Brake Pad bedding / Rotor deposits

[DJbrand1]

I have a 944 Turbo S with the Big Blacks up front. I use the car for DE's. During street duty I have some cheap Metal Masters, before an upcoming DE I switch them out with some Pagid Blacks about 5 days or so beforehand and use them lightly to try and scrub off the Metal Masters coating on the rotors. Getting to the track I'll find some back roads and drag the pads lightly to try to get some heat in them then perform around 6 medium to hard stops from 60/70 to 20 mph. After, I return to the track using the brakes as little as possible to cool them down. With this procedure I am still getting some pretty bad deposits on the rotors and get a lot of vibration. Anything I am doing wrong here? I drove around a week after the track with the Pagids still in to try and scrape the rotors clean but so far no success. Is the last resort to get the rotors cut and try again? Thanks for the help!

[cjbcpa]

I believe the issue may be the different binding compounds used in the pads from different manufacturers.

This compound will normally work its way off of the pad onto the rotor when you bed them in. Bedding in helps to get it evenly "baked" onto the rotor. Introducing a different brand may be causing that brands compound to react badly with the first creating the deposits. I think dragging the brakes is only adding to the problem. I had this same issue when I was forced to change pads at the track and had to go with what was available in the pro shop.

A good workout with a scotchbrite pad can often remove the residue. May be easier to remove the rotor to do a thorough job.

My solution, leave the track pads on all the time if you are driving it on the street only occasionally. Alternatively, try a street pad from Pagid. They probably use the same or similar compounds.

Hopefully someone else will chime in and tell us if I am talking total smack, but I think this is an accurate diagnosis.

 

CB



 

[Larry Herman]

Chris is pretty much correct here.  It is usually an incompatibility of brake materials that can lead to your problem.  If it is not that deep, cleaning it off may work.  You can use something more aggressive than a scotchbrite pad.  Another thing that can occur is crystallization of the rotor metal due to material induced hot spots.  If that happens you usually wind up replacing them.  Cutting the rotor should fix it if it has enough thickness left.

[betegh9]

DJbrand1 wrote:

I have a 944 Turbo S with the Big Blacks up front. I use the car for DE's. During street duty I have some cheap Metal Masters, before an upcoming DE I switch them out with some Pagid Blacks about 5 days or so beforehand and use them lightly to try and scrub off the Metal Masters coating on the rotors. Getting to the track I'll find some back roads and drag the pads lightly to try to get some heat in them then perform around 6 medium to hard stops from 60/70 to 20 mph. After, I return to the track using the brakes as little as possible to cool them down. With this procedure I am still getting some pretty bad deposits on the rotors and get a lot of vibration. Anything I am doing wrong here? I drove around a week after the track with the Pagids still in to try and scrape the rotors clean but so far no success. Is the last resort to get the rotors cut and try again? Thanks for the help!

You Porsche guys sure like to spend $$$ on brake pads. I bought Porterfield R-4 race pads for my car and don't have any problems you describe. I use them on street, track and AX. The front rotors have been on the car since 2003 and they are due for new ones since I wore down the slots. The rear Zimmerman drilled rotors will probably go for another 4 years. I agree that Pagid make great pads of all types, but for DE, the Porterfields are real easy on the rotors (proper driving helps too), very little dust and minimal squeal, and good friction coeficient. These are very similar to Performance Friction pads for less $$$.
Follow the bed-in procedure and GO!