propshaft bolts

[Captain Morgan]

ok, it has been recommended to me to replace the pain in the ass torx bolts with standard 6 point bolts. My question is, what threads are they?

I am 95% sure the rear bolts are 12mm x 1.75 with 25mm threads.
The fronts i "think" are 10mm x 1.50 with 25mm threads.

 

[Captain Morgan]

ok, i love replying to my own posts, what can I say. this is what i have researched so far.

rear bolts:
Grade 10.9
Hex Flange Head
Fully Threaded
12mm x 1.75 x 25mm

front bolts:
Grade 10.9
Hex Flange Head
Fully Threaded
10mm x 1.50 x 25mm

can anyone confirm this as correct?

 

[SY2932]

Yep, those are the specs for the front and rear prop shaft bolts. Your best bet of scoring them will be through a local machine shop. Just make sure that they are class (grade) 10.9 because the classification for metric and S.A.E. fasteners is different. I got mine from a huge industrial hardware supply warehouse by where I work. Tighten them to 70Nm or 52 ft lbs. when you install them. HTH's

Mike Campbell

 

[Makaveli]

Replacing those is a great idea. I just put mine in a few days back and those bolts will strip like it's there job. I only had problems with the rear ones, the extension I had on my torque wrench made it almost impossible to get the socket on the bolt completely straight. (so you may want to see if you can get the socket on the bolts all the way before you're underneath and realize your extension is to big) hope this helps.

invisibill sent me this.

http://www.techweasel.com/articles/syty/propshaft.htm

 

[Lynn D. Brown]

Yes - I ordered these sized bolts and got them at O'Reilly's. But they are only 9.8 or 8.9 hardness, I forget which. I wonder if that matters ? I am also wondering if the bolt heads will be too big. I wonder if anyone can get these bolts w smaller heads ?

 

[Fred Aldrich]

10.9 is similar to Grade 8
9.8 is similar to Grade 5
8.9 is similar to Grade 2

10.9 bolts are absolutely necessary.

 

[phil conrad]

if you have trouble finding them locally let me know. I can get all 8 for $15.00 including shipping in the lower 48 states.

 

[Lynn D. Brown]

Propshaft bolts

Propshaft bolts

Phil,

I just found the 10.9 Gr. bolts at a local Bolt & Nut place. The hex heads are awfully big, however, so I'm wondering if they will fit in. This is probably why GM went w the male Torx heads. But they are really marginal. I almost stripped 2 or 3 of them getting them off.