Greg5OH

Now that sewell lexus doesnt do parts, I dont have a torque reference!
Anyone know what the spec is on the fine thread M12 socket head cap screws that hold the CV shaft to the Diff stubs? 6 bolts in total. They were HARD coming out. Im guessing around 75 ft lbs?

thank you!.

dicer

The bolt diameter would need to be at least 13 mm diameter, that is the threaded end, to be torqued that high and even then that maybe too high for a fine thread.
They may have had a medium strength locktite that would make them feel tighter. I don't have the spec handy.
If it was a coarse thread English or fractional and had a 1/2 inch hex that would be a 5/16 bolt they torque at around 20 ft lbs. 5/16 is 7.9 mm at the thread end. I would guess not over 20.

Greg5OH

way, way way over 20 foot pounds. I agree could have had a threadlocker (i will certainly be applying some either way). There is a good amount of compression in the joint. Even after getting the initial crack on the bolt (1 foot breaker bar, took probably a good 80-100 foot pounds to crack them) still took about half a turn for them to loosen off completely to hand thread them out.

Its an m12 socket head cap screw . I know this because it takes a 10mm male hex drive, as well as I measured the fastener. 12mm diameter body.

I would be money that 25 foot pounds would get next ot no clamping force on that joint. a grade 12.9 bolt will require a higher torque than a 9.8 because it is resistant to stretching and thus clamping.

Charts show a dry gr 12.9 M12 should be installed at 12 foot pounds. Which it felt like 100 or so at breakaway.




In this case I am guessing install is somewhere around the 120 foot pound mark. Installed dry.

timmy0tool

iTrader: (7)

i would always just refer to the FSM. i know there are folks here with access to one, and unfortunately i am not one of them . over time with age, temperature fluctuations, road salts/debris, etc the bolts would be hard to break initially but they may have been initially torqued low from the factory.

GH5T

What does FSM stand for?? factory service manual????

aptoslexus

61 ft/lb, if this is what you're referring to.

dicer

It was guess work like I said. I did not know the size.

sha4000

iTrader: (1)

Yes..........

Greg5OH

Thank you, I ended up taking them to 75 last night before reading this, close enough.

333mattlong

61 ft lbs but shold i use lock tight?

fondu

Interesting choice of thread to revive after almost 9 years.

Do not use loctite. The manual recommends to put a light coat of engine oil on the bolts. Quite the contrary to loctite.