So I have the AIM, the 1969 Chassis Service Manual, and I think just about every meaningful reference guide I am aware of...and do not see bolt torque specs anywhere. I am mechanically experienced enough to work without them..but would be nice to have. Do they exist and if so where? I am talking about overall, in general, complete car...ideally.
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late Oct 1969 L46 350/350, M21 4spd, 3.70 posi convertible --As with life, restoration is a journey, not a destination. Though restored cars provide both journeys AND destinations! -
Re: Source for Bolt Torque Specs
Keith-------
Bolt torque specs are in both the AIM and Service Manual. In the AIM they are on each page which shows fasteners. Next to the fastener there will be a number in a "triangle". That symbol will be shown in a list somewhere on the same page. Next to the numbered symbol will be the torque spec.
In the Service Manual there are tables at the end of each section and at the rear of the manual.
The only torque spec I have never found in either the AIM or Service Manual is the spec for the steering arm-to-spindle bolts/nuts.In Appreciation of John Hinckley -
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late Oct 1969 L46 350/350, M21 4spd, 3.70 posi convertible --As with life, restoration is a journey, not a destination. Though restored cars provide both journeys AND destinations!Comment
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Re: Source for Bolt Torque Specs
Joe,
That's because, as you've found, they're not listed. See quote from John Hinckley (may he rest in peace). Being as these are 7/16" Grade 8 bolts (on C@s) I have always torqued them to 80 lb-t. C3 went to a 1/2" bolt and, therefore, the torque would be 100-120 lb-ft.
"There's nothing anywhere in the A.I.M. on the steering arm bolts - they were received at St. Louis as a part of the front knuckle assembly from Chevrolet-Warren. Standard torques for Grade 8 bolts are 45-50 ft-lbs. for 3/8" bolts, 67-80 ft-lbs. for 7/16" bolts, and 100-120 ft-lbs. for 1/2" bolts. The first number is for coarse threads (3/8"-16, 7/16"-14, and 1/2"-12, and the second number is for fine threads (3/8"-24, 7/16"-20, and 1/2"-20.
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Last edited by Leif A.; December 13, 2022, 08:04 PM.Leif
'67 Coupe L79, M21, C60, N14, N40, J50, A31, U69, A01, QB1
Top Flight 2017 Lone Star RegionalComment
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Re: Source for Bolt Torque Specs
Leif------Joe,
That's because, as you've found, they're not listed. See quote from John Hinckley (may he rest in peace). Being as these are 7/16" Grade 8 bolts I have always torqued them to 80 lb ft
"There's nothing anywhere in the A.I.M. on the steering arm bolts - they were received at St. Louis as a part of the front knuckle assembly from Chevrolet-Warren. Standard torques for Grade 8 bolts are 45-50 ft-lbs. for 3/8" bolts, 67-80 ft-lbs. for 7/16" bolts, and 100-120 ft-lbs. for 1/2" bolts. The first number is for coarse threads (3/8"-16, 7/16"-14, and 1/2"-12, and the second number is for fine threads (3/8"-24, 7/16"-20, and 1/2"-20."
1963-67 used 7/16-20 bolts for the steering arms. 1968-82 used 1/2-20 bolts. I use 100 ft/lbs for the latter.In Appreciation of John HinckleyComment
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Last edited by Leif A.; December 13, 2022, 08:02 PM.Leif
'67 Coupe L79, M21, C60, N14, N40, J50, A31, U69, A01, QB1
Top Flight 2017 Lone Star RegionalComment
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Re: Source for Bolt Torque Specs
All SAE grade bolts are designed to provide a specific clamping force range, and this is achieved with a "standard" torque based on the bolt shank diameter and thread type, coarse or fine. For example I recall a 3/8-16 Grade 5 standard torque is around 25 lb-ft.
You can find standard torque charts on the Web, so if you can't find a torque spec in the various GM publications use the standard bolt torque as a guideline. Plain head bolts are SAE grade 3, three radial lines on the head are the common Grade 5, and six lines are Grade 8 high strength bolts that are typically used for suspension components.
The only hitch is that GM has their own standards like "300M". Most approximate SAE grades. I don't have a conversion chart but Joe Lucia might have one.
DukeComment
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Re: Source for Bolt Torque Specs
I might also add pay attention to whether its Lb/in or Lb/ft.
I just finished swapping out my front coils and the lower front shock bolts said something like 80-120 Lb/in and in my haste, I was adjusting my torque wrench to 90 lb/ft all the while thinking damn, these bolts get torqued down a ton!1971 coupe LS5 454/365hp
1969 coupe L71 427/435hp
1969 coupe L89 427/435hpComment
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Re: Source for Bolt Torque Specs
And as Leif correctly states, the units of torque are ft-lbs or in-lbs, or lbs-ft, or lbs-in, and not lbs/ft, nor lbs/in.
GaryComment
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Re: Source for Bolt Torque Specs
Keith,
Give me a call at the following number and I'll send you a torque spec sheet that will help you. My reach number is: (203) 530-0510.
- Ron"SOLID LIFTERS MATTER"Comment
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