 tap. I guess the success of this would depend on how many threads you pulled out.

When installing the new balancer, I bottomed the long starter bolt out without realizing it. I don't know how close I came to twisting off the bolt with a good long cheater but it still scares me. I doubt that anyone else is going to be that dumb but thought I would mention it for those getting ready to start this job.
 
there was enough meat left in there to salvage the threads, and my friend and i tapped the hole at 1/2x20. seems to be going smoothly now. thanks guys
 
For the love of god, don't strip the bolt trying to use it to press the balancer on like I did. Just go out and rent the harmonic balancer installer tool from Autozone (part #27144.) It took me 15 minutes to get it back together after I had stripped two of those 1/2" bolts and some of the threads inside.

The tool has a bearing that keeps the motor from spinning and the heavy duty threads won't strip while you crank on them with a 32 mm wrench. I was able to salvage the job once I had the right tool.

I did have undo the transmission mount from the crossmember and jack up the transmission to get the tool to fit into the motor, but I didn't have to remove the radiator or the fan.

normal_image~121.jpg
 
Hope my tool didn't mess you up. When Cal asked if you could borrow my harmonic balancer tool, I said yes. A while later, I was thinking, "I don't have a harmonic balancer tool". He must've given you my steering wheel puller.
 
Pelican said:
I was just getting ready to say that the threads on my '85 2.5 were 1/2-20. When you mentioned the metric, I assumed they had changed them for the 4.0.

The first time I did mine I managed to screw up the end threads with the puller but was able to successfully chase them with a 1/2-20 tap. I guess the success of this would depend on how many threads you pulled out.

When installing the new balancer, I bottomed the long starter bolt out without realizing it. I don't know how close I came to twisting off the bolt with a good long cheater but it still scares me. I doubt that anyone else is going to be that dumb but thought I would mention it for those getting ready to start this job.
Click to expand...

I feel your pain, and I appreciate the post as I am about to tackle this in a few days. Fortunately I have the engine out,on a stand, and no rush to get it done.

Thanks again.
 
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