Brake caliper bolt torques correct?
Why does my 1967 GM Service Manual show a torque of 130 lbft for the caliper half retaining bolts and 130 lbft for the caliper to the mounting bracket retaining bolts when the chart for standard torques for different bolt sizes shows a standard torque for a 7/16 grade 8 bolt is 52 lbft for coarse threads and 58 lbft for fine threads. I don't believe you can torque a 7/16 bolt to 130 lbft without failure. What is a good torque value for these applications?
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Re: Brake caliper bolt torques correct?
Gary-------
If that's what it says, it's partially wrong. Here are the correct torque specs:
FRONT caliper housing bolts-----130 ft/lbs
REAR caliper housing bolts--------60 ft/lbs
Caliper mounting bolts (F&R)-----70 ft/lbs
The above specs apply to all 1965-82 Corvettes.In Appreciation of John Hinckley -
Re: Brake caliper bolt torques correct?
Thanks for the information. I've also noticed differences in torque values between the service manual and the assembly instructions.Comment
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Re: Brake caliper bolt torques correct?
Gary------
In general, the torque specs in the assembly manuals are given with a range. The specs in the SERVICE manuals are usually a singular value which is in the middle or near the middle of the range. Actually, anything within the range shown in the AIM is acceptable. However, if you use the SERVICE manual spec or the middle of the AIM torque range for the specific fastener, you should be OK even if your torque wrench is not in perfect calibration.
Of course, torque values for the caliper housing bolts are not given in the AIM since the calipers were supplied to St. Louis as an assembly.In Appreciation of John HinckleyComment
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