Five speed correct drive shaft bolt specs

[Vinnyz]

I've searched unsuccessfully for the correct specifications for the 5-speed drive shaft bolts.
I found mine to be in poor condition and not a shoulder bolt style which was always common on my s30 Z's.
Can I just assume it's a grade 8 shouldered with minimum length and be good?
Thanks for your links or help!

[JT68]

Regular grade 8 SAE 5/16" bolts are perfect. Lock washers of course. Lock nuts are great too but more tedious to remove. J

[Vinnyz]

Regular grade 8 SAE 5/16" bolts are perfect. Lock washers of course. Lock nuts are great too but more tedious to remove. J

Thank Jt. So they aren't spec'd for a shouldered bolt ?

[mraitch]

i think it makes a difference which way you put the bolts in (from a safety viewpoint) - the nuts should be on the 'outside' the bolt heads being on the 'inside' so that they are less likely to fall out if the nut unscrews.

[JT68]

Regular grade 8 SAE 5/16" bolts are perfect. Lock washers of course. Lock nuts are great too but more tedious to remove. J

Thank Jt. So they aren't spec'd for a shouldered bolt ?

Right, standard bolts are just fine. Nothing special like later cars. I do like lock nuts. It is rare for the bolts to loosen, but you are on the side of the road if they do. Cheap insurance. J

[fj20spl311]

It is rare for the bolts to loosen, but you are on the side of the road if they do. Cheap insurance. J

May experience differs, so I use blue Loctite. I have always used fine thread - 5/16 x 24 grade 8 bolts.

[spyder]

It is rare for the bolts to loosen, but you are on the side of the road if they do. Cheap insurance. J

May experience differs, so I use blue Loctite. I have always used fine thread - 5/16 x 24 grade 8 bolts.

Me too! I use the high strength Locktite and wave lock washers.

[JT68]

Same info, SAE is 5/16-24. Loctite is good, just a bugger to undo. Blue is fine, definitely not Red.

There is no rotational force trying to undo the nuts, only vibration. There is actually relatively little sheer force on the bolts if properly tightened. The clamping force is enormous, so friction between the mating flange surfaces is doing all the work.

If the fasteners loosen however, the bolts have it all, so again, grade 8 is good. Just don't forget to tighten well and definitely use lockwashers too!

[Vinnyz]

Same info, SAE is 5/16-24. Loctite is good, just a bugger to undo. Blue is fine, definitely not Red.

There is no rotational force trying to undo the nuts, only vibration. There is actually relatively little sheer force on the bolts if properly tightened. The clamping force is enormous, so friction between the mating flange surfaces is doing all the work.

If the fasteners loosen however, the bolts have it all, so again, grade 8 is good. Just don't forget to tighten well and definitely use lockwashers too!

Great, thanks everyone. I always use blue Loctite on my driveshaft bolts along with lock washers. I was stumped when the previous owner had such badly beat down fully threaded bolts still in place. No way I'd have reused them.

[Gregs672000]

Yes on the thread locker... I had my bolts loosen and I don't think I screwed up. Not anymore.

[Vinnyz]

Yes on the thread locker... I had my bolts loosen and I don't think I screwed up. Not anymore.

Always ......for sure! Vibration gremlins rarely happen when you have the right circumstances to explore or wrench.

I bought four grade 8 1.5" Partial thread yellow zinc bolts (washers and nuts too) and then cut them down to 1.0".

Here is the old vs. new.......



Here is the new bolts ready to be cut to 1.0".



Here they are just before torque down.....