PattiR

I replaced the front coil springs on my 1957 Corvette. While doing this I did not have the grade 8 bolts called for to reattach the lower control arm pivot bar. I put in grade 5. I now will get the grade 8 bolts set at the end of the week from Paragon.
Can anyone tell me the correct torque settings ( I could not find this listed in the service manual) for these bolts. I have to replace the temporary grade 5 bolts that I put in one at a time with the new grade 8 bolts and want them set correctly.

Thanks,

Dennis

Donald #31176

According to the ST-12 manual the lower control arm pivot bolt spec is
100-200 ft lbs.

PattiR

I guess I was not clear. This seems high for the bolts that I am installing as they are only 1/2 x24x1&1/2 in long. It's not the control arm pivot bolt, but the 4 bolts that hold the lower control arm to the pivot which keep the coil spring in place.

Thanks,

Dennis

66jack

Here is a torque sheet for ya..


http://www.stl-vettes.com/65Vette/co...rque_Specs.pdf

JohnZ

The ST-12 doesn't describe them correctly, but I think you're talking about the four bolts that attach the ears on the lower control arm pivot shaft to the bottom of the crossmember; SAE standard torque for 1/2"-13 bolts is 103 ft-lbs., and for 1/2"-20 bolts (fine thread) is 120 ft-lbs. There's no such thing as a 1/2"-24 bolt thread.

Photo below shows the "ears" on the lower control arm pivot shafts - is that what you're asking about?

PattiR

That is exactly the part I am talking about. I don't know that much about torque settings by SAE standards, but can I torque those bolts in that tight(120 ft-lbs) and not break off the ears or crack the bolt? I ordered the grade 8 kit (bolts, washers, nuts) from paragon so I suspect they are right for this application. They are fine thread, I was guessing at the thread count(mistake). I could not find any torque settings in the in the ST-12.
66Jack sent me a C-2 list of torque specs and it looks like this same part & bolts are torqued to only 50 ft-lbs. What do you think?
Thanks,

Dennis

Plasticman

Dennis,

I have a hand written spec in my ST-12 for those bolts, and I think they are actually 7/16-20 bolts (not 1/2").

My spec is 60 ft-lbs. on longer bolts, and 50 ft-lbs. on 2 shorter bolts).

I don't know where this info came from (probably DZAUTO), or?

Note that the "standard" spec for grade 8 7/16-20 bolts is 95 ft-lbs, so if you are using new bolts, that should be safe.

Plasticman

PattiR

Thanks, Getting a lot of good info. Will spend the 4th of July replacing these bolts one at a time. The original bolts that I took out were all the same length. I would expect that my new Paragon kit will all be the same 1.5 length as well.

Want to get the best info for a good job.

Thanks for all of the help from the forum.

Dennis