Engine/Transmission (1994 - 1998) 5 Speed Flywheel Bolts - HELP!!!

[NMongeau]

Hey guys, I just swaped out my auto for an NV4500.

On the install I used a 13" South Bend CONFE clutch assy. The new flywheel didn't come with bolts and the factory bolts were on back order. I found bolts localy

12mm x 35mm, if I remember right. However the bolts that I used were a grade 5 equivelant. I just recieved the new bolts. Is it worth changing them or will the bolts in there be okay? Also the right bolts came with washers, is this correct?

Thanks for your help.

Neil

 

[BSmalley]

I would change the bolts if I were you. I know it's a PIA, but there's a ton of torque riding on those bolts! Just my two cents worth.

 

[GCroyle]

The bolts are grade 12. 9, metric. The best I can get at my local store is 10. 9, they are not the same strength.

 

[Woodenhead]

Grade 5 minimum properties:

Proof = 74,000 psi

Yield = 81,000 psi

Tensile = 105,000 psi



Grade 12. 9 minimum properties

Proof = 140,000 psi

Yield = 160,000 psi

Tensile = 177 psi



Grade 5 relative to 12. 9

Proof = 53%

Yield = 51%

Tensile = 59%



If they are supposed to be 12. 9 and you have the equivalent of Grade 5 which would be metric 5. 8 (worse than grade 5) or 8. 8 (a little better than grade 5 but not much) I say take the time and swap them out for the right ones. I'd hate to see the mess that you'd have if they sheared off. Until then, keep your foot out of it.



Mike

 

[NMongeau]

Thanks for your help. I'm still a little curious about the washers that the dealer sent me. Are those supposed to be used?

 

[GCroyle]

12. 9 original bolts are used with a "hardedned" washer on our F/W's, use em.



Nice job on the property comparison Mike, speaks VOLUMES!



Save one of the Grade 5's and cut the head off, put a slot in it, use it as a pin to hold the F/W for R&R, saves toes.

 

[98slushbox]

whats grade 12. 9? I'm assuming thats harder than a typical grade 8. I've just never heard of 12. 9. I need to find me some flywheel bolts.

 

[Woodenhead]

whats grade 12. 9? I'm assuming thats harder than a typical grade 8. I've just never heard of 12. 9. I need to find me some flywheel bolts.

12. 9 is a metric grade.

 

[GCroyle]

Dodge part number for F/W bolts, 6501680.

 

[98slushbox]

ah, i see. I guess thats about like a grade 8 standard. thanks fellas

 

[Dieseldemon]

Get them from Cummins part # 3901395

 

[98slushbox]

I cant remember, are they hex or allen head bolts? I can get them from work but couldnt remember what they were.

 

[Dieseldemon]

They are hex