orthojoe

Hey guys,

I took the spyder out today for a quick trip and noticed that the PCCBs are making a scraping sound when I brake. This started after my last track day. I didn't notice the scraping on the way home from the track. The car has been resting in the garage for the past week, and now there's this scraping sound.

The PCCB rotors look ok to me, I don't see any delamination. The rear pads look fine, but the front pads (still a good amount left) look like the front edges are missing small chunks. What should I do?

stevecolletti

You've checked that the pads haven't worn so unevenly that they risk (or have already) touched the rotors?

If the rotors are fine, but the pads have started to chunk, I'd replace them.

Marine Blue

I agree, get the pads replaced ASAP. From what I have been reading the rotors will last a long time but the pads tend to wear quickly and you can only really take advantage of about 50% of the pad thickness before the rivets start showing, causing accelerated wear on the rotors.

BostonDuce

It looks like heat damage to the pads. Look for small cracks between the rotor vent holes.
There is a specification for their allowable length.

Replace the pads with OEM pads only- the rotors are just too expensive to fool with.
There is a "track only" version however.

Do not mention "track" when talking to your dealer.

BD

orthojoe

No cracks in the rotors. I'll take the pads out this weekend and take a look. Thanks guys.

stevecolletti

The track version (P50s) are no longer on Porsche's approved list. I've heard rumors that Porsche is working on devising or buying a compromise pad splitting the difference between stock and P50s.

orthojoe

I got a chance today to pull the pads and take a look:

The pads and rotors seem to look ok to me, I've posted pics below to see what you guys think. one of the pads on the passenger side is starting to show the brass rivets. The chips off of the pad are pretty small and are on the edges of the pads. I cleaned everything off with some brake cleaner and reassembled everything. The scraping noise is gone now. New pads have already been ordered/shipped. Install them now, or wait until I wear the pads some more?

Driver's side:





Passenger side:

khooni

looks like just a small chip. I wonder what is causing the sound if only a small chip?

Marine Blue

One of those pads looks like it has a crack down the middle, not sure if that is "normal" or acceptable. Joe are you going to try to warranty these?

orthojoe

Afshin,

To me, these pads don't look any worse than the track pads I use on my Evo. They seem to be operating just fine now, plus I seriously doubt any warranty for brake pads would be considered on a car that is tracked. I have a new set of PCCB pads en route (btw, Irsinghausen sells their pads at an even lower price than Suncoast) that I will probably install for the next track day. For now I think these pads are just fine for the street.

As far as what caused the scraping sound? I'm not sure... maybe small bits of the pad that flaked off were rubbing between the pad and rotor? After I cleaned everything off, it sounds fine again...

Macster

With steel brakes both my Boxster and Turbo brakes make some noise after some miles. By noise I mean what I hear is a faint squeal when coming to a stop with light braking. The noise is not very bad at all, not like a old truck with brake squeal that makes fingernails on the blackboard sound like a symphony.

What I have found eliminates the noise is to 'wash' the brake hardware. And I suspect this will help you with the noise your car's PCCBs generate.

By 'wash' I mean at a DIY car wash -- I do not have any place where I live to wash my cars -- use the soap/detergent setting of the wand control to spray soapy water on the brakes/wheels. Do not jam the wash wand tip in too close to the brake calipers/pads.

After hitting all 4 wheels make another lap around the car with the wand control/setting on rinse.

Thoroughly rinse the brakes/wheels to remove any soap.

Then make a 3rd pass using the spotless rinse setting. Where I wash my cars when the spotless rinse setting is selected the pressure is reduced and I get the tip of the wand closer the pad/rotor area.

If you want to be extra thorough, move the car forward some to expose areas of the rotors there were hidden/protected by the calipers/pads.

Also, if there are any holes in the rotors be sure they are all clear of any dust build up. I've seen steel rotors with holes and the dust/rust collects in the holes to the point some holes are nearly full. Under hot/heavy braking this can result in the brakes running hotter than they would otherwise.

The idea of the above is to remove the build up of brake dust that gets on the brake hardware, but also upon the dust boots that protect the pistons from the dust.

This dust collects -- among other places -- on the dust boots/rubbers of the pistons which weighs down and interferes with the piston's natural (intended) slight retraction (arising from the piston seal hysteresis) that tends to retrat the piston just a small distance but which allows the pads to pull back away from the rotors.

After doing to the above, the noise goes away and stays away sometimes for months and thousands of miles. I do not track my cars but sometimes subject them to some spirited driving on some nearby mountain roads and almost always after this the brake noise appears and a brake washing clears it right up.

Be sure you drive the car enough after the brake wash to thoroughly dry the brake hardware.

Sincerely,

Macster.

orthojoe

^ Thanks macster. I always appreciate input from the forum 'pro'

The noise that the brakes 'were' making is not the usual brake, high pitched squeal. I know what that is, and how to fix that. This noise was different. The noise was the sound of metal scraping on metal. A dull, low pitch, low volume, scraping sound. You could hear the sound from the start of braking, until full stop. Any insight on what that may have been?

Macster

Forum pro I don't know about that. Just trying to be of some help.

First when the noise can't be attributed to the pads dragging the brakes must be thoroughly examined for possible hardware (pad material/rotor material) breakdown, failure or damage from external causes.

Among other things signs of something (a failing pad, or piece of pad, or a piece of rotor, or a rock chip) is caught and causing the noise, and possibly doing irreparable harm to the brake rotors/pads in the meantime.

If a thorough inspection finds nothing amiss then one has to consider removing the pads to inspect their friction surfaces for any signs of what would have been hidden damage, breakdown, or exceptional glazing.

While you are 'there' consider using an appropriate brake cleaner to remove dust build up from the brake hardware.

If nothing is found that can explain the noise one possible cause is the brakes have simply developed a glaze from their usage.

What I have found with steel brakes and I suspect the same is true of PCCBs (based on the reports of some drivers having these brakes go away in short order on the track) is harder/later braking -- within the confines of safe/sane driving -- results in longer brake life and brakes that manifest fewer problems as they wear.

So, what you might consider is a PCCB (re) brake bed in and try to adapt a harder/later braking technique.

But before you do that, if you can wait...

Total 911 offers a DVD of its first 50 issues. The last 3 issues include a very comprehensive article (3 parts) on PCCBs past, present and future. For anyone with a car equipped with PCCBs or thinking of buying a car equipped with PCCBs, I highly recommend the articles.

So, before you rush out to bed in the brakes you might want to get this DVD and read the articles on PCCBs.

But check the brakes over thoroughly, regardless. With safety equipment I do not like to cut corners.

I might add that one trick we used in the machine shop to check if a grinding wheel was cracked/damaged in some way before installing it on a grinding machine -- and some of these wheels (for center grinders/crank grinders even large surface grinders) were 'huge', up to 3 feet in diameter and sometimes several inches thick... if one came apart while spinning at several thousand rpms... oh my...) -- was to hold the wheel/suspend the wheel by its center hole and tap the wheel's side near its outer diameter with the end of a wooden hammer handle and listen to the wheel. The wheel wanted to ring. A duller sound indicated a cracked wheel which was discarded.

With the pads off you might consider experimenting and seeing if you can come up with a similar technique that allows you to 'ring' test the pads to find a pad that may have some separation of the friction material from the pad backing plate, or deep/or hidden cracks.

Be careful of course. You don't want to break the pad testing it.

You have 8 pads so chances are most (maybe all) will be ok so you can use the sounds of the majority (assuming they are not all bad which is unlikely) to isolate the bad one, if of course there is a 'bad' one.

Sincerely,

Macster.

orthojoe

Macster, thanks again for the help and information. I think the source of my noise was a piece of pad caught. Reason being, after I took everything out and cleaned with brake cleaner, the noise went away.

One question I do have though: How can you tell if a pad has glazed? Do they have a typical appearance?

Macster

It is mostly a matter of experience of being able to spot at least with steel brakes. I've not seen that many PCCBs but all I've seen appeared to be in good shape. (The articles I mentioned in Total 911 IIRC have pics of PCCBs in various stages of poor condition but I do not recall if any showed any with any glaze.)

In extreme cases the pad surface (or even the rotor surface) will have a very slick/shiny and bright surface (and in some cases with a blue/black shade to it from the heat which helped create the glaze condition) compared to the other items, unless all items are equally glazed.

Another check is to run a fingernail over the pad and rotor surfaces.

Unless they all are glazed you'll be able to feel the ones that are glazed by the fingernail test. If they all feel the same the chances are very high none are glazed.

Run your fingernail across the pad from top to bottom or from the outer diameter of the rotor to the inner diameter. The fingernail will likely encounter grooves (shallow most likely) which is normal.

Then if you go the other way, from the front to rear edge of the pad or around the rotor like you are tracing a groove on a record album (recorded music album...) you will be going with the groove but if the feel is too slick, if the fingernail doesn't encounter the same amount of surface roughness as it does when run across other pads/rotors, that's the glazed pad or rotor surface.

The few times I suspected glaze I just roughed up the pad's surface some with a very coarse grit paper designed for use with non-ferrous materials.

In a few cases -- at least one case was a flywheel of a car I had bought -- I used a air powered die grinder with a coarse sanding disc on a rubber pad to effect a slight roughing up of the glazed or near glazed surface.

In some cases with the pads I'd use a file to file shallow grooves at a 45 degree angle on either side of vertical.

But in all cases the brakes were iron rotors and of course the pads were of a material suitable for use with iron rotors.

Now, even though it appears in one or two pics you posted there's a bit of glaze sign, before I did anything I'd just thoroughly clean the brake hardware to among other things remove any oil even that from your touching the brakes, then reinstall the brake hardware and resume driving the car.

Only if further braking problems appeared or if braking performance was down, would I think about doing anything about any glaze and only if it was clear glaze was at fault.

If you want a second opinion, and I recommend it and from a professional tech experienced with these cars and of course PCCBs,take the car round a qualified shop and have the senior tech give you his opinion of the condition/appearance of the PCCBs. I've seen a number of cars with PCCBs but in every case the PCCBs -- the rotor surfaces mainly -- looked just fjne.

In the case of any car (with PCCBs) I've seen at the various dealer service departments I haven't seen any with the PCCBs showing any signs of any glaze or any other problems. But a tech has seen many many more cars and of course in some cases in with PCCBs problems/complaints so he's in a better position to advise you.

Sincerely,

Macster.