Just got finished doing the LS1 brake upgrade and thought others might find the following useful. Difference is night and day between the stock and LS1 brakes. I bought all parts from salvage yard (including another set of G-body spindles and rotors) with the exception of the pads, rotors and bearings/races/seals. If you buy the calipers from a yard, make sure you get the two metric mounting bolts, the brake line bolts, and the little shims that hold the pads in.
I'll probably add a few notes in later, I'm going to build another kit and will have more details to add in. I'll also try to get some pics to go along with the write up.
LS1 Brake Mod, machining the parts
Assuming spindle is off of car and you have the LS1 adapter bracket:
1. Remove hub/rotor from spindle.
2. Remove brake dust shield (you will use two of the three dust shield holes in the spindle for this mod): the hole by the bump stop, and the hole closest to the upper ball joint mount.
a) Hole by bump stop: drill through with letter U drill (.368) (3/8 drill will work) and tap through with 7/16-14 tap.
b) Hole by upper ball joint mount: drill approximately 1 1/8 deep with letter U drill and tap 7/16-14 to the bottom. Check this hole with bolt and adapter bracket to make sure bolt doesn’t bottom out, drill and tap deeper if needed. (I used 7/16 X 1 ¼ long grade 8 bolts)
3. Spindle mod: I used a chop saw to remove the ears but a sawzall or equivalent should do the trick.
a) Ear by bump stop: cut about 1” away from the new mounting hole (ear side of hole). I made the cut parallel to the flat on the bump stop.
b) Ear by the upper ball joint mount: cut about 1” from old caliper mounting hole (ball joint mount side) also cut parallel to flat on bump stop.
Note: neither cut is super critical as long as you don’t cut away your new mounting holes and no other clearance issues are brought up. These locations for cutting will at least get you pointed in the right direction.
c) Clearance for caliper bolts and bracket on spindle: I had access to a mill, but a die grinder or equivalent will work. Lay the adapter bracket on the mounting hole flats of the spindle, there will need to be a little material removal of the spindle to get the bracket to lay flat on the mounting flats. Once you have the bracket flat on the mounting hole flats of the spindle, put the metric bolts that hold the bracket to the caliper through the holes (head of bolt will be on spindle side of bracket pointing out). Next you will need to either cut pockets or completely remove the material on the spindle for the heads of the bolts that hold the bracket to caliper. If the bracket will mount to the spindle with no interference, bolt it to the caliper then bolt on the spindle. I also had to notch the caliper bracket a little to clear the heads of the 7/16 bolts, a little handwork will do for this.
4. Rotor/hub mod:
Access to a lathe or brake lathe will be needed (have heard of some milling the rotor off on a mill). Basically the entire rotor section will be removed, with only the hub section left. The hub should be turned to approximately 5.700” OD. Check the inside diameter of your LS1 rotor for clearance. Be careful not to go much smaller than 5.625” OD, the hub can crack between the stud holes and the outside diameter when new studs are installed. After the hub is machined you need to clean the bearings real good or better, just replace them. I also installed longer studs for the addition of the LS1 rotor, just check and make sure your lug nuts don’t bottom out.
5. Parts should be ready to assemble. I assembled everything on a bench before attempting to install on the car. It’s a little tricky getting the caliper assembly onto the spindle, you will need to slightly pull the rotor out a little to get the bolts through the bracket and into the spindle while also keeping the rotor inside the brake pads. Go ahead and tighten the bolts down at this time. Once everything is put on, I ran the lug nuts on and spun the rotor to check for clearance. If everything looks good, install it on the car.
Installation of LS1 brake assembly on car
1. Remove stock caliper from spindle. Leave brake line attached until new caliper is installed, less of a mess.
2. Remove stock spindle from car. At this point you can perform the machining part of the mod. I went and bought parts from a salvage yard and built the kit before removing my stock set-up.
3. Install new ball joints if needed.
4. Install modified spindle assembly.
5. Remove stock caliper from brake line. I used the stock bolt that came with the LS1 caliper to hook the brake line back up. Attach brake line to new caliper.
6. Bleed brakes
7. Install wheel and rotate to check for clearance issues.
8. Check for leaks and brake function before driving.
I'll probably add a few notes in later, I'm going to build another kit and will have more details to add in. I'll also try to get some pics to go along with the write up.
LS1 Brake Mod, machining the parts
Assuming spindle is off of car and you have the LS1 adapter bracket:
1. Remove hub/rotor from spindle.
2. Remove brake dust shield (you will use two of the three dust shield holes in the spindle for this mod): the hole by the bump stop, and the hole closest to the upper ball joint mount.
a) Hole by bump stop: drill through with letter U drill (.368) (3/8 drill will work) and tap through with 7/16-14 tap.
b) Hole by upper ball joint mount: drill approximately 1 1/8 deep with letter U drill and tap 7/16-14 to the bottom. Check this hole with bolt and adapter bracket to make sure bolt doesn’t bottom out, drill and tap deeper if needed. (I used 7/16 X 1 ¼ long grade 8 bolts)
3. Spindle mod: I used a chop saw to remove the ears but a sawzall or equivalent should do the trick.
a) Ear by bump stop: cut about 1” away from the new mounting hole (ear side of hole). I made the cut parallel to the flat on the bump stop.
b) Ear by the upper ball joint mount: cut about 1” from old caliper mounting hole (ball joint mount side) also cut parallel to flat on bump stop.
Note: neither cut is super critical as long as you don’t cut away your new mounting holes and no other clearance issues are brought up. These locations for cutting will at least get you pointed in the right direction.
c) Clearance for caliper bolts and bracket on spindle: I had access to a mill, but a die grinder or equivalent will work. Lay the adapter bracket on the mounting hole flats of the spindle, there will need to be a little material removal of the spindle to get the bracket to lay flat on the mounting flats. Once you have the bracket flat on the mounting hole flats of the spindle, put the metric bolts that hold the bracket to the caliper through the holes (head of bolt will be on spindle side of bracket pointing out). Next you will need to either cut pockets or completely remove the material on the spindle for the heads of the bolts that hold the bracket to caliper. If the bracket will mount to the spindle with no interference, bolt it to the caliper then bolt on the spindle. I also had to notch the caliper bracket a little to clear the heads of the 7/16 bolts, a little handwork will do for this.
4. Rotor/hub mod:
Access to a lathe or brake lathe will be needed (have heard of some milling the rotor off on a mill). Basically the entire rotor section will be removed, with only the hub section left. The hub should be turned to approximately 5.700” OD. Check the inside diameter of your LS1 rotor for clearance. Be careful not to go much smaller than 5.625” OD, the hub can crack between the stud holes and the outside diameter when new studs are installed. After the hub is machined you need to clean the bearings real good or better, just replace them. I also installed longer studs for the addition of the LS1 rotor, just check and make sure your lug nuts don’t bottom out.
5. Parts should be ready to assemble. I assembled everything on a bench before attempting to install on the car. It’s a little tricky getting the caliper assembly onto the spindle, you will need to slightly pull the rotor out a little to get the bolts through the bracket and into the spindle while also keeping the rotor inside the brake pads. Go ahead and tighten the bolts down at this time. Once everything is put on, I ran the lug nuts on and spun the rotor to check for clearance. If everything looks good, install it on the car.
Installation of LS1 brake assembly on car
1. Remove stock caliper from spindle. Leave brake line attached until new caliper is installed, less of a mess.
2. Remove stock spindle from car. At this point you can perform the machining part of the mod. I went and bought parts from a salvage yard and built the kit before removing my stock set-up.
3. Install new ball joints if needed.
4. Install modified spindle assembly.
5. Remove stock caliper from brake line. I used the stock bolt that came with the LS1 caliper to hook the brake line back up. Attach brake line to new caliper.
6. Bleed brakes
7. Install wheel and rotate to check for clearance issues.
8. Check for leaks and brake function before driving.
