Bolt choices

[Green66Shortbed]

i have a 66 c-10 that i am replacing the clutch in, (along with the motor) and im wondering if anybody knows if it makes a difference whether or not i use the original style bolt that has a shoulder or if i can use one that is threaded all the way up to the head.

im referring to the bolts that hold the clutch assembly onto the flywheel.

[Chevy Fleetside]

You want it to be at least a Grade 8 bolt.

[Green66Shortbed]

Originally Posted by Chevy Fleetside

You want it to be at least a Grade 8 bolt.

see, thats the thing, i can use the bolts that GM gave me or the ones i have.

the GM bolts dont look like grade 8 bolts, but they have a shoulder, and the bolts i have are grade 8 bolts but they dont have a shoulder. decisions, decisions.

[Green66Shortbed]

bump

[ray-bones]

use the shoulder bolts. find them in a grade 8 if you can.

[Green66Shortbed]

Originally Posted by ray-bones

use the shoulder bolts. find them in a grade 8 if you can.

i am currently replacing the clutch in my grandpas truck and we can use either bolt. i replaced the clutch in my truck and didnt use a shoulder bolt. i did use a lock washer, though.

is there any reason that a bolt that was threaded the full length couldnt be used in this situation? if it gets torqued to 45 lb ft it wouldnt be any different than a shoulder bolt, right?

[joe231]

I don't know why those are shoulder bolts, the clutch pressure plate assembly should be tight against the flywheel.
if it were me I would just use fully threaded grade 8 bolts....

[Green66Shortbed]

Originally Posted by joe231

I don't know why those are shoulder bolts, the clutch pressure plate assembly should be tight against the flywheel.
if it were me I would just use fully threaded grade 8 bolts....

way to go, joe. this is the answer i really wanted to hear. if it were the other way i would have to tear my truck apart again and use the different bolts on my clutch assembly. i dont want to do that.


THANKS TO EVERYONE!!!!

[joe231]

do I win a prize?

hopefully, for your sake and mine, it is the right answer

[Green66Shortbed]

Originally Posted by joe231

do I win a prize?

hopefully, for your sake and mine, it is the right answer

well, if it isnt, we will find out soon enough. its almost ready to hit the road.

i should really start a build thread.

[502tripower]

A Shop Manual is a must if you plan on doing any work on these old rigs. This should answer your question. As My Auto shop teacher Merv Hall use to say. "These automobile manufactures have spent thousands of dollars on research and development. What makes you think you can do any better". And of course we would just laugh and continue with our work. Anyway what I am getting at is use the shop manual and the Assembly Manuel. These will give you the correct information.

[Captainfab]

Before I knew any better I used regular fully threaded bolts without issues. The factory bolts have the shoulder on them so that the torsional force from the pressure plate is against the smooth shoulder instead of against the threads on a fully threaded bolt.

[joe231]

Ah, makes sense guys.
Thanks

when The OP was saying shoulder bolt I was thinking it would bottom out and allow the pressure plate to float, which I don't think would be a good thing.

[Green66Shortbed]

well with this new found knowledge, it looks like the trans and bell housing will be coming back off in the next few days. at least i found this out before i was cruising down the highway. lol. i do love the learning experience, though. thanks to all you you for your help. this place is awesome.

[MacAttack]

Stress risers (including threads) under shear are not good things. Threads are to create compression load. Shoulders take shear much better.

[Tx Firefighter]

Originally Posted by Green66Shortbed

well with this new found knowledge, it looks like the trans and bell housing will be coming back off in the next few days. at least i found this out before i was cruising down the highway. lol. i do love the learning experience, though. thanks to all you you for your help. this place is awesome.

No sense going to that much trouble. Just turn the engine around as needed and change the bolts one at a time through the bottom of the bellhousing. No need to remove the bellhousing or trans.

[Green66Shortbed]

Originally Posted by Tx Firefighter

No sense going to that much trouble. Just turn the engine around as needed and change the bolts one at a time through the bottom of the bellhousing. No need to remove the bellhousing or trans.

this, right here, is why i come here. *high five* is it an acceptable practice to just remove one bolt at a time and place a new one in there? should i remove them all and then reinstall and follow the pattern?

[Tx Firefighter]

Do them one at a time and you will be fine. You might take a big c-clamp and cinch it down near each bolt to keep the pressure plate from warping away from the flywheel when you get the bolt removed until you get it replaced.

If it were mine, I wouldn't even do that though.

[joe231]

good idea

[Green66Shortbed]

Originally Posted by Tx Firefighter

Do them one at a time and you will be fine. You might take a big c-clamp and cinch it down near each bolt to keep the pressure plate from warping away from the flywheel when you get the bolt removed until you get it replaced.

If it were mine, I wouldn't even do that though.

wouldnt bother using a c-clamp or replacing the bolts at all?

it wont be a problem to remove a bolt and torque it, then skip a bolt, remove the next one, replace and torque, skip, remove and torque, and so on, or would can that potentially cause some trouble?

[502tripower]

Originally Posted by Green66Shortbed

wouldnt bother using a c-clamp or replacing the bolts at all?

it wont be a problem to remove a bolt and torque it, then skip a bolt, remove the next one, replace and torque, skip, remove and torque, and so on, or would can that potentially cause some trouble?

One at a time will work just fine. Good Luck.

[ChiefRocka]

I dont think its that crucial in using a "shoulder" bolt in this application. On my clutch I used a 3/8" x 1" grade 8 bolt, washers and Locktite.

If you must run a shouldder bolt, you can but longer bolts (so you have a shoulder) then cut them down.

However, all you would need is an 1/8 shoulder...mabey 1/4 at the most.

[joe231]

if the smooth portion is much longer than 1/8th" seems it would interfere with the clutch tightening to the fly wheel, which would be much worse than using a entirely threaded bolt, if the pressure plate assembly were allowed to float i would assume it would eat the bolts and wallow out the holes in a very short period, not to mention make some noise....

[Green66Shortbed]

Originally Posted by ChiefRocka

I dont think its that crucial in using a "shoulder" bolt in this application. On my clutch I used a 3/8" x 1" grade 8 bolt, washers and Locktite.

If you must run a shouldder bolt, you can but longer bolts (so you have a shoulder) then cut them down.

However, all you would need is an 1/8 shoulder...mabey 1/4 at the most.

the grade 8 bolts i have on my clutch currently have about an 1/8 shoulder i think. i bet they are the exact same as the ones you used. how long have you had your clutch on your truck? noticed anything different?

[Green66Shortbed]

Originally Posted by joe231

if the smooth portion is much longer than 1/8th" seems it would interfere with the clutch tightening to the fly wheel, which would be much worse than using a entirely threaded bolt, if the pressure plate assembly were allowed to float i would assume it would eat the bolts and wallow out the holes in a very short period, not to mention make some noise....

the shoulder doesnt interfere with the tightening of the bolt, nor does it let the clutch assembly float. i think its there for the clutch assembly to sort of ride on in a way. rather than only touching a thread on the side of the hole, there is a solid surface. somebody mentioned this earlier, i think.

the flywheel is threaded completely through it so the bolts can tighten as much as they need to. there are only less threads being used since the shoulder is about 3/8 of an inch long. that would make me think that i would want to use a fully threaded bolt rather than a shoulder bolt since i would have more threads working to hold the pressure plate to the flywheel.