Backbone bolt specifications
Thread Starter
Safety Car
Joined: Apr 1999
Posts: 4,623
Likes: 2
From: Ohio
Backbone bolt specifications
Are these bolts to be torqued at 60 lbs/ft? It seemed to me that they might be more, but I have looked in two manuals, and while it's called something different by GM the description is different then what I think it's called on the bolt torque spec page(s).
Melting Slicks
Joined: May 2000
Posts: 2,148
Likes: 1
From: Chandler AZ
Re: Backbone bolt specifications (h rocks)
It's called a "driveline support beam" and they spec 60 ft-lbs to the differential and 37 ft-lbs to the ZF6. Seems a bit light to me too; but maybe with everything being made of aluminum and magnesium it can't take it.
Did you put in those reinforcement plates from ZR51 Perf? I think Bill specifies more torque with them because they spread the load much better.
Did you put in those reinforcement plates from ZR51 Perf? I think Bill specifies more torque with them because they spread the load much better.
Thread Starter
Safety Car
Joined: Apr 1999
Posts: 4,623
Likes: 2
From: Ohio
Re: Backbone bolt specifications (gcrouse)
George, we made up a set of beam plates for the top and bottom of both the front and rear. I did torque them to 60 lbs/ft based on the factory manual. Do you know what Bill recommends? I can see where you wouldn't want to over torque the front one especially, because it's clamping right over the tail shaft bearing. With the new motor the thing is just brutal, so when I mentioned it to my builder, he jumped all over it. We spent five hours on it yesterday and knocked it out. Didn't use the urethane caulk. Tried the local NAPA that was open, but nothing that was a cross reference to the GM part #. Frankly you could probably use Liquid Nails! Or nothing! We chose the latter.
Melting Slicks
Joined: May 2000
Posts: 2,148
Likes: 1
From: Chandler AZ
Re: Backbone bolt specifications (h rocks)
The goop in between was to help stop the movement between the pieces, which is what you're doing by clamping it better; I didn't put anything on mine either.
I looked up Bill's page, and he gave the same torque numbers for installing his plastes. I followed his instructions to the letter, so I must have been remembering it wrong:
http://www.zfdoc.com/c4beamplate.htm
I looked up Bill's page, and he gave the same torque numbers for installing his plastes. I followed his instructions to the letter, so I must have been remembering it wrong:
http://www.zfdoc.com/c4beamplate.htm
