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The 330mm to 350mm stock caliper big brake kits are becoming more and more popular. This is a basic walk through on the process of removing your old stock 330mm rotors and upgrading and installing your new 350mm rotors along with bolt and spacer kit. These kits are available from a few suppliers and is an upgrade i highly recommend to anyone with a 996 turbo, 996 c4s, 997 c2s, or 997 c4s.
Tools:
Jack or lift
Sock to remove wheels (some guys have special lugs sockets)
10mm allen socks
10mm standard socket
torque wrench
flat screwdriver
phillips screwdriver
wire brush
added tools that help:
impact screw gun
screw gun or die grinder with wire brush
Step 1:
Jack up car and remove wheel
step 2 Front:
Use a flat head screwdriver to pry the ABS wire grommet out of bracket. Then remove the bolt and nut holding the ABS/pad sensor wires and brake line to the upright.
Step 2 Rear:
Use flat head screwdriver to remove ABS wire from bracket on the caliper
Step 3:
Use your 10mm allen socket and driver to remove the 2 bolts mounting the caliper to the upright. after removing boots, safely set the calipers behind the rotor in the suspension. Use a zip tie or wood blocks to support the caliper so the metal brake hard lines do not get bent or damaged.
Step 4:
Using a phillips screwdriver (impact screw gun is very helpful to use if you have one) remove the 2 screws holding the rotor to the hub. after screws are removed, take rotor off and set aside.
Step 5:
Now that you have removed the rotor, it is very important to clean any rust off the hub so the new rotor sits flat on the hub. Use a wire brush (or screw gun/ die grinder with wire brush) to clean the hub surface until all rust is removed.
Step 6:
Unbox your new 350mm rotors. Clean them with brake cleaner and remove any oil or grease on them.
Step 7 (rear only):
Test fit rotor on hub. It may not fit due to the ebrake shoes contacting the rotor. If this is an issue, use a flat head screw driver to turn down the start screw on the brake shoe adjuster. Turn it a few turns at a time and test fit rotor until it slides over the ebrake shoes.
Step 8:
Install rotors. Use the 2 phillips head screw to mount rotor to hub. Very important to screw these in by hand and not use a screw gun do the heads do not become stripped out. Many people replace these screw when changing rotor and is recommended but not mandatory.
Step 9:
Install your calipers with new longer bolts and spacers. you may need to use a C clamp to push the pistons and pads back in all the way to spread wide enough to fit over the new rotor.
Whether you're using plate style or washer style spacers, install the top bolt first. Slide bolt through the caliper and slide spacer up and use bolt to hold in place. Then line up with mounting hole and finger start the bolt. Now install the bottom bolt into calipers. Slide spacer into place and start bolt with your fingers.
Now tighten the bolts as much as possible with your fingers. After they are finger tight, use your 10mm allen head socket and driver to tighten the bolts to a light snuggle. Its a good idea to do this buy tightening each bolt a little at a time.
After bolts are snug, you need to mount your 10mm allen socket on to your torque wrench. OEM torque spec for the caliper bolts is 63ft/lb. personally i torque them to 70ft/lb but 63ft/lb is the proper OEM spec
Step 10 front:
You will not want to reinstall the brake line/ABS wire bracket. Finger start the bolt to the upright. Now slide the sensor mount back over stud, finger start nut. With your 10mm socket and driver, tighten the bolt and nut back up. Then slide the abs wire grommet back into the bracket.
Step 10 rear:
Slide the ABS wire grommet back into bracket mount on caliper.
Step 11:
Reinstall wheel, lower jack and torque lug nuts to spec.
Step 12:
Repeat on other 3 corners
Step 13
Start car. Press the brake pedal a few time until you have good pedal pressure back. Now take the car for a drive and go through a brake pad bedding process. You need to bed the pads to the new rotors and remove and coating on the rotors left
Notes:
During this install, it is also a good time to change pads and fluid. You would do this the same you would any other time by removing old pads, installing new pads, and then bleeding brakes until you have new clean fluid with no air coming out of the calipers.
Edit:
Pictures wont upload through computer for some reason. Posting then add them with my phone.
What advantage does this bigger rotor offer? My guess is heat reduction would be the only benefit as the surface area of the pads haven't changed. Thus stopping power hasn't changed other than that gained by lower rotor heat which would prolong heat fade. So I imagine this "upgrade" is only needed for cars that will see the track. Am I missing something?
Oh, nice write-up!
What advantage does this bigger rotor offer? My guess is heat reduction would be the only benefit as the surface area of the pads haven't changed. Thus stopping power hasn't changed other than that gained by lower rotor heat which would prolong heat fade. So I imagine this "upgrade" is only needed for cars that will see the track. Am I missing something?
Oh, nice write-up!
The increase in rotor size does a few thing. First it increases the leverage the caliper/pads have on the rotor which increases overall braking power. That increased can be maxed though by limits in the friction of the pads and grip of your tires.
Second, the larger rotor both increases thermal mass for heat absorption and dissipation. This greatly reduces brake fade on track because of the increase in cooling.
Third, because the increase in leverage, it greatly decreases pedal travel to produce the same amount the braking as the standard 330 rotor. This gives you better pedal feel as well as a huge increase in braking confidence.
IMO this is a good upgrade for everyone, especially if you need to change replace rotors anyway. This fits under the stock 18 inch wheels as well.
Nice writeup! However, pedal feel should be static and remain the same either way. Can't see how rotors affect pedal feel.
it does so because of the increase in leverage. Less pedal travel to produce the same amount of braking. Help get rid of the numb feeling with little braking you have for the first 1/2 of pedal travel on the stock 330 rotors.
it does so because of the increase in leverage. Less pedal travel to produce the same amount of braking. Help get rid of the numb feeling with little braking you have for the first 1/2 of pedal travel on the stock 330 rotors.
Right, but you're increasing the diameter of the rotor, not the thickness right? Those are traveling on 2 diff planes. Pedal travel remains the same.
Right, but you're increasing the diameter of the rotor, not the thickness right? Those are traveling on 2 diff planes. Pedal travel remains the same.
the width is the same yes but you are increasing the diameter 20mm and moving the caliper further away from hub center. This increases the leverage point which increases braking power. Due to this increase in leverage, it takes less braking pressure (calipers piston pressure) to produce the same amount of negative torque (braking power) which equals less pedal travel to produce the same braking power.
If you think larger rotors feel like it increases more leverage try the larger 6 piston calipers with larger pads. wow.
agree that going to the 997tt 6/4 piston caliper upgrade is great, but also much more expensive.
stock calipers, spacers, 350mm rotors, good pads, and good fluid is more braking that 95% of guys have the tire grip to handle. It's the best bang for the buck upgrade available and gives you a huge increase in braking ability and confidence.
I think I was one of the very first OG owners to do the 6 piston calipers. I had special uprights that were modified to accept the GT2/3 calipers these have the zircon pistons not prone to piston deterioration as 997tt version. I think you can pick up rebuilt front 6 pistons for relatively inexpensive pricing these days. Stock rears would work great, Seems like a good idea if your going this length to look for 6 pots for the front. Might as well use the full surface area if your upgrading to 350mm discs.
If you think larger rotors feel like it increases more leverage try the larger 6 piston calipers with larger pads. wow.
The 350 6-piston calipers have the exact same piston area as the 4 pots. As such, they both create identical torque when using same size rotors. Larger pads will not create greater leverage either as the amount of pressure created by the pistons pressing on the pads is the same. The larger pads will have the same amount of pressure acting on them as the smaller pads but that pressure is simply distributed over a larger area at a lower per square inch force. It’s plain and simple physics. The larger pads will however last longer and will absorb slightly more heat which will keep the pedal feeling better longer. Nothing more, nothing else. Providing cooling air to the rotors/calipers is paramount no matter what size brakes you have. People go way too Gaga over large calipers and rotors but unless you are tracking the car all you are doing is adding unsprung mass. Not trying to burst anyone’s bubble but the stock brakes are more than adequate for 99% of Street users. For track use, the upsizing is nice but if you are looking to improve brake feel a larger master cylinder and an engine driven vacuum pump and greater brake cooling will provide a much greater and noticeable benefit.. No, I did not stay at a Holiday Inn last night, but I have tried just about every conceivable permutation of brakes on these cars...
12-20-2017, 09:23 AM
DIY 330mm to 350mm rotor upgrade install
