# GLI/20th rear brake upgrade



## born2perform (Jan 16, 2007)

I upgraded my rear brakes from the normal 1.8t to the GLI/20th ones. I also installed new pads. I'm having a rubbing issue on the left side only. It seems like the outer pad is rubbing against the rotor. I can smell the fading/burning pad after I got out of the car after a short test drive. The rotor is also hot which burned my index finger while touching it. It's not normal for a rear rotor to be that hot. Every bolts is torqued to specification. When jacked up the wheel spins freely but scraped on a certain area of the rotor and then spin freely again.

Any suggestions on why that happened?




*UPDATED* 

Sorry, I know this is late. Just updating in case anyone runs into the same problem. Scroll down to post #7 for update.


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## OddJobb (Nov 6, 2004)

born2perform said:


> I upgraded my rear brakes from the normal 1.8t to the GLI/20th ones. I also installed new pads. I'm having a rubbing issue on the left side only. It seems like the outer pad is rubbing against the rotor. I can smell the fading/burning pad after I got out of the car after a short test drive. The rotor is also hot which burned my index finger while touching it. It's not normal for a rear rotor to be that hot. Every bolts is torqued to specification. When jacked up the wheel spins freely but scraped on a certain area of the rotor and then spin freely again.
> 
> Any suggestions on why that happened?


This sounds like there's run-out with regard to the rotor. Did you clean off the hub and/or lightly sand it to remove any debris/rust before installing the new rotor? The rotor needs to sit flush with the hub so it does not hit the pad when you spin the wheel.


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## KG18t (Aug 9, 2006)

The rear vented rotors warp pretty easily due to the parking brake. Apparently a pretty common problem, I've just dealt with it... by not using the parking brake.


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## IJM (Jul 30, 2001)

KG18t said:


> The rear vented rotors warp pretty easily due to the parking brake. Apparently a pretty common problem, I've just dealt with it... by not using the parking brake.


Can you elaborate? Do the vented rotors commony rub on the pads, causing heat buildup and then pad deposits when the parking brake is applied while hot? Why would normal use of the parking brake result in "warped" rotors?


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## OddJobb (Nov 6, 2004)

I've hear this before. Apparently when a car has rear disc brakes, you add thermal stress to the rear rotors by using the parking brake when the rotors are still hot.


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## IJM (Jul 30, 2001)

OddJobb said:


> I've hear this before. Apparently when a car has rear disc brakes, you add thermal stress to the rear rotors by using the parking brake when the rotors are still hot.


Oh, sure, but isn't this also the case with the solid rotors, especially if the issue is really pad deposts and not truely warped rotors? Don't virtually all car enthusiasts know it's a no-no to apply the parking brake when you have hot rotors?

I ask because I'm strongly considering upgrading my rear brakes from the stock 9.2" solid rotor to the larger vented rotors found on the 337/20th and 225 TT, and didn't want to encounter any issues with the parking brake. This would be done in conjuction with the 986 Boxster calipers and 12.3" rotors up front.


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## born2perform (Jan 16, 2007)

It seems the problem was that the brake lever on the rear caliper would not return fully after engaging the e-brake, hence causing the rotor and pad to rub. Ran across other threads that had this problem. 

http://forums.vwvortex.com/showthre...eleasing-as-it-should&p=74980057#post74980057

As of right now I'm not using my e-brake. This "spring thing" from the other thread didn't solve my rubbing issue so I guess I need new caliper. The spring is not strong enough to return the brake lever all the way back.


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