When is it OK to just change the brake pads?

primate · 10-18-2007, 06:58 AM

Hi all,

The warranty of my Boxster S expired a few months ago, and I am planning to service the vehicle myself soon (all dealer-serviced until now). I'm actually pretty excited about it and as I am shopping for all the parts, I was wondering what are the general conditions for rotor / brake pad replacement.

I had the front pads and rotors replaced at the dealer about a year ago, and now it seems like the rear ones are due. I've been told that whenever I replace the brake pads, I should typically replace the rotors as well. I've also heard a camp of people say that it's OK to just replace the pads, as long as the rotors are still thick enough to last the next set of pads, and that I don't brake too aggressively until the pads get a chance to "seat in".

Are there any other of key factors other than rotor thickness (assuming they are not warped) that determines whether the rotors need to be replaced? Comments / words of caution?

Thanks,
- K.

JMatta · 10-18-2007, 08:06 AM

If you do not track the car, they should be fine, other than thickness (which you've already pointed out). How many miles are on the rotors? Be sure to check for hairline cracks, since they are "drilled" (cast). The rears do not work that hard, so they most likely are in fine shape.

primate · 10-18-2007, 09:48 AM

Thanks JMatta. I don't track the car and I will definitely check for hairline cracks.
- K.

Ferrara_racing · 10-18-2007, 01:56 PM

I'd also look for any ridges, it's typical for one to form at the outermost edge. As long as you're there and the thickness of the rotor isn't comprimised, I'd knock off any high spots you find by having the rotors turned. If the surface of the rotor is flat and true then you can just push the caliper pistons back in and change the pads, I might do it on my truck but this winter the Boxster is getting Zimmerman drilled rotors and fresh pads. I figure the labor savings warrants replacement, after all just a turning and pads would run you more at any reliable brake shop.

primate · 10-18-2007, 02:39 PM

Good catch Ferrara_racing. I did notice a raised ridge on the outer-most edge. I guess that means new rotors too then...

Ferrara_racing · 10-18-2007, 03:10 PM

Quote:

Originally Posted by primate

Good catch Ferrara_racing. I did notice a raised ridge on the outer-most edge. I guess that means new rotors too then...

Actually, Porsche has designed the rotors to last more than one set of pads, frankly I like the looks of the drilled rotors and plan on keeping my car a long while so I'm doing the work. There is a spec for how thick the rotors need to be, I don't have my service manual at work but I'm sure you can google it. Anyhow, you may want to just cut the current rotors provided you have the remaining thickness to accomidate the procedure. Or you might be like me and want the look of the Zimmerman drilled, which can be had off Ebay for an entire set @ about 350 from Canada. Depending on where you live you might be able to get them turned for a lot less, good luck...

primate · 10-18-2007, 10:34 PM

Thanks AJF,

I recently got the Bentley Boxster Manual (took them a few months to fulfill the order as they were having problems with the printer that required a reprint) and I'm having a great time going through some of the key sections.

According to that manual the minimum rotor thickness is 22mm (new one is 24mm) for the rear rotors. I agree with you that I will certainly replace them with drilled rotors if they needed replacement. Can't have them not match the beautiful drilled front discs.

I'm going to look into the Zimmerman drilled discs too when I get around to ... thanks for the tip!

Cheers,
- K.

Ferrara_racing · 10-19-2007, 12:05 PM

Zimmerman are the OEM suppliers, if the fronts are drilled then someone already replaced them and left the rears stock, I'd make them all match.

JMatta · 10-19-2007, 02:44 PM

The car in question is an S, so all four corners would have come with "drilled" rotors.

FTD · 11-13-2007, 06:54 AM

Quote:

Originally Posted by JMatta

If you do not track the car, they should be fine, other than thickness (which you've already pointed out).

Since I do track my 2004 Boxster, should I also replace rotors at the same time? Also I am looking at the Pagid pads and wonder which are best for part street, part track driving.