SS bolts on JS/WP pulley?

Thomas95SC

Registered User
I was looking at getting new bolts for the waterpump and jackshaft pulleys when I noticed that they offered stainless bolts. I believe the stock bolts are grade 5 5/16-24. Wasn't sure if they were good enough to use in place of stock bolts.
 
They are surely metric. I'd guess 8mm.

If they are AL pullies, then I would stick with the steel bolts. If they are steel pullies then it doesn't matter.
 
Yes the thread is 5/16-24. I used nickel plated steel bolts and they look great still after a few years.
 
So basically I should stick with steel bolts? The jackshaft will be the stock steel one for now but I will be installing the aluminum underdrive pulleys.
 
Stainless is not as strong. Like I mentioned just get nickel plated steel bolts they look good on aluminum pulleys.
 
Does anyone believe that a stainless bolt will break when being used as a JS or waterpump bolt? I would have to think that if they shear off, you've got bigger problems.
 
Stainless is not as strong. Like I mentioned just get nickel plated steel bolts they look good on aluminum pulleys.

True but for grade 5 its only a 14% difference (85000PSI v. 740000PSI)

Personally after changing the water pump on mother-in-law's 351w I suggest going to studs instead of bolt. It made putting the pulley and clutch fan on a whole lot easier.
 
You will get dissimilar metal corrosion between al and 300 series SS. Nickel is a good choice for all but magnesium.

5/16 and 8mm are really close. I'd still bet they are 8mm bolts.

Neither of these probably matters much though.
 
You will get dissimilar metal corrosion between al and 300 series SS. Nickel is a good choice for all but magnesium.

5/16 and 8mm are really close. I'd still bet they are 8mm bolts.

Neither of these probably matters much though.

Not any more than you get with aluminum and steel, just a good reason to use anti-sieze on the bolts.

You'd lose the bet, they are definitely 5/16"-24.
 
Not any more than you get with aluminum and steel, just a good reason to use anti-sieze on the bolts.

You'd lose the bet, they are definitely 5/16"-24.

I believe the threads are M8-1.25. The whole car is metric, and I have yet to find one bolt that isn't.

Fraser
 
I believe the threads are M8-1.25. The whole car is metric, and I have yet to find one bolt that isn't.

Fraser

Go check, I just installed the bolts in my WP and JS pulleys this week.

And, while you're at it, check the diff cover bolts, they are 5/16"-18. ;)
 
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5/16 * 25.4 mm / in = 7.9375 ~ 8mm Try using an 8mm socket on a 5/16 bolt, or vice versa, I can't tell a difference.

1 in / 24 threads = 0.04166 in * 25.4 mm/in = 1.05833mm ~ 1.0mm pitch

8 X 1mm which (acording to mcmaster car) is the standard coarse pitch.


I bet you can find some 5/8 bolts on the car too (or 16mm).



Regardless, I don't think it matters what you use.
 
I've only ever used metric tools on my car and I have never stripped a bolt or nut yet, and they have always fit snuggly ;).

Fraser
 
I've only ever used metric tools on my car and I have never stripped a bolt or nut yet, and they have always fit snuggly.

What does this have to do with thread pitch?

M8x1.0 is metric fine thread, M8x1.25 is metric coarse both regardless won't work.
 
Ok 1 more, then I'm done lol.

7.9375mm is .0625mm off from 8mm or 0.00246" difference
1.05833mm is .05833mm off from 1.0 or 0.00229" difference.

What's the tolerance on those bolts? better be less than +/-.003", otherwise we are both right :):p


5/16 * 25.4 mm / in = 7.9375 ~ 8mm Try using an 8mm socket on a 5/16 bolt, or vice versa, I can't tell a difference.

1 in / 24 threads = 0.04166 in * 25.4 mm/in = 1.05833mm ~ 1.0mm pitch

8 X 1mm which (acording to mcmaster car) is the standard coarse pitch.


I bet you can find some 5/8 bolts on the car too (or 16mm).



Regardless, I don't think it matters what you use.
 
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