Torque specs for upper control arm on c4 corvette
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Torque specs for upper control arm on c4 corvette
I am looking for the torque specs for an ’87 Z52 Corvette for the front upper control arm bushings. I just installed poly bushing in the uppers and I need to know what the torque is for the large nuts on either end of the control arm. Not the alignment bolts but the nuts that press against the bushings. I have heard several different numbers but can’t find a common one.
Also, if anyone has a torque listing for everything on a c4 that would be great. Just ordered the Helm manual so it everything might be in there but haven't seen it yet.
Thanks!
Also, if anyone has a torque listing for everything on a c4 that would be great. Just ordered the Helm manual so it everything might be in there but haven't seen it yet.
Thanks!
Last edited by Jim5pt7v8; Jul 12, 2006 at 06:51 PM.
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From: The Top of Utah
You pretty much have to go by what your are comfortable with or can get from a trusted front end expert. As per Chevrolet, those bushings are not serviceable. In order to replace them, you have to buy new upper control arm assemblies, with the shaft and bushings installed. You can't even buy aftermarket factory replacements like Moog. The only way to replace those bushings is to do as you, I, and many fellow CFers did and replace them with "performance" bushings. Consequently, there is no factory torque spec for those nuts. I had my bushings pressed in for me. When my jumping up and down on the upper ball joint wouldn't swivel the "A" arm down to where the ball stud would reach the knuckle, I figured they were too tight. Best advice I can offer is to go by feel.
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From: The Top of Utah
Originally Posted by Jim5pt7v8
There has got to be a specification for this torque. Will the Helm manual have this?
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PS. I'd LOVE to know where the "another mechanic looked it up as 63ft lbs.?"
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Originally Posted by CFI-EFI
There does NOT have to be a spec for that torque. It isn't in MY Helms, and the reason is, that since the bushings are (officially) non-serviceable, there is no need to either loosen or tighten that nut.
RACE ON!!!
PS. I'd LOVE to know where the "another mechanic looked it up as 63ft lbs.?"
RACE ON!!!
PS. I'd LOVE to know where the "another mechanic looked it up as 63ft lbs.?"
The other mechanic used Alldata to obtain the value.
They had to be tightened at some point when the car was built so in other words. There has to be a torque spec. It is just a matter of who knows it!!
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Originally Posted by Jim5pt7v8
The other mechanic used Alldata to obtain the value.
They had to be tightened at some point when the car was built so in other words. There has to be a torque spec. It is just a matter of who knows it!!
They had to be tightened at some point when the car was built so in other words. There has to be a torque spec. It is just a matter of who knows it!!
There's not a spec in my '96 Helms manual and the bushings are not serviceable items in the eyes of Chevrolet. Therefore a Service Manual is not going to have the manufacturing information you're looking for.
Generally you tighten until you can feel the arm binding during rotation and then back the nut off until the arm rotates freely. Although not applicable to poly bushings, Global West specified 10lb/ft (yes, ten) for their aluminum/del-a-lum bushings that I have on my car.
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Originally Posted by 96GS#007
Generally you tighten until you can feel the arm binding during rotation and then back the nut off until the arm rotates freely. Although not applicable to poly bushings, Global West specified 10lb/ft (yes, ten) for their aluminum/del-a-lum bushings that I have on my car.
Any more ideas let's hear em!
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From: The Top of Utah
Originally Posted by Jim5pt7v8
The other mechanic used Alldata to obtain the value.
Originally Posted by CentralCoaster
96 ft-lbs is WAY TOO MUCH FOR ALUMINUM NUTS.
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Originally Posted by Jim5pt7v8
Now I have conflicting info again as one post says until you can't move the arm but you state until it moves freely. I would think the control arm should be fairly ridgid in its movement. Let's just hope my guess of 50ftlbs is right....
Any more ideas let's hear em!
Any more ideas let's hear em!
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Originally Posted by 96GS#007
Rubber bushings will not allow rotation of the arms. Poly or other bushings like my Global West bushings will. The other post stated he tightened them until they wouldn't move and then he backed the nut off from there. Btw, the factory uses their equivalent of red Loctite on the threads to keep the nuts from backing off.
Thanks all!
Originally Posted by CFI-EFI
That is freaking' Auto Zone!
But thanks for the insight.
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Originally Posted by Jim5pt7v8
Last I checked Autozone wasn't a mechanic.
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From: Good health is merely the slowest possible rate at which one can die
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Originally Posted by Jim5pt7v8
Only a matter of time before I got hit by the sarcasm. Oh well guess every newbie has to go through it on each forum.
It's only because you seemed to so completely miss CFI-EFI's sarcasm. Feel the love! And welcome aboard.
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
First off, GM doesn't invent the torque specs that are in their manual. SAE or someone else most likely defines these based on thread pitch, bolt size, and material, and GM selects the bolt size that does the clamping they require and the safety factor they want.
Hope this helps:
http://www.engineershandbook.com/Tables/torque3.htm
2024-T4 Aluminum, Dry torque in ft-lbs
1/2"-13.... 313
9/16"-12... 413
5/8"-11.... 715
Not sure what size the control arm bolt is.
Hope this helps:
http://www.engineershandbook.com/Tables/torque3.htm
2024-T4 Aluminum, Dry torque in ft-lbs
1/2"-13.... 313
9/16"-12... 413
5/8"-11.... 715
Not sure what size the control arm bolt is.
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From: Santa Maria CA
Yes, the torque spec for that bolt is not in the manual because GM though of the control arms as a complete unit and not serviceable.
When I did my front bushings, I tightened that nut till the free space between the bushing and bushing washer behind the nut was gone, that would have otherwise created unwanted foward and aft movement, but still not bind the normal travel of the control arm. Basically, till the bushings just began to compress, and where seated flush is when I stopped.
Perhaps contacting the vendor of a front end rebuild kit might know the spec?
When I did my front bushings, I tightened that nut till the free space between the bushing and bushing washer behind the nut was gone, that would have otherwise created unwanted foward and aft movement, but still not bind the normal travel of the control arm. Basically, till the bushings just began to compress, and where seated flush is when I stopped.
Perhaps contacting the vendor of a front end rebuild kit might know the spec?
Last edited by 86PACER; Jul 18, 2006 at 05:50 AM.
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Originally Posted by Corvette Kid
It's only because you seemed to so completely miss CFI-EFI's sarcasm.
SARCASM ---> "Last I checked Autozone wasn't a mechanic"<---SARCASM.
Please shoot me if I own a vette and go to Autozone for mechanical advice. That is what this forum is for!!