Hi,
I'm experiencing a less than ideal brakes bite on my C4S. Rotors are approx 2000 miles old, same as the pads (both those items show normal visible wear) and system flush.
Initial bite feels spongy and to me I have quite long braking distances overall.
Car is fairly new to me, so maybe that's all the brakes have to offer and I'm expecting more?
Hate to do this as comparison, but my Toyota Tundra seems to have sharper brakes.
Thoughts?

 

Honestly I experience the same (C2). I currently change rotors and pads on the rear axle (ATE-bundle) and check result when streets are salt free. If I am not happy with it I think about swapping the pads on both axles to Ferodo DS 2500 pads. They yield a higher friction-coefficient, although the current one would have to be known in order to assess it of course. So trial and error

 

Interesting. OK, bummer.. it seems like they are overall a bit inferior to other similar sports cars I've had in the past (Boxter, S2000, GTI). I might play with different pads as well, see if I can improve things.

 

C2S and all I can say is rock hard pedal very easy to modulate... I cant forget running around 210kph when a fu..in truck swerves to the overtaking lane... slam on the brakes and the car slowed down so strong the mrs and I felt dizzy after... truck bed was a few meters away from front hood!!! Great brakes... OEM's! Just my experience... still that way after replacing once everything rotors and pads... OEM's!

 

Then something is not right with mine, as this thing is not slowing down quickly enough

 

I agree. I had replaced the brakes with non OEM on my Boxster and the brakes were not as good. Went back to OEM pads and rotors and it was good again. Have OEM on my 997C2S and brakes feel great. No mushiness on the pedal.

 

90% of braking has to do with pad composition. Start by trying some different pads.

 

I have to think it's a malfunction in the system- brake master cylinder, caliper piston hang-up, etc. There may be a good-better-best pad choice, but a spongy pedal and long braking distance wouldn't be solely up to pads unless they're some $10 pad/rotor combo from a disreputable auto service chain.

You say the car is fairly new to you, do you have info on service history? Like anything about what brake fluid is in it? Have you looked at the reservoir? Fluid should not be a dark color.

I hope you have an indy shop, but even a dealer could get to the bottom of this, it could possibly be as simple as not having the brakes bled properly.
It's not remotely normal.

 

Stock rotors, stock pads, recent brake fluid flush? The OEM stuff is fantastic on the street so something is wrong here.

 

S Porsche brakes are extremely capable. If yours aren't confidence inspiring or spongy, someone has installed inferior components or did not properly bleed the system.

What rotors and pads were installed 2,000 miles ago, was the brake fluid renewed and properly flushed?

The combo we're running on our non PCCB car is dba (disc brakes Australia) 2-piece slotted front rotors with 1-piece rears and Hawk Ceramic (yellow box) pads with Motul RBF600 fluid (use that in all my cars, even the DDs).


These are the part numbers for S rear brakes and pads. Your front rotors part numbers will be different as this was a replacement set so just the front rotor rings as we already had the hats from the prior set. Get the OEM pad dampener set from Suncoast too.




It's also possible that you have air in the ABS system. Find a road with some loose dirt on it, like where they're building s house, and do some stops on the dirt where you make the wheels skid and the abs pump kick in. This will bleed the abs system if you don't have a Durametric tool where you can activate the pump manually. After doing that, bleed the calipers again to get that air you evacuated from the pump out of the system
Also, if the brakes didn't go through a correct bedding procedure when they were first installed - Google brake bedding procedure - then you can glaze the pad surface and the brakes won't have good initial bite and will feel like you describe. If that's the case, the pads need to be removed and sanded (wear a mask), the rotors cleaned with red can (not green can) brake cleaner, put back together, and rebedded.

Good luck.

 

Have you bed-in your pads and discs? Having a good pad transfer layer on the disc face helps ensure that the pads in the calipers have something to grab. Pad compound is a great way to improve the initial bite. Our most popular sport compound is the Ferodo DS2500. They're perfect for daily driving, canyon carving, AutoX, and even light track duty in some cases. You can see them (along with our full brake menu) in the link below:

https://www.essexparts.com/my-vehicl...4S/Iron%20disc

Here's a video we did years ago on pad and disc bed-in. This can go a long way towards improving your brake feel.

 

Good video. The only thing I do differently is I make those first few stops with progressive braking to introduce heat into the braking system more gradually with respect to pedal pressure. If you get them so hot in this initial bedding that you have brake fade you can actually glaze the pad surface and they won't recover from that without being removed and resanded down to fresh material.

So I do:

1. a light pressure stop from 40 to 10
2. a light pressure stop from 60-10
3. a medium pressure stop from 60-10
4. a slightly harder pressure stop from 60-10
5. same pressure as 4 but 80-10
6. a final almost full pressure stop from 80-10
7. then a 5 mile drive back home with no stops and I don't set the parking brake until the brakes have fully cooled.

This process has worked very well for me for a couple decades and probably 10-12 pad and rotor changes on multiple cars.

 

2009 C2S 178K miles

Porsche brakes are notoriously fabulous. It is true, however, that experienced track junkies can induce fade, but for most of us, this will never happen. If you are not getting great braking, something is wrong. Porsche brake design is famous for its rigor. From the Porsche website... I found this on the Cayenne web page, but it is the same going back to 2000 when I purchased my first new Porsche:

“The final design of the brake system derives from our fading brake cycle, which is one of the most sophisticated in the whole industry,” explains Alexander Prahst, head of development for ceramic brakes. The extreme test takes place on the high-speed circular track in Nardò, Italy, and consists of twenty brakings. The testers accelerate the car from 55 to 145 mph. Then they hit the brakes. After fifteen brakings, the discs reach temperatures of up to 1,380 degrees Fahrenheit. To test the cooling efficiency, we let the brakes cool down to 300 degrees between the fifteenth and sixteenth brakings. With the last five brakings, we then check whether their frictional coefficient has changed or whether the brakes work with the same cool composure as at the beginning of the test,” says Prahst.

No one does this that I am aware of. After I purchased my 2000 Boxster S new, I received a letter in the mail from Porsche describing the brakes and how they were developed (as noted above).... Porsche has always been proud of its braking systems.

So again, if braking is not great, you have a malfunction (maybe still some air in the lines) or you are not using Porsche-labeled product.

You can do a quick test to see if you are getting enough bite (not overall heat dissipation, but just bite and immediate heat dissipation). Bring the car up to say 70 MPH, and pound them hard and stay on them. Seriously mash on them. You should quickly invoke the ABS system... you will feel it. The nose will drop some and the car will start to "hunt" like a dog's nose on the ground... jostle back and forth. My first track instructor just said "just hang on and guide the car straight". If this does not happen, there is something wrong with your brakes. When I purchase my 2000 Boxster S, I was shocked at how much pounding a car will take... going from 120 MPH, full braking at the end of the straight down to a hard 90 degree right hander..... the brake and the throttle were mostly binary... full on, one or the other. And the car did this for 20-30 minutes and I never experience brake fade while always invoking the ABS.... full bite and no fade ever.

One other thing, once the brakes heat up... they will make a horrible scraping sound, like metal on metal.... no worries, that is what they do when they get hot but I never felt a change in performance even when they were screeching to high heaven.

OK, one more thing.... if you are not getting the stopping distance you are expecting, AND the ABS is kicking in, then the issue is your tires... they are not gripping enough. If the ABS system is NOT kicking in, then you have a braking system malfunction. I am assuming, of course, you are mashing the brake pedal for this test.

OK, even one more thing.... we are always coming back to defining "best" or "better"... some folks put track-oriented systems on their car thinking they are improving their brakes for the street. What exactly were you looking for? As I understand it, the best track-oriented systems don't bite until hot. So.... if you put on track-oriented systems and you are not getting initial bite, you brakes may not be hot enough... or said another way, you messed up your car.

Peace
Bruce in Philly (now Atlanta)

 

Spongy brakes in any car is mostly caused from air in the system due to a poor bleed. I would be starting there as the cheapest place.

 

Also from experience make sure you use OEM brake sensors - Terrible squeal can happen with subpar sensors.