92tsiawd

So I went to a lapping day this friday for a maiden voyage in my 02 996 C2. The good part is that the engine kept together (I just replaced my rear main seal, IMS seal, clutch, engine mount, serpentine belt and spark plugs) I also swapped out the stock brake line for Agency Power stainless steel brake lines and ATE super blue brake fluid. So first of all, the car has really good power, understeers a lot out of the box and the brakes faded out on me. The understeering part I can understand and will fix with some camber adjustment and eventually a set of coilovers so I can get more negative camber with less roll. The part that fazed me was the brake, I thought 4 wheel brembos with stainless lines and ATE super blue would get me through about 6 laps on my local track, I was wrong, I first got the rear brake pad indicator on the dash (the pads are new). Then the brake pedal got mushy on my, after that it sank lower and lower, eventually to the point where I hit the stop for the brake pedal and the car did not even stop. I am totally fazed, I don't understand why the brakes gave out on me. Anyways, is there a brake booster or something that would fade the brakes and would ruin what I have setup for the track? Anyone have any ideas?

mark kibort

First day in a fast car could lead to riding the brakes too much, but more likely, the pads just were not up to the task.

number9ine

+1 on this, stock brake pads don't last long for those of us who are hard on the stop pedal (ask me how I know . As for understeer: in my limited experience I've found that the equipment most responsible for scrubbing is installed between the steering wheel and driver's seat. I came to this understanding at one of my first DEs when an experienced driver turned some seriously smooth--and therefore quick--laps in the same car I was pushing around corners. I've stayed stock for many events now and will continue to do so until I can make the car dance enough that it needs more to keep up with me.

Once you've bought some good pads, you may consider jumpering your brake wear sensors instead of spending $$ on them after each track day. And as for fade, you're looking at your pads between sessions, right? There's no reason to get down to metal. Buy a set of track-compound pads and toss 'em on when you get there, so you have stock pads to ride home on.

92tsiawd

I'll fess up to hitting the brakes and dragging them on a little bit because I was unfamiliar with the car (I am not an inexperienced driver though, been to the track for many solo 1 events prior). Anyhow, I figured no matter how bad my braking was, it wouldn't lead to the brakes being on the floor and me hitting the stop for the brake pedal and the car not stopping, I believe there is something wrong with it but I have no idea what. I am running a time attack with the car on Sunday, I really hope the brakes restore faith in me after I bleed them out tomorrow.

Bill Gregory

You may be already doing this .... One thing that can be done to reduce fade is to not use your brakes to stop when you park after a track session. Slow down as appropriate, however, for the last few feet, turn your engine off and with it in gear, use the clutch to slow it to a stop. This keeps the pads from resting against the hot rotor.

RonCT

I don't think this has anything to do with your braking style / ability. But everything to do with the failure of something in your system. Porsche OEM pads are fine, especially for a first DE. For you to go 6 laps and have no brakes means something is broken.

I'll give you an indication of how competent oem brakes, pads, and fluids are... When my 07 C2S arrived I wanted to experience it on the track "bone stock". It had new pads, tires, and fluid from the factory, but with a "better" alignment (dealer got me -0.08 degrees at delivery). First day at Lime Rock the car was just fine. Ran 1:04 to 1:06 laps consistently, which means I was using 99% of what the brakes had to offer (am in Black). Point being that OEM is extremely potent and the 996 brakes are pretty similar to 997.

Clearly, you need to have your car checked out. Maybe you got air in the system and that killed your braking power.

GlenL

One dragging caliper will cause this. That brake light could be a hint. Maybe that caliper is stuck or the pads are too thin. You don't want to run them down to the rivets as too much heat is conducted to the fluid. (Ask me how I know) Mine are tossed at between 1/4" and 3/8". Plenty of meat for the street.

LDadrenaline

the combination of the fade and your understeer problem means that you need to change up your driving style. It shows that you are braking too late and trying to hustle the car around the corner with the front end still loaded up with weight. In a rear-engined car you need to brake a little bit earlier, get the car turned and then be hard on the power to drive the car through the corner. Driving like this will not only make faster laptimes but will also reduce your understeer and make your pads last longer.

as for just braking, ATE sucks. Get motul rbf600 or better. Also if you dont have stock air ducts to your brakes you may want to add them. Brake cooling plays a significant effect on fade. Lastly, as others have said, once you start going to the track more you will definitely need a dedicated set of track pads. They are made to operate at a higher temperature than street pads so they last much longer. On the flipside they can't really be run on the street (safely) because they will never hit their operating temperature.

92tsiawd

A stuck caliper actually makes sense. All the pads actually have a lot of meat on them but if one caliper was dragging, it would be conducting heat to the brake system non stop, would make sense that it boiled the fluid beyond anything I've ever felt. I am going to head over to the shop now to try and see if they can fix my problem. Thanks for your suggestion

RonCT: that's exactly what I was thinking, it felt like one time when I was at the track and popped a brake line (yes it was scary, will never cheap out again on stainless lines). Pedal went right to the floor that time, didn't stop the car and the pedal effort didn't come back. Anyhow I'm 100% sure that if there wasn't a problem with my braking system on the car, I wouldn't have any problems with it at the track because I'm sure OE equipment including pads and fluid would be sufficient for a lapping day.

mhm993

Could I suggest the obvious....try flushing the brakes again. Sometimes a bit of air or old fluid isn't cleared out.

Land Jet

Sounds like the brake fluid to me. The newer heavier cars need better than ATE blue. SRF won't let you down.

mglobe

I agree with both of these comments. I'll add that when you flush the brake system, make sure to also bleed the clutch. It shares the same system with the brakes, and I've found some significant air bubbles hiding in the clutch in the past.

JackOlsen

Even a driver with the most rookie style imaginable (which 92tsiawd is not), shouldn't be cooking the brakes in six laps. Although let me ask, what are the braking zones like? If we're talking 5th-2nd-gear turns, you could do it.

If you've got evidence of a sticking caliper, I'd follow that lead first. If you boil the brake fluid in/around one caliper, you're still introducing gas into the system, which is compressible in a way that liquid fluid isn't, and would easily explain your pedal issues.

In the future, if you lose braking like that, pump the pedal as an immediate life-saving technique. Until you get into the pits, compromised brakes are better than none at all.

Porsche brakes are better than most other performance cars, but a 2002 911 is a pretty heavy car. But the top three components that are going to help improve things are: 1) fluid (which you've got -- although did you bleed out all of the old fluid all the way to the calipers?), 2) pads (stock should be okay for six laps on most any track, but there are pads that handle track heat better), 3) driving style (which is an issue with some beginners and even intermediate drivers). Stainless steel brake lines are pretty much irrelevant.

Understeer is built into most performance cars, nowadays. But if your history is with front-engine cars and you're ambitious with corner entry, then a counterintuitive change in driving style will likely improve your lap times and change the way you think about a 911. What kind of car were you tracking previously?

92tsiawd

The track that I went to is pretty progressive without an abrupt end of the straight 5th to 2nd turns, a lot of the turns. My history is with front engined car, my previous car was a Mazda RX-8, I have been to DEs, solo 1 events, time attacks and lappings day a total of 40 to 50 times with that car.

I was paying attention to the brakes and when I was driving by parked cars, I heard some sort of scratching noise coming from the brakes, had my gf stick her head out the window, sure sounds like a sticking caliper. Took out my laser temperature gun later in the day, a quick scoot on the highway and the result were that the passenger side rear brake rotor was 20 degrees farenheit higher than the drivers side. I will be going to the same track tomorrow armed with the temp gun, will post further results. I really hope this is it so I can fix it and be over with, how do you fix a sticking caliper? Rebuild?

GlenL

I'd pull the wheel and check the pads, inner and outer. It could be sticking on the inside you could have no pad left.

A good time to grab a screwdriver and force the pads back, too. Might clean something off. Might not move and then you'll know for sure.