Rotor life?
07-22-2012, 04:30 PM
#16
The V8 Porschephile
Rennlist Member
Rennlist Member
I'm surprised that nobody discussed re-facing their rotors. True, that in most cases where rotors are re-faced, vibration results. However, putting new pads on an existing grooved rotor begs for squealing; especially where the lip is created at the top and bottom portions of the rotor where the pad seats.
07-22-2012, 06:16 PM
#17
Regarding re-facing the discs, here is what the Porsche service manual states.
* Only in a few exceptional cases is it adviseable to skim the brake discs (if there is a deep scoring or corrosion of the friction surface)
* Only as new discs may be reworked!
* Only rework the brake discs symetrically, evenly from both sides!
* Only in a few exceptional cases is it adviseable to skim the brake discs (if there is a deep scoring or corrosion of the friction surface)
* Only as new discs may be reworked!
* Only rework the brake discs symetrically, evenly from both sides!
07-23-2012, 04:00 PM
#19
Just call me Pops
Rennlist Member
Rennlist Member
Something is going on with rear rotors for '11 CTTs. They're nowhere to be found in US, Sunset says they're on a month to two months back order and P of R thinks this might be "an upgraded part" issue 
05-15-2014, 01:35 AM
#20
Bringing this thread back to life. My 08 CTT (52K miles) has developed a bad break squeal with low speed braking. The pads have between 5-7 mm left but the dealer is telling me that my rotors are "cupped" and the only way to stop the squeal is with a full brake job (pads, rotors, etc). I believe this is the second pair of pads on the rig. Just purchased this car 3 months ago CPO'd too! This is an $$ job so wanted to get forum input regarding the dealer recommendation.
Thanks!.
Thanks!.
05-15-2014, 02:27 AM
#21
Moderator !x4
The rule of thumb I use it 2 sets of pads per rotor, the dealer however has a rule which conflicts with that, every pad change.
At 52k if the dealer has done all the work should put you on the second set in which case i would just do the pads this time
Mine is a dealer maintained CPO
Before I changed the rotors for a squeak I would try different pads first, I out ceramic after market ones on which are great for dust and a lot quieter that oem
At 52k if the dealer has done all the work should put you on the second set in which case i would just do the pads this time
Mine is a dealer maintained CPO
Before I changed the rotors for a squeak I would try different pads first, I out ceramic after market ones on which are great for dust and a lot quieter that oem
Bringing this thread back to life. My 08 CTT (52K miles) has developed a bad break squeal with low speed braking. The pads have between 5-7 mm left but the dealer is telling me that my rotors are "cupped" and the only way to stop the squeal is with a full brake job (pads, rotors, etc). I believe this is the second pair of pads on the rig. Just purchased this car 3 months ago CPO'd too! This is an $$ job so wanted to get forum input regarding the dealer recommendation.
Thanks!.
Thanks!.
05-15-2014, 12:29 PM
#23
The rule of thumb I use it 2 sets of pads per rotor, the dealer however has a rule which conflicts with that, every pad change.
At 52k if the dealer has done all the work should put you on the second set in which case i would just do the pads this time
Mine is a dealer maintained CPO
Before I changed the rotors for a squeak I would try different pads first, I out ceramic after market ones on which are great for dust and a lot quieter that oem
At 52k if the dealer has done all the work should put you on the second set in which case i would just do the pads this time
Mine is a dealer maintained CPO
Before I changed the rotors for a squeak I would try different pads first, I out ceramic after market ones on which are great for dust and a lot quieter that oem
05-16-2014, 12:21 PM
#24
Rennlist Member
Just went through this thought process myself. Here is the data I accumulated:
1) Tech Specs for all models:
I did a search through Google for: Cayenne technical measurements/Brake wear limits and the top result is a .pdf that was right on the money. I didn't put that data there, I don't have that data to put there... I just found it by doing a search on Google.
2) Digital calipers won't give accurate readings of the discs due to the lip on the rotor and the depth of the rotor. You'll need a purpose made brake rotor micrometer, a rotor measurement tool or an attachment kit for the caliper you already own that turns it into a "good enough" deep welled micrometer. There are lots of tools under $50 for sale online. Do a search on Amazon for "brake rotor micrometer" and at least 10 will come up to give you ideas... though, of course, you don't have to buy there.
3) Measurements indicate that after 46,545 miles on my C tt S I have burned off only .6mm and .4mm on the front and rear rotors, respectively, worst case. That is out of a maximum of 2mm allowed. Most of those 46k miles were highway miles.
1) Tech Specs for all models:
I did a search through Google for: Cayenne technical measurements/Brake wear limits and the top result is a .pdf that was right on the money. I didn't put that data there, I don't have that data to put there... I just found it by doing a search on Google.
2) Digital calipers won't give accurate readings of the discs due to the lip on the rotor and the depth of the rotor. You'll need a purpose made brake rotor micrometer, a rotor measurement tool or an attachment kit for the caliper you already own that turns it into a "good enough" deep welled micrometer. There are lots of tools under $50 for sale online. Do a search on Amazon for "brake rotor micrometer" and at least 10 will come up to give you ideas... though, of course, you don't have to buy there.
3) Measurements indicate that after 46,545 miles on my C tt S I have burned off only .6mm and .4mm on the front and rear rotors, respectively, worst case. That is out of a maximum of 2mm allowed. Most of those 46k miles were highway miles.
