The main part of the difficulty of this brake swap was the swapping of the spindles to a spindle that would take the brake package. We had the front end geometry pretty dang good with the stock metric spindle but in order to bolt these fabulous Stoptech brakes on, a spindle change was necessary. Because of a tight time frame for install, I told Ron I needed a spindle with the least amount of changes necessary to get the geometry back to or better than I had before, he chose the ATS tall.
Basically the ATS is a 1" drop spindle that is also 1" taller than the G body spindle. To compensate for the 1" drop, Ron had me change my tall lower ball joints for ones 1" shorter.
This was not only super simple, but also put the lower control arms in exactly the same spot as before so I didn't have to adjust ride height after the swap. I'm sure he'll say it was for geometry reasons but whatever.
So the spindle is in, ride height same as it was before, now it was time to work on the steering. The ATS comes with a modular steering arm that is curved as it extends away from the spindle. Instructions say to mount it with the curve pointed toward the center of the car. Ron told me to swap them and mount it with the curve pointed out to increase the ackerman. Ron also sent me a new slug adjustable center link and all new rod ends and curved tie rods to try to optimize the steering geometry. Unfortunately, my crossmember has a nub sticking out to attach the triangulation brace to which was in the way of the new centerlink.
With the steering arms pointed out, that meant the tie rods needed to be about 2" longer...fortunately the bump steer kit I had before was able to extend the tie rods out far enough to reach. Everything clears with no interference anywhere and I was able to dial the bump steer back to close to previous specs very easily.
Where I pause the lift is pretty close to ride height. From ride height to full bump it toes out about 3/16" and from ride height up it toes in just a touch if at all. Check out that camber gain though!!
In the interest of time once again, I called this good enough and moved forward with the rest of brake install. I'll revisit fine tuning the alignment specs when I have more time.
So spindles and steering locked in, time to install the calipers. Pretty straight forward here but couple of things I found interesting.
See that top left piston sticking out? I'm assuming it has a knock back spring behind it because when you push it in, it immediately starts to spring back out again. This made installing the brake pads interesting for sure. I finally figured out that a putty knife is a pretty good tool to use to hold the piston in while sliding the pads in place.
Here is the bridge reinstalled.
One more thing, I had some questions about how much unsprung weight these huge rotors and calipers added...so I weighed the G-body spindle, caliper and rotor.
Then weighed the new Stopech 14" rotor, 6 piston ST60 caliper and ATS Spindle.
Virtually the exact same weight! All the added brake force with no added weight. Woot!!
Front is done except bleeding and greasing, I'm starting on the rear today. Wish me luck with the calipers fitting inside the frame rails. Today will either go pretty smooth, or stop in a hurry based on that.