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I've cut 20 year old rubber lines and they were just fine. i'd put big money on the lines not being the issue.
Also, standard 997s don't have ceramic pucks as far as i know.
I'm just seeing it as cheap, yet effective upgrade. Even cheaper then the pads. Maybe it might be "user error" or the track since it has happened before on his previous track car.
"Having had brake heat issues in the past with my previous car on track, I did some research on what brake setups people typically use. I ended up deciding to go with Performance Friction (PFC) 08 compound pads, with the stock rotors and calipers."
I'm just seeing it as cheap, yet effective upgrade. Even cheaper then the pads. Maybe it might be "user error" or the track since it has happened before on his previous track car.
"Having had brake heat issues in the past with my previous car on track, I did some research on what brake setups people typically use. I ended up deciding to go with Performance Friction (PFC) 08 compound pads, with the stock rotors and calipers."
For some background, my previous car was a Ford Focus ST, which is front wheel drive and heavily relies on brake-based torque vectoring, which basically ends up leading to power braking out of every corner. On track with new stock fluid, I overheated my calipers and eventually boiled the fluid, although it wasn't until my second HPDE on a longer track that this happened.
I included that info mainly to explain why I went straight to Motul RBF600 and upgraded pads, as well as having a shop flush the system to avoid me screwing anything up.
For some background, my previous car was a Ford Focus ST, which is front wheel drive and heavily relies on brake-based torque vectoring, which basically ends up leading to power braking out of every corner. On track with new stock fluid, I overheated my calipers and eventually boiled the fluid, although it wasn't until my second HPDE on a longer track that this happened.
I included that info mainly to explain why I went straight to Motul RBF600 and upgraded pads, as well as having a shop flush the system to avoid me screwing anything up.
Are applying the same braking technique on the 997 as you did on the Focus. You target fixated on the Civic and started to run wide so maybe you're still applying old habits w/out realizing it.
I watched the video and the brakes are making the same squeal in all the same places. @4:50, the car was still slowing down pretty well - you didn't even miss the apex by much. There was also plenty of straight and time off the brakes for things to cool sufficiently. Maybe there was something going on, but it isn't readily apparent to me in the video. Putting it all together - based on your description in this thread and commentary in the video - I would say you have a residual air bubble on one side of one caliper, probably a rear. Like I said, you can definitely hear the brake squeal @ 4:50, so most of the system is working. And a small air bubble will cause the pedal to travel a little, but not to the floor. If you boil fluid, you are going to pump like there's not resistance.
In any event, if you have that pedal issue at the track in the future, you could just bleed you calipers (at the track) and push the bubble out. It takes ~15 minutes for all 4 wheels.
I'm pretty sure that's not a pad//rotor issue. PFC's don 't really gas out, and they seldom (if every) glaze as they have a very forgiving bedding process.
My money is on an easy fix when you bleed the calipers. You don't need a system flush. No problem running Motul600. SRF is a waste for DEs.
Lastly, you can't compare a front engine car with smaller brakes with a rear engine 911 with 6-pot fronts. You will out brake virtually every other call and do it all day long.
Brake fade can be pretty exiting! Here's what it looked like in my old 996. One caliper in the front boiled. So I still had 3 corners braking and engine drag. You can make most corners - even coming down from triple digits.
I watched the video and the brakes are making the same squeal in all the same places. @4:50, the car was still slowing down pretty well - you didn't even miss the apex by much. There was also plenty of straight and time off the brakes for things to cool sufficiently. Maybe there was something going on, but it isn't readily apparent to me in the video. Putting it all together - based on your description in this thread and commentary in the video - I would say you have a residual air bubble on one side of one caliper, probably a rear. Like I said, you can definitely hear the brake squeal @ 4:50, so most of the system is working. And a small air bubble will cause the pedal to travel a little, but not to the floor. If you boil fluid, you are going to pump like there's not resistance.
In any event, if you have that pedal issue at the track in the future, you could just bleed you calipers (at the track) and push the bubble out. It takes ~15 minutes for all 4 wheels.
I'm pretty sure that's not a pad//rotor issue. PFC's don 't really gas out, and they seldom (if every) glaze as they have a very forgiving bedding process.
My money is on an easy fix when you bleed the calipers. You don't need a system flush. No problem running Motul600. SRF is a waste for DEs.
Lastly, you can't compare a front engine car with smaller brakes with a rear engine 911 with 6-pot fronts. You will out brake virtually every other call and do it all day long.
Brake fade can be pretty exiting! Here's what it looked like in my old 996. One caliper in the front boiled. So I still had 3 corners braking and engine drag. You can make most corners - even coming down from triple digits.
-td
Wow, yeah that was way worse than what I experienced.. I can only imagine what a blown line would be like!
Thanks for the feedback, and I agree. In retrospect, I should have brought a light jack and some basic equipment to the track just for that purpose.
I took off the PFC pads last night, and there were no signs of overheating around the pistons or pads. The rears looked almost brand new.
As for PSM, correct me if I'm wrong but a light comes on in the dash when it engages, correct? I did trigger it once or twice before I got used to the sensitivity of the chassis -- I was turning in too hard and causing the rear end to swing out.
I know the non-GT 911s have open diffs and potentially could use brake-based torque vectoring, but I believe that would only apply to the rear tires where the power is being put down -- and like I said, no signs of overheating there, or even pad wear.
Right now my main culprits are an air bubble in the system, or bad fluid that was retained in the ABS pump and contaminated the system when I started getting into ABS on track.
The only thing i'm doing differently before my next DE is bleeding 1 or 2 pints of motul through the system myself, and bringing equipment to the track to burp any air out of the system.
Wow, yeah that was way worse than what I experienced.. I can only imagine what a blown line would be like!
Thanks for the feedback, and I agree. In retrospect, I should have brought a light jack and some basic equipment to the track just for that purpose.
I took off the PFC pads last night, and there were no signs of overheating around the pistons or pads. The rears looked almost brand new.
As for PSM, correct me if I'm wrong but a light comes on in the dash when it engages, correct? I did trigger it once or twice before I got used to the sensitivity of the chassis -- I was turning in too hard and causing the rear end to swing out.
I know the non-GT 911s have open diffs and potentially could use brake-based torque vectoring, but I believe that would only apply to the rear tires where the power is being put down -- and like I said, no signs of overheating there, or even pad wear.
Right now my main culprits are an air bubble in the system, or bad fluid that was retained in the ABS pump and contaminated the system when I started getting into ABS on track.
The only thing i'm doing differently before my next DE is bleeding 1 or 2 pints of motul through the system myself, and bringing equipment to the track to burp any air out of the system.
Thanks again for the feedback!
i believe the light comes on when its aggressively cutting power. As an example if i crank the steering wheel and throttle away like im going to do a donut it will flash like crazy and cut power. If im just a bit hot into a corner it doesnt but i wouldnt be shocked if its still individually braking to prevent instability or slip. I cant prove that. I do believe in using stability control on these cars but maybe try itcin sport mode too just to see if any difference
I think it could be you, lol. Not trying to flame, but let me explain, and I’m no expert:
1) You are braking in a straight line
2) You are passing other cars
3) You checked the braking system and haven’t found any problems
4) You’ve had issues with fade in the past with other cars
OK, so I, too, have had boiled braked after passing nearly everyone on the track. Trouble is, you can be fast and really hard on the brakes at the same time if you nail the turns, nail shifting, and are on the gas the right way in a DE.
I‘ve found the line between boiling the brakes and no boil is sometimes quite small. The brakes might be able to absorb maybe a half a megawatt of power each time you slow down. That’s a lot of power and heat that must be shed.
If you go out there and plan to not hit the brakes so hard around some of the turns and instead use the corners to scrub a bit of speed, that might make enough of a difference.
All this assumes you don’t find some problem with your brakes.
Subscribed. I will keep eye on this thread as you get the diagnosis figured out.
However, with your stints being so short when you’re experiencing issues leads me to believe there is a different problem. Going 5-10 laps and boiling fresh brake fluid of any kind that has a dry boiling point of 600 F is very unlikely in this application.
If the RBF had been boiled to this degree there would be proof of it upon visual inspection most likely- mainly vapor/air present in the lines. -Nick
It's been a long winter and I finally got out on track last weekend, wanted to update this thread with the final results.
I had a somewhat uneasy feeling about the "prognosis" with multiple suggestions in the thread, so I decided to pretty much do them all.
Before the first HPDE of the season, I installed Goodridge stainless brake lines. The old rubber lines had no visible flaws, but there was a slightly firmer pedal feel after installing them and bleeding with more RBF600.
I also installed the GT3 brake spoilers in the front, and installed rear brake spoilers for an extra insurance policy.
I also changed my bleed procedure to include triggering the PSM/ABS pump while bleeding each corner, because why not.
The day before the DE, I put another couple pints of RBF600 through it just to be 100% sure that the fluid was good, despite seeing no discoloration or debris in the fluid.
During the last bleed, I was seeing air bubbles coming out of the inner bleed screws on the passenger side calipers, but I'm not sure whether it was due to loosening the bleed screw too much or whether there was actually air in the system. I was using a motive bleeder for all brake procedures, and never experienced any pedal softness before that, so i'm unsure of the cause of those bubbles. If I think about it, it seems that there should be no way to suck air in through the threads on the bleed screw with a pressure bleeder but I suppose with the siphon of draining the fluid, that could cancel out the positive pressure? not sure. Either way, I continued bleeding until no bubbles were present after tightening and loosening the bleed screw again.
At the track (Putnam Park), I had PLENTY of braking power and had no issues with fade or pedal softness. In fact, with the upgraded ducting and low ambient temps, I hardly got the PFC 08s up to temp and they were pretty much squealing all day, except for the couple of corners after the front straight.
So in summary, I appear to have solved my brake issues! It felt incredibly liberating to get a full day at the track with no issues and the car ran smoothly and great all day. What a machine, I may be slightly addicted to steering with my right foot now. Already looking forward to my next track day.
Thanks all for your advice.
Bonus picture
Last edited by cham423; 04-15-2019 at 12:33 PM.
Reason: PASM/PSM
That's great that you've got solid brakes again. Coming from moto racing, SS lines are mandatory for a solid brake setup. If I was in your original situation, I would have ditched those OEM rubber lines immediately.
Glad it seems to have been corrected, but to me what you described sounds like knock back. If it happens again you might check your wheel bearings or it could have been caused by the perfect scenario of braking/cornering and just might be something to be aware of.
Also for fluid, don’t focus on the dry boiling point find a fluid with a high wet boiling point. Everyone thinks SRF is gold and they pay accordingly, the reality is after a bit of use it is no different than something 1/2 the cost. I really like Wilwood fluid, it is inexpensive and has both a high dry and wet boiling point.
09-21-2018, 04:34 PM
