[weslp00]

Guys,

Just done the GM Brembo upgrade on my 2SS ...
All fitted ok with new 2 piece rotors but wasn't sure on the caliper mounting bolt torque spec.
I read on here somewhere that it needs to go 162ft/lb which seems a little crazy but with my crappy torque wrench I got to 160...is this ok ?
I have seen so many specs on this torque figure..does anyone know what is correct please ? I hope I haven't done them up too tight ?

Cheers Guys..

[Alpha1BC]

The spec is a torque+angle spec, not just torque. 162 might be in the ballpark of where it's supposed to be but it will vary from car to car. Actual spec is supposed to be tighten to 150 Nm (111 lb-ft) then tighten an additional 15-30 degrees.

In case you weren't aware, you're also supposed to clean both the bolt and caliper threads with rubbing alcohol or something similar to get rid of the old threadlocker. Then, apply Loctite 272 (or equivalent) to 2/3 the length of the bolt and let dry for about 10 minutes prior to installing the bolts. If you didn't do that part, I'd suggest pulling it back apart to add that in. Wouldn't want to risk those bolts backing out lol

[weslp00]

Originally Posted by Alpha1BC

The spec is a torque+angle spec, not just torque. 162 might be in the ballpark of where it's supposed to be but it will vary from car to car. Actual spec is supposed to be tighten to 150 Nm (111 lb-ft) then tighten an additional 15-30 degrees.

In case you weren't aware, you're also supposed to clean both the bolt and caliper threads with rubbing alcohol or something similar to get rid of the old threadlocker. Then, apply Loctite 272 (or equivalent) to 2/3 the length of the bolt and let dry for about 10 minutes prior to installing the bolts. If you didn't do that part, I'd suggest pulling it back apart to add that in. Wouldn't want to risk those bolts backing out lol

Thanks for that Alpha...I got to about 160ft/lb because trying to get an angle with car high on stands was tricky. So measuring 111 ft/lb and 30 degrees is hell. That why I went with 160 because I have seen this figure on the corvette forums that share the same callipers.
It was a brand new set up .. new callipers and bolts with orange loctite from the factory.
I am more worried that I may have over torqued ? What do you think?

[Alpha1BC]

Gotcha. My method of choice to get the angle after hitting the torque is to put a mark with a paint pen or something on the flange of the bolt and then mark out the acceptable range of motion on whatever I'm bolting to. From there just twist the bolt little by little until you're in the proper range.

Having installed with new bolts and everything to 162 ft lbs should be just fine. 160 should also be close enough assuming your wrench accurately measured it. I didn't think to check the corvette stuff but the bolt part numbers match and everything so it should be good. Only reason the torque+angle spec could be better is if the friction in the threads caused the torque wrench to click instead of the clamping force of the fastener, but that's not really an issue for brand new parts.

As for the torque wrench, I'd highly suggest looking at a torque wrench that has a higher range like this one: https://www.amazon.com/TEKTON-24340-.../dp/B00C5ZL1NS . Click-type torque wrenches are typically a little more accurate when setting a torque that's not at the extremes of the range they're rated for, and it comes in handy for brakes, axle nuts, and even when swapping wheels and tires on these cars because 140 ft-lb that the lug nuts require is pretty high for some of the smaller torque wrenches out there.

[weslp00]

Originally Posted by Alpha1BC

Gotcha. My method of choice to get the angle after hitting the torque is to put a mark with a paint pen or something on the flange of the bolt and then mark out the acceptable range of motion on whatever I'm bolting to. From there just twist the bolt little by little until you're in the proper range.

Having installed with new bolts and everything to 162 ft lbs should be just fine. 160 should also be close enough assuming your wrench accurately measured it. I didn't think to check the corvette stuff but the bolt part numbers match and everything so it should be good. Only reason the torque+angle spec could be better is if the friction in the threads caused the torque wrench to click instead of the clamping force of the fastener, but that's not really an issue for brand new parts.


As for the torque wrench, I'd highly suggest looking at a torque wrench that has a higher range like this one: https://www.amazon.com/TEKTON-24340-.../dp/B00C5ZL1NS . Click-type torque wrenches are typically a little more accurate when setting a torque that's not at the extremes of the range they're rated for, and it comes in handy for brakes, axle nuts, and even when swapping wheels and tires on these cars because 140 ft-lb that the lug nuts require is pretty high for some of the smaller torque wrenches out there.

Cool Alpha 👍
Good info here and as for the torque wrench I went out and bought this bad boy just because of this job and those high torque wheels.
It seems like 3 ft long and working with that under the car was a pita.
Yes the bolts part numbers are the same for C7 GS but I am baffled by the torque differences... have you noticed that the stock SS brembo four pots have a steel threaded insert that takes that bolt and the 6 pots haven’t. That raised my question of over torque and stripping threads. But it didn’t happen. Maybe the TTY bolts take up that extra torque in stretch. Either that or I was lucky and didn’t hit the SNAP torque figure

[Alpha1BC]

Ah, that torque wrench should be just fine then. I bet they reach the same torque, but the torque+angle is a little more robust than only torque for getting the right clamping force from the fastener, especially as the vehicle is used and corrosion sets in. Could be a difference in production facilities or expected use or something that's causing the difference? Or maybe GM switched to a new strategy by the time the Camaro started getting built which was a few years after the C7? Tough to say for sure.

As for the SS brakes, I thought those were just aluminum threads as well? Maybe the way the coating was put on made it look like a steel insert? You shouldn't have any issues stripping anything out at 162 ft-lb or the TA spec. Neither of them should get into yield (i.e. they aren't TTY) so shouldn't a a risk of failing them by taking them in and out a few times.

[olblue75]

Well you can do it this way every flat in 60 degrees so half a flat will be 3” degrees.

[weslp00]

Originally Posted by olblue75

Well you can do it this way every flat in 60 degrees so half a flat will be 3” degrees.

Thanks Olblue..I will bear that in mind👍👍

[weslp00]

Originally Posted by Alpha1BC

Ah, that torque wrench should be just fine then. I bet they reach the same torque, but the torque+angle is a little more robust than only torque for getting the right clamping force from the fastener, especially as the vehicle is used and corrosion sets in. Could be a difference in production facilities or expected use or something that's causing the difference? Or maybe GM switched to a new strategy by the time the Camaro started getting built which was a few years after the C7? Tough to say for sure.

As for the SS brakes, I thought those were just aluminum threads as well? Maybe the way the coating was put on made it look like a steel insert? You shouldn't have any issues stripping anything out at 162 ft-lb or the TA spec. Neither of them should get into yield (i.e. they aren't TTY) so shouldn't a a risk of failing them by taking them in and out a few times.

Yes those Camaro 4 pots deffo have steel inserts..I checked with a magnet.
Then I went on rock auto to look at C7 callipers...wow there are hundreds and even though they feature the same 4 pot for some models they don’t have the inserts....and of course all include corvette tax.
Yep this is a weird one and I am glad I didn’t go over the 160 mark..
So they are NOT torque to yield bolts for these calliper kits?..I must admit I thought the new bolts looked different as they didn’t have a thinner waist above the threads. Also that orange loctite goop made them hard to wind in so must affect the torque somewhat..this is a different ball game to my old 2gen Camaro for sure !