DanaT

I have searched the forums, and really the "consensus" seems to be "use OEM pads".

Right now my 04 CTT has Textar Ceramic E-pads front and rear. During normal driving it seems to stop OK, but not like I think it should (my F150 seems to have more "bite"). When I get on it (say passing a car and then slowing) it almost seems down right scary and the CTT just doesnt seems to be stopping well. I really noticed this when coming back from skiing and passing a slow moving vehicle. It was above the speed limit (the CCT accelerates pretty well) and a slight down hill grade (maybe 2%). It didnt like coming down from about 80mph to 55mph. That should have been no problem.

I am thinking that the Textar ceramic pads are to blame. The rotors are worn (they will be changed our when it gets warm...dont like doing brakes in freeing weather) and close the limit. The rotors have about 50K miles on them. The pads about 25k. The previous set of brakes were new porsche rotors/porsche pads. It was a few years ago, but they always seemed to stop really well no matter what speed. The textar seem to be "fading". When it is slow loss of braking power, it seems to be harder to notice. It is the frog in the water situation.

I went with the epads because I got tired of on of favorite hobbies: cleaning wheels. They are definitely lower dust.

Pelican is even carrying the e-pads anymore. That may be telling me something.

So my plan is maybe for the next few months just buying a set of pagid OEM pads. Slapping them on. Then in the spring buy a new set of brake (pads/rotors) and do it right.

Has anyone experienced any other reason (except poor pads) that would explain decent braking in "normal" driving but brakes that dont really do much when agressive/high speed? I may just have to take of the hobby of washing wheels morning/noon/night again if OEM pads fix it.

I have read that some have had good luck with Hawk LTS pads.

Does anyone have any recommendations on pads? It seems i may have made a bad choice last time.

Miamirice

DanaT

Did you change out the Hawks?

Bosty

Petza914

When you do a brake job, if reusing the rotors and changing pad compound, you have to do extensive cleaning of the rotors to remove the microscopic layer of the old pad material that's embedded into the rotor and then follow a proper bedding procedure once things are put back together, which is what deposits a new layer of pad material into the rotor..

What provides for high initial bite as the brakes are applied is the pad material from the pad itself actually making contact with the same material that's embedded into the surface of the rotor. If you're going to replace rotors in the Spring anyway, that's the time to change to a different pad material too, but you might be able to fix what you already have on the car just by cleaning your rotors really well on both sides with a drill, a roloc pad kit for the drill, and some brake cleaner (don't over saturate the pad or it will sling brake cleaner around when you start using it). After the cleaning process, you'll need to then rebed the brakes. Bedding in, you want to find a safe place to do a few progressively more aggressive stopping events starting at lower speeds and working your way up to higher speed, but never actually stopping - 30 mph to 10 mph with light pedal pressure, 40 mph to 10 mph with higher pressure, 60 mph to 10 mph with slightly more aggressive pedal pressure then a couple more of those more aggressive yet, and yes, it will smell like brakes when you're done - keep driving the car with 30 seconds to a minute or so between each braking event and when you're all done, drive around before for a few more minutes to allow the brakes to cool and return to a normal temperature. When you park don't set the parking brake this time.around.

The other issue you may have if this wasn't done with the initial installation of the pads, is that the face of the pad may now be glazed, which means a hardened slippery layer has formed on the face of the pad due to needing to use heavy pedal pressure without much braking effectiveness that built up too much heat between the rotors and pads. If you want to try to salvage the pads, you'll need to remove this glazing with a file or aggressive grit of sandpaper until you get down to fresh pad material again - if doing that wear a respirator so you don't inhale dust from the pad material.

I run Hawk HPS pads on my wife's 997 and on my 928 and their LTS pads on my pickup and do not have any issues with initial bite or braking effectiveness on either vehicle. I hear the Hawk Ceramics (yellow box) are lower dust with the same performance so if you are going to change to a different pad, maybe try those. When you look at new rotors in the Spring, unless you have the 380 or 390 mm versions from the Turbo S I'd go to a rotor that's slotted. The slots help to keep the pad material fresher on the face of the pad. On street driven vehicles, I actually like slotted & drilled rotors, as the holes give the gas vapor layer (and moisture layer if in the rain) and easy egress route when you first apply the brakes making them more effective, sooner. I don't like drilled rotors for track use as the heat can build up and develop cracks between the holes.

Miamirice

Marv

I have been using dimpled and slotted rotors on the GT3. The cross-drilled rotors tend to crack quickly, even on the street.

Not sure how cross-drilled would hold up on the Cayenne, but I'd be weary based on my GT3 experiences.

mudman2

Are you sure your rotors are ok ? I used Hawks for years with no problem but once the rotors wore down it was as you described

DanaT

Yes, I need to change the rotors. I would say by feel (based upon the lip) there is 1mm wear on each side.

They rotors have about 50K miles on the them. The rotors were replaced at about 22K miles and now at 75K miles.

This weekend I am going to check the vacuum line near the vacuum pump for cracking. I am wondering if this is my cause. I generally notice the poor braking after accelerating (hard). If there is not enough vacuum (because of a crack) it could be that there just isnt enough residual vacuum. Maybe what feels like poor performance in braking is actually just needing a lot more foot pressure because of lack of vacuum.

Any idea on symptoms if the vacuum line is cracked?

Miamirice

knfeparty

I've been down this road...I installed new rotors with Hawk HPS 5.0s and had terrible bite. Towing was kind of scary. Sometimes you would get some heat in the pads and it would be fine. Sometimes after accelerating it would feel like the brakes weren't there.

I bled and bled and bled. I changed the master cylinder. I had already replaced the vacuum booster pump line (it was broken when I got the car).

I installed EBC Yellowstuff. They are pretty dusty, but they fixed the issue. Now maybe there was an issue where I had glazed the Hawks and they weren't to blame, but regardless, the EBC's did the trick and I would recommend them.

I think that you're always going to find the brake pedal a little tougher after hard acceleration for the reason you mentioned- lack of vacuum. You'd think the car would throw an error if it was too far out of parameter, so I guess it's just a design issue. You could replace the brake booster, or the vacuum booster pump. It hasn't been an issue now that I have some pads with good bite.

It's funny because when I got my car, it had so much bite I was throwing passengers in the floor, but the pads were extremely noisy. I think they were a very aggressive Pagid if I remember.

DanaT

The pedal is not "hard". It is squishy and not enough stopping power.

The brake booster is fine. This weekend checked the vacuum line...no cracks.....

I let the car sit 4 days. The pedal remained as hard with engine off as it was saturday with engine off. Probably means master cylinder is fine and no air lines.

I think it might be the rotors/pads.

Have a new set on some delivery truck somewhere. Maybe they come tomorrow.

I am going with "normal" pagid pads. No more ceramic. I dont like the dust, but i dislike poor brakes much more.

Also something that I have read about ceramic pads...they dont work well in the cold. I read that, but come on, hit the brakes on a Cayenne hard from 60 and there should be heat quite quickly. But it is winter. I tend to like brakes to work when its cold because after a day of skiing in the hills, the car might be cold. And going down a mountain pass is something I like having brakes for..even when it is cold out.

DanaT

Update:

New pads (pagid) and rotors on the front today. Only bedded the brakes, but much better stopping. On dry pavement, I can hear the tires locking (they dont skid but I can hear the the tires chirp a little).

Next up are rear brakes.

I used Sebro Slotted rotors and pagid pads. So far, seems like a nice combo. I would have used ATE slotted, but it seems they are not available any more.

knfeparty

Nice that you posted some updates. Looks like you had a similar story to mine. I likewise had a super-firm pedal with the engine off, especially after the MC replacement.

aftCG

Weird. My '04 came with brand new rotors and pads in all four corners. I blush to think where I bought my car from but let's just say they probably didn't use factory parts. It has fantastic stopping power and great pedal feel. I thought I would be replacing them soon but here it is 20k miles later and it's like throwing out an anchor on a short chain.