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  Topic Review (Newest First)
07-25-2021 06:20 AM
fishadventure
Quote:
Originally Posted by bpounds View Post
Quote:
Originally Posted by Waternut View Post
I think you'll have more issues trying to find quality metric bolts of equivalent strength than you will reusing the old ones.
Pretty sure the 4.2 has all SAE bolts. The motor brackets were either 5/16 or 3/8 NC.
Yes.

As far as replacing non-motor bolts: I’m confident that other than spring ubolts, ujoint straps and bolts, and (dubiously) ujoint flange bolts there are no torque-to-yield bolts on a YJ outside the motor/driveline internals.

Secondly, unless your use ARP or other high-grade US or German brand the oem AMC and Chrico bolts are WAY better quality alloys and have the right ‘flange’ on cap bolts and nuts as compared to the hardware store or tractor supply. It’s not just what you see, it’s in the alloy and heat treat- what you can’t see. The oem AMC nuts and bolts in particular are very good alloy.

If you cleaned them and if paranoid used blue threadlocker they’ll be fine.
07-22-2021 02:11 PM
Waternut Makes sense. I was just basing that off the 2.5L engines I worked with and I think those were 12mm because mine were messed up and 1/2" bolts wouldn't fit.
07-22-2021 10:49 AM
timatoe
Quote:
Originally Posted by jbolty View Post
right, don't think there was anything metric until the 4.0
Could be mishmashed parts, but "most" everything on mine is SAE but some oddball stuff like power steering pump bolts are 15mm.
07-22-2021 10:08 AM
jbolty
Quote:
Originally Posted by bpounds View Post
Pretty sure the 4.2 has all SAE bolts. The motor brackets were either 5/16 or 3/8 NC.
right, don't think there was anything metric until the 4.0
07-22-2021 09:41 AM
bpounds
Quote:
Originally Posted by Waternut View Post
I think you'll have more issues trying to find quality metric bolts of equivalent strength than you will reusing the old ones.
Pretty sure the 4.2 has all SAE bolts. The motor brackets were either 5/16 or 3/8 NC.
07-21-2021 08:09 PM
Boojo35 Torque to yield bolts and bolts that need to be replaced during a procedure has become dirty business IMO. Sure, some need to be replaced for sure. But, if a manufacturer puts a replacement footnote in some obscure place and that particular bolt replacement is not documented on a repair order it shifts or potentially shifts liability in stupid effing ways. This industry has become retarded.

If they are clean bolts, good threads, screw in an out with fingers, not rusty, and do not look distorted or thin in places. Reuse them.
07-21-2021 02:45 PM
Waternut I think you'll have more issues trying to find quality metric bolts of equivalent strength than you will reusing the old ones.
07-21-2021 09:24 AM
bpounds I think it is the 2.5 that has repeated issues with the motor mount brackets. Not really an issue on the 4.2, and as long as the original bolts are in good shape I say reuse them.
07-20-2021 07:16 PM
timatoe I re-used mine 15 years ago, they're still there.
07-20-2021 06:00 PM
jimsahm
'89 YJ Motor Mount Bracket Bolts

Question: I re-installed and torqued to FSM value the engine bracket bolts (ones that hold brackets to the block). I read elsewhere to get new hardware and to not reuse the bolts. Any opinion if I should replace bolts or roll with it? Just re-installed engine (rebuilt 4.2L) and reused the old mount bolts.

Thoughts?

Thanks,
Jim

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