I have a '14 GT with the perf/pack -- Brembo brakes up front. I'm wondering if anyone makes an aftermarket rear brake assembly upgrade: larger rotors, calipers, and better linings, etc. (A pad upgrade won't do it; I've tried that.)

The problem is in the driving conditions I encounter; the front brakes do fine, but in some extreme conditions the rear brakes can't hold w/o some swing-out. It's not a suspension issue; the rear suspension is well-modified with shocks, springs, sways, bracing, control arms. (Extreme conditions = autocross over mountain roads with unusually steep, long grades.)

Appreciate any information and review-type comments. Thanks!

 

It's not "aftermarket" but the 13-14 GT500 rear brakes are an affordable upgrade.

 

http://www.americanmuscle.com/wilwoo...rear-0512.html
http://www.americanmuscle.com/hawk-t...-0514-red.html
http://www.latemodelrestoration.com/...or-Upgrade-Kit
http://www.latemodelrestoration.com/...rade-Kit-05-14

 

Just out of curiosity what pads do you end up running?

 

I do road courses and for the first 4 track days I used Carbotech XP10s up front with stock rear pads. On long, hard brake zones (120mph+) the tail would swing back and forth during threshold braking. I thought about it long and hard and decided the bias is to blame. The rear is under braked due to a low friction pad. The rear of the car is running into the front so to speak. That makes the fronts less efficient too. I was also noticing pad deposits on the rotors front and back. In the rear I expected it, but the fronts are rated to ~1500F.

Solution:

This season I installed XP8s in the back, and along with the XP10s up front (and SS lines, and GT500 cooling shields up front, and RBF600 fluid) my brake bias is now back to normal, and no more "brake dancing" in the back. Steady braking from any speed in or out of ABS control. No pad deposits anymore either.

I race or fairly flat midwest tracks, but I bet you could fix or improve it with right pad selection. Our cars are heavy. For AutoX/track duty they require serious friction materials.

 

I just picked up a set of the 13-14 GT 500 rotors, and caliber brackets.
I have not had time to put them on yet.
I got them from shelby America, gt500 take offs $200 delivered to my door, they even came with calibers, pads, brake lines, and e brake cables.

 

This, it sounds like OP knows what he is doing but that is why I asked what pads he runs. I was at the track recently, running XP20 fronts and XP10 rears, had very little rear end squirm also under heavy braking.

 

Yeah, I'm puzzled too because autox is typically not over 70mph, and you don't need full race pads. This may be different, not sure. I'm curious about what pads he used too.

 

Have you considered it could be a tire issue? I'm confused by a couple things in your post (not being rude, just need clarification).

1. What do you mean "swing out"? If the rear is grabbing too much, i.e. too much rear bias, it would feel loose. Think of locking up the rear brake on a bike - rear gets very unstable.
- What pads have you tried? Have you had fluid boiling issues resulting in one caliper or both rears getting air or both fronts getting air, leading to some undesired brake bias?
2. What do you mean "autocross over mountain roads"? Are you auto-x'ing the car or driving on backroads?
3. Are you running with stability on or off? Sport mode?

I ask because I track my car hard (run in advanced or instructor groups and run the car on full slicks) and I've only had braking stability issues as a result of not enough tire (only with street tires) to handle the aggressive pads I use. When I run race pads with slicks, braking is super controlled and the car is very stable.

So to my first point, what tire are you running? Perhaps you need stickier tires, not different brake setup.

Finally, to your question, yes there are rear brake upgrades available, anything from brackets to support use of GT500 13.8" rotors to new 4 piston rear brake calipers and floating rotors.

I have a very, very hard time imagining a street driving condition that is "too much" for a set of track oriented brake pads. But I'm sure there are some who push the car that hard on some nice mountain roads. I might not have the ***** to do so though