!?!?!?! Driver Rear Body Mount Bolt

[ShadowsPapa]

I think that extreme heating of the bolts, torque to turn them against red loctite, etc. can weaken them enough that they can fail, as ShadowsPapa found. I don't try to reuse them, but replace them with grade 12.9 Allen heads and thick hardened washers. I choose the lengths and washer thicknesses so that they stay within the range of threads. These replacement bolts have shorter thread ranges than the stock bolts, so lengths are critical. The Rock Hard sliders have 3/8" thick flanges and I used these lengths and washers with the Allen bolts:
M12x1.75x100 with 0.11" thick gold-plated washer and 0.19" thick black washer in front, M12x1.75x120 with 2 gold and 1 black washer in the middle, and M12x1.75x220 with 1 gold and 1 black in the rear positions. I applied high pressure chassis grease for uniform torque applications and to prevent residual loctite from interfering. I got the bolts and washers from McMaster, except the thick black washers which came from Rock Hard. I did not use the grade 8.8 Rock Hard bolts as they would be weaker than the stock 10.9 bolts (110,000 psi, 150,000 psi, and 170,000 psi strengths for 8.8, 10.9, and 12.9 grades).

For most, I didn't have to use that much heat - actually a propane torch did 3/4 of them but if you have to use much heat, you've probably changed the bolt, and new would be smart.
The number of threads involved on the factory bolts it just plain crazy - I suppose they figure the bolt can back out for weeks and not get lost, but then most of mine had retainers on them so if the bolt came completely loose, it could not be removed from the hole. So why the extra 3/4 of threads sticking up above the nut?

I sort of wonder if Jeep's documents don't show those as single use bolts...
Nope, guess not - just new thread locker............ if you are going that far, why not replace the bolts if they required a lot of heat and a lot of work to remove.

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[jmdwifi]

For most, I didn't have to use that much heat - actually a propane torch did 3/4 of them but if you have to use much heat, you've probably changed the bolt, and new would be smart.
The number of threads involved on the factory bolts it just plain crazy - I suppose they figure the bolt can back out for weeks and not get lost, but then most of mine had retainers on them so if the bolt came completely loose, it could not be removed from the hole. So why the extra 3/4 of threads sticking up above the nut?

I sort of wonder if Jeep's documents don't show those as single use bolts...
Nope, guess not - just new thread locker............ if you are going that far, why not replace the bolts if they required a lot of heat and a lot of work to remove.

I attempted to install yesterday. I heated the rear drivers side bolt because I figured might as well do the nightmare bolt first. It came loose and I unscrewed it all the way but it would not come out. It was unthreaded and I pulled hard as I was turning but it just spun. I pushed it back up and it it threaded back in the nut no problem. Unscrewed it again twice but it just wouldn't come the rest of the way out. Then, BAM, my son-in-law shows up with my grandson and of course we babysat. He had to go to work. I tightened the bolt back up and just snugged it. I may try again tonight.

 

[ShadowsPapa]

I attempted to install yesterday. I heated the rear drivers side bolt because I figured might as well do the nightmare bolt first. It came loose and I unscrewed it all the way but it would not come out. It was unthreaded and I pulled hard as I was turning but it just spun. I pushed it back up and it it threaded back in the nut no problem. Unscrewed it again twice but it just wouldn't come the rest of the way out. Then, BAM, my son-in-law shows up with my grandson and of course we babysat. He had to go to work. I tightened the bolt back up and just snugged it. I may try again tonight.

It's got a keeper on it, it's "captured". There's a piece that the bolt goes through that's sort of a one-way trap. You'll have to pull REALLY hard to get that bolt out of it.

I thought I had a picture, but can't find it. It's like a washer with teeth. At least some of mine had that.

 

[jmdwifi]

It's got a keeper on it, it's "captured". There's a piece that the bolt goes through that's sort of a one-way trap. You'll have to pull REALLY hard to get that bolt out of it.

I thought I had a picture, but can't find it. It's like a washer with teeth. At least some of mine had that.

I understand exactly what you are talking about. Thank you and with that confirmation, I may take another stab at it tomorrow night. Got home late from work. Thank you again.

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