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Re-use bolts on PP & FW ??

really ????? grade 5 bolts for installing a clutch and pressure plate -- somebody may have went to class for nut and bolt tech but they were not listening --- factory used grade 8 --- if you want to use grade 5 bolts in this application -- the next time you take your car out for a ride get a grenade ,pull the pin out and jam the arm under the console or seat -- believe me you are not going to hear any clunking before it lets go.
look up clutch explosions on you tube.
Google shear strength of grade 5 vs grade 8. Grade 8 has greater tensile strength but weaker shear strength.
 
what fran said
proper torque for each tho
ugh
is factory torque for 5 or 8
 
my 73 book shows for grade 5 bolts 3/8 30LB grade 8 would be 42LB
 
right
sing gr 8 and gr 5 torque gives no bolt stretch and no clamp
torquing to gr 8 s really wrong into trans or water pump etc
and will overcompress gaskets
use right bolts and right torque
right Fran
 
right
sing gr 8 and gr 5 torque gives no bolt stretch and no clamp
torquing to gr 8 s really wrong into trans or water pump etc
and will overcompress gaskets
use right bolts and right torque
right Fran
@Bbcharger500 gets the credit on G5 bolts. Was told that many years ago but I failed to remember it.
 
@Bbcharger500 gets the credit on G5 bolts. Was told that many years ago but I failed to remember it.

Factory and Aftermarket all use Grade 8. I just double checked my supply room and have factory and aftermarket and ALL of them are grade 8.
 
Been a long time since pulling a stock stick setup apart but from what I remember, they were grade 8....at least on the crank/flywheel bolts. Also, the correct name for these fasteners are 'cap screws' and not bolts. Bolts usually entail a stud and two nuts. :D Also went to a nuts and bolt class and is where I found out that it's the nut that loses it's torque ability after the first tightening by a large margin. Take it off and then reuse it with the same torque reading and the clamp force won't be the same and a cap screw doesn't loose nearly as much clamping force.
 
Torque on clutch cover 3/8's bolt takes in SM is 30 foot lbs.. This bolt torque chart grade 8 thkes 33 foot lbs and grade 5 takes 23 foot lbs both course thread. So I'd say grade 8 for clutch cover.
torq.JPG
 
Shear strength is proportional to tensile strength. 60%

Every flywheel and pressure plate bolt that I've used has been grade 8. That's a lot of years, and a lot of bolts

Plus they are purpose specific. They both have shoulders.
 
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