dapopa9

I just recently bought a 2005 CTT. The brakes seem like they don't have much grip. Almost like the pads are slick and don't grab the rotors very well. The pedal feels good and is very firm but seems I have to push it awfully hard and even then I think braking should be better. Also both the front and rear pads have a ton of meat left on them.

Maybe just crummy pads on it? If the pads weren't bed in correctly would that cause this feeling?

By comparison I also have a 2005 V8 Touareg and it stops on a dime compared to my Cayenne. It also has a firm pedal with great modulation. When I the pedal hard you can really feel the pads gripping and it comes to stop very quickly.

CaptJim

You could have one or more stuck calipers? I have seen this on other cars. Maybe its time for you to spend some time on the brakes and at least take some measurements of rotters and pads to check for minimums?

Do you do your own brakes? I am going to do mine in the spring.

dapopa9

Yeah I can do the brakes myself. But the pads I can see without even taking anything off and they are like brand new thickness.....I believe they only have a couple thousand miles on them(according to the previous owner). And I don't think rotor thickness would affect the stopping power..would it? I mean on my track car I can run the rotors down until they crack and they still have the same stopping power the entire time.

Stuck caliper? Like the piston is stuck in the caliper and isn't pushing out when the brakes are applied? What is the best way to test this? Pull the caliper and pads off and then push the brake to see if the piston moves?

Thanks for the help!!

CaptJim

What I was thinking is that you don't know the car, what is someone just put some pads on it to make them look good? The Porsche Parts dealer told me there is no room for cutting rotors. Measuring the thickness may show uneven ware, left to right.

With other cars I have repaired, I know the calipers are bad when I have trouble compressing them, corrosion or leaking. I haven't changed and Porsche brakes yet, I don't know what I may run in to from required tools or tricks for performing the job. Thats why I am on this forum. I didn't search yet, but there may be more information in the forum. I was thinking about getting some rotors and brakes form this site. I like the dimpled and slotted roters, they are painted too. http://brakeperformance.com/index.php

Dennis C

My guess would be improper pads for your application. Some pads require quite a bit of heat to operate properly. Maybe somebody put high-performance pads on the vehicle thinking it would be a good idea. When was the brake fluid last changed?

dapopa9

Pedal pressure is good which generally indicates fluid is fine. However I'm not sure about last time it was changed. Old fluid usually gets a weak spongy pedal feel.

Yeah I will check the receipts the previous owner gave me when I get home in a bit. I know they were ordered from Pelican Parts.

CaptJim

I like them too, purchase for my Mercedes all the time.

TozoM8

The vacuum line to the booster could have a crack or the booster is failing.

RoidDroidVoid

This is quite possible. Usually when you get the rpms up, the braking power will improve due to the increase in vacuum and the build up in the booster, unless the leak is so bad that you have no vacuum. If the brakes feel like they are stopping better after coming from from a higher speed then vacuum leaks or booster is what I'd look at.

As mentioned already, racing pads don't work until they are pretty hot so they are no good on the street and that could be the cause.

Also, don't try to test your caliper by taking it off the rotor and the pads out and pushing the pedal. If your caliper wasn't bad before it might be after that move. With no rotor/pads to stop the piston travel, the piston will hyper extend and you could end up with a piston in your hand and brake fluid all over you. There is also a good chance that if that didn't happen, the piston could come out of the bore and not go back in without basically rebuilding the caliper.

RoidDroidVoid
2004 Porsche Cayenne Turbo

dapopa9

OK thanks great info. I will look for Some info on the booster.

mcbit

My 05 CTT would pretty much out-stop most things on the road. From the symptoms you describe, sounds like a pad problem.