Help - Broken Coil Pack Bolts

J

John308

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This is my first post here, but I've been doing a bunch of reading over the last several months. You guys have a great forum with lots of great info. I bought a 96 SR5 4x4 with rear locker and about 150k on the odo, and I've been slowly going through it over the last few months.

Today I decided to do plugs and wires, and I ran into a problem that I was hoping someone could shed some light on. When I went to unscrew the coil packs, the bolt heads on two of them snapped off. I was using a 1/4" drive ratchet, and it hardly took any force for the bolt head to twist off. After doing it to the first one, I sprayed the stub with PB Blaster to let soak, and I figured I'd just finish up the other two while it was soaking. When I went to do the second one, that bolt head twisted off too. I'm wondering if anyone has any ideas on why this would happen. Looking at the bolt shaft, there is a white residue at the base of the threads that looks like either some type of thread locker, or maybe some sort of corrosion.

I tried putting a set of vice grips on the first one, and it isn't budging at all. Does anyone have a better way to unscrew them? Thanks for any advice, and sorry for the long post.
 

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John308 said:
This is my first post here, but I've been doing a bunch of reading over the last several months. You guys have a great forum with lots of great info. I bought a 96 SR5 4x4 with rear locker and about 150k on the odo, and I've been slowly going through it over the last few months.

Today I decided to do plugs and wires, and I ran into a problem that I was hoping someone could shed some light on. When I went to unscrew the coil packs, the bolt heads on two of them snapped off. I was using a 1/4" drive ratchet, and it hardly took any force for the bolt head to twist off. After doing it to the first one, I sprayed the stub with PB Blaster to let soak, and I figured I'd just finish up the other two while it was soaking. When I went to do the second one, that bolt head twisted off too. I'm wondering if anyone has any ideas on why this would happen. Looking at the bolt shaft, there is a white residue at the base of the threads that looks like either some type of thread locker, or maybe some sort of corrosion.

I tried putting a set of vice grips on the first one, and it isn't budging at all. Does anyone have a better way to unscrew them? Thanks for any advice, and sorry for the long post.
Click to expand...

yep, just corrosion.

get a small butane, or propane torch. heat the bolt, then let it completely cool. then heat the area around the bolt, where it threads in. while that is still hot, use the vice grips. the bolts should come right out.
 
nevada said:
yep, just corrosion.

get a small butane, or propane torch. heat the bolt, then let it completely cool. then heat the area around the bolt, where it threads in. while that is still hot, use the vice grips. the bolts should come right out.
Click to expand...

Then be prepared for a nasty shock as you look at plugs with 100k+ miles on them. If three are NGK on one side and three Denso on the other, they are likely factory original.

I change mine every 30k, use anti-seize and torque to spec. They always come right out.
 
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Also use anti seize on the coil pack bolts when you replace them. Steel bolts in an aluminum valve cover causes electrolysis and causes the corrosion because of the different metals. I used anti seize on everything going into aluminum when I did my head gaskets.
 
Thanks for the suggestions. I tried heating up the bolt stub and then letting it cool, then heating the valve cover around the bolt. It didn't want to turn at all. I ended up going to the hardware store and buying some threaded rod connectors. I put them in my little hobby lathe and turned down about 3/4 of the length so that the outer diameter of the connector matched the inner diameter of the hole in the coil pack. I then used it like a hollow bolt to tighten down the coil packs.

I ended up making three of them, since the bolt on the third coil pack snapped just like the first two. I posted a pic down below of what it ended up looking like.
 

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Modifying a threaded rod coupler into a sleeved nut fitting. That's a first for me. Pretty cool man.
 
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