Girodisc upgrade on 991 GTS with Centerlocks
08-12-2017, 10:43 AM
#47
Nordschleife Master
Need lots of pics or vid 
08-12-2017, 03:15 PM
#48
Instructor
Thread Starter
08-12-2017, 04:52 PM
#49
Race Director
Subscribing.....on my 997GTS I had installed a GT3 stock brake system...swapped pads from track to street.
Just got. 2017 991 GTS and going back to the track. I've bought from Clark at Apex before and will be on a sales trip,in a week and stopping buy for new helmet and looking into these GiroDisc rotors.
I have 5 lug this time...thank god!....lol....but it seems like the brake pads are bolted to the calipers and I need a special socket to remove pads?
I understand the track pads I need:
Ferodo or Pagid GT3 991 size for fronts?
Padgig GTS size for rear????
So question is the rear goes from stock 330mm to Giro Disc 350mm...so how does the stock pad cover the extra 20mm rotor size?
For street use I need:
Stock front GT3 991 pad?
Rear I can use the stock pads I already have???
Tarett 95mm caliper studs front and rear?
Thanks
Just got. 2017 991 GTS and going back to the track. I've bought from Clark at Apex before and will be on a sales trip,in a week and stopping buy for new helmet and looking into these GiroDisc rotors.
I have 5 lug this time...thank god!....lol....but it seems like the brake pads are bolted to the calipers and I need a special socket to remove pads?
I understand the track pads I need:
Ferodo or Pagid GT3 991 size for fronts?
Padgig GTS size for rear????
So question is the rear goes from stock 330mm to Giro Disc 350mm...so how does the stock pad cover the extra 20mm rotor size?
For street use I need:
Stock front GT3 991 pad?
Rear I can use the stock pads I already have???
Tarett 95mm caliper studs front and rear?
Thanks
08-12-2017, 05:34 PM
#50
Banned
Originally Posted by Jbgill6535
Nice. How has the install been so far?
First rotor took a while just to understand the caliper, brake pad replacement, brake sensor and brake fluid system as I've never done this type of maintenance on any vehicle before. Happy to answer any specific questions from the forum.
This was a helpful video on Rotor brake pad changes.
This was extremely helpful for the oil change.
https://rennlist.com/forums/991/9780...il-change.html
I will be viewing this before flushing brake fluid with SRF.
08-12-2017, 05:45 PM
#51
Banned
Originally Posted by mdrums
Subscribing.....on my 997GTS I had installed a GT3 stock brake system...swapped pads from track to street.
Just got. 2017 991 GTS and going back to the track. I've bought from Clark at Apex before and will be on a sales trip,in a week and stopping buy for new helmet and looking into these GiroDisc rotors. this is for a 2015-16 GTS
I have 5 lug this time...thank god!....lol....but it seems like the brake pads are bolted to the calipers and I need a special socket to remove pads? correct
I understand the track pads I need:
Ferodo or Pagid GT3 991 size for fronts?
Padgig GTS size for rear???? clark is your best source but I did use GT3 stock for front and 991 S stock for rear. I'm heading to werks reunion and don't have a track day on the books so I did not install my Pagids.
So question is the rear goes from stock 330mm to Giro Disc 350mm...so how does the stock pad cover the extra 20mm rotor size? it doesn't. The rear caliper is the limiting factor on the rear rotor. But it's a very small area that it doesn't cover on the inside ring.
For street use I need:
Stock front GT3 991 pad? that would work
Rear I can use the stock pads I already have???
yes but it's recommended to use new pads w new rotors.
Tarett 95mm caliper studs front and rear? yes I believe they are 95mm
Thanks
Just got. 2017 991 GTS and going back to the track. I've bought from Clark at Apex before and will be on a sales trip,in a week and stopping buy for new helmet and looking into these GiroDisc rotors. this is for a 2015-16 GTS
I have 5 lug this time...thank god!....lol....but it seems like the brake pads are bolted to the calipers and I need a special socket to remove pads? correct
I understand the track pads I need:
Ferodo or Pagid GT3 991 size for fronts?
Padgig GTS size for rear???? clark is your best source but I did use GT3 stock for front and 991 S stock for rear. I'm heading to werks reunion and don't have a track day on the books so I did not install my Pagids.
So question is the rear goes from stock 330mm to Giro Disc 350mm...so how does the stock pad cover the extra 20mm rotor size? it doesn't. The rear caliper is the limiting factor on the rear rotor. But it's a very small area that it doesn't cover on the inside ring.
For street use I need:
Stock front GT3 991 pad? that would work
Rear I can use the stock pads I already have???
yes but it's recommended to use new pads w new rotors.
Tarett 95mm caliper studs front and rear? yes I believe they are 95mm
Thanks
08-12-2017, 06:54 PM
#53
Race Director
Usually I just tighten them with my socket until tight and they were thread locked in with blue lock tight. I got real good at removing them and saving them for future use when changing rotors.
Last edited by mdrums; 08-12-2017 at 07:36 PM.
08-12-2017, 07:50 PM
#54
Rear Rotors
When the rear stock rotors (330mm) are upgrade to the GiroDisc 350mm the kit comes with a set of 12mm caliper spacers and longer bolts. Each rotor is specifically identified for the correct corner. Standard size rear brake pads are installed and the void created by the larger rotors is inconsequential.
08-12-2017, 08:24 PM
#55
Banned
Originally Posted by mdrums
I had center locks on my 997GTS.....these drive pins are really only there basically for alignment to the wheel. There is a small amount if any of wheel torque put to them..after all they are Aluminum with tiny bolts....the spec is 23ft lbs
Usually I just tighten them with my socket until tight and they were thread locked in with blue lock tight. I got real good at removing them and saving them for future use when changing rotors.
Usually I just tighten them with my socket until tight and they were thread locked in with blue lock tight. I got real good at removing them and saving them for future use when changing rotors.
The tarret bolt instructions were to tighten the bolt into the aluminum hub to only 5lbs to let the screw compound cure without aluminum threads being stripped. They were very clear that aluminum threads are not strong and can easily strip.
08-12-2017, 09:50 PM
#56
Race Director
Tried 23 and it felt too tight for aluminum threads. Did the 997 have aluminum internal receiving threads?
The tarret bolt instructions were to tighten the bolt into the aluminum hub to only 5lbs to let the screw compound cure without aluminum threads being stripped. They were very clear that aluminum threads are not strong and can easily strip.
The tarret bolt instructions were to tighten the bolt into the aluminum hub to only 5lbs to let the screw compound cure without aluminum threads being stripped. They were very clear that aluminum threads are not strong and can easily strip.
Honestly I usually didn't torque these...just tightened them with a little blue locktite. I reused drive pins for about 2-3 rotor changes...if I could get them off with out issues. Some pins came off some just wouldn't. I had a large stock of new to used pins to choose from.
What a PITA...drums not miss CL's at all...lol
08-13-2017, 12:50 PM
#57
Race Director
When the rear stock rotors (330mm) are upgrade to the GiroDisc 350mm the kit comes with a set of 12mm caliper spacers and longer bolts. Each rotor is specifically identified for the correct corner. Standard size rear brake pads are installed and the void created by the larger rotors is inconsequential.
08-13-2017, 03:46 PM
#59
Race Director
NA430GTS...that's great....
There is a bolt top and bottom of caliper facing you...multi rib torx type of bolt. Suncoast sells a socket,for this and says you need it to remove the brake pads. I've seen others remove pads with out this but how are the pads actually bolted to the caliper but yet still move towards the rotor?
With 20" wheels there so much more room for bigger brakes. I'm thinking maybe the 380mm Turbo rotors and calipers might retro fit right on since the same uprights are shared unlike the GT3 cars.
There is a bolt top and bottom of caliper facing you...multi rib torx type of bolt. Suncoast sells a socket,for this and says you need it to remove the brake pads. I've seen others remove pads with out this but how are the pads actually bolted to the caliper but yet still move towards the rotor?
With 20" wheels there so much more room for bigger brakes. I'm thinking maybe the 380mm Turbo rotors and calipers might retro fit right on since the same uprights are shared unlike the GT3 cars.
08-13-2017, 04:53 PM
#60
Banned
No tools needed to remove brake pads in my experience yesterday. See pic. There is a metal spring that gives resistance then the brake pad connects to the two circular hubs and goes in. White arrows point to where the springs are on each end of caliper. I needed to use a wire cutter to cut the brake pad sensor wires that are routed thru the middle spring in the pic.
BUT you will probably need to bleed the calipers to push the pistons back into the housing. I needed to do this on 3 of the 4 calipers. I grabbed the caliper pistons with my hands and a paper towel and squeezed them to push the brake fluid out into the bleeder bottle.
Worn brakes and rotors are thinner than new so I couldn't get the new brakes around the new rotors without bleeding them. Good video here on bleeding.
BUT you will probably need to bleed the calipers to push the pistons back into the housing. I needed to do this on 3 of the 4 calipers. I grabbed the caliper pistons with my hands and a paper towel and squeezed them to push the brake fluid out into the bleeder bottle.
Worn brakes and rotors are thinner than new so I couldn't get the new brakes around the new rotors without bleeding them. Good video here on bleeding.