Our 2008 Subaru WRX STI has massive 4-piston fixed calipers that really get the job done. No fade, no drama. They just work.
But they are starting to emit a rough growl in certain conditions, specifically the last few feet before a complete stop. It's not the fingernails-on-chalkboard "squeeeeeeee" that indicates the wear indiator has introduced itself to the rotors, mind you. It's something else.
I decided to have a look.
The rotors look decent, with no excessive discoloration or grooves, to speak of. But the front brakes pads are looking a little ... thin.
There isn't a lot of meat left. The chamfers on the leading and trailing edges of the pads are about gone. Same goes for the slit that bisects the friction surface into two halfs on most brake pads.
Since these features are primarly NV (noise & vibration) countermeasures, I expect that their deteriorated state explains the gravelly groan--there's nothing else visible to explain it.
The pad wear indicator is not terribly close to the rotor, but there is only enough pad left for 2 or 3 weeks--a month, tops. We'll order new ones and swap them out right here after the holidays. Stay tuned.
Dan Edmunds, Director of Vehicle Testing @ 17,100 or thereabouts
jaguar36 says:
05:54 AM, 12/18/08
Yay more DIY posts!
While I enjoy reading about various service experiences, I think seeing some DIY stuff is also quit useful.
sbcooke says:
05:55 AM, 12/18/08
I am interested in this one. I am assuming/hoping that since we have the brembo brakes that changing pads out should be a reasonable DIY project. Or if I get it done at a shop, it should be less labor and cheaper.
roadburner says:
06:07 AM, 12/18/08
sbcooke,
Replacing pads on a fixed caliper is a dead easy DIY. There's no reason to pay someone to do it.
tenfifteen says:
06:17 AM, 12/18/08
The 'growl' could simply be deposits on the rotor, but it sounds like you need to replace pads anyway (and you'll have to bed those in of course), so we may never know.
Plug for Zeckhausen Racing if you haven't already ordered them. The owner (Dave Zeckhausen) is one of the most knowledgeable guys on brakes you'll come across, and is a pleasure to deal with.
Post up the DIY, too... it is easy and there's absolutely no reason for any self-respecting car guy or gal to pay someone to do it.
stingray454 says:
07:06 AM, 12/18/08
There's at least 30-35% left on those. I wouldn't replace them yet, unless you plan on taking it to a road course soon.
vvk says:
07:09 AM, 12/18/08
I hope you guys are aware that Subaru covers first brake pad replacement under 36/36k warranty. Read your warranty booklet. You are welcome :)
roadburner says:
07:47 AM, 12/18/08
tenfifteen,
You are dead right about Zeckhausen Racing. Dave is a great guy. When I was thinking that I was going to keep the Mazdaspeed he did a bit of research and found some great track pads for a reasonable price.
7driver says:
08:09 AM, 12/18/08
"Yay more DIY posts!"
I'll bet Dan just posted this to show up Erin's filter changing :-)
sworley says:
08:15 AM, 12/18/08
There is alot of meat left on those pads. Month tops if your driving a circuit race every day!
roadburner says:
08:26 AM, 12/18/08
stingray454,
Yeah, those pads have quite a bit of material left. If I was going to the track I'd bring an extra set of pads but for a street-driven car they are fine.
lazyhater says:
09:18 AM, 12/18/08
Planty of meat left, at least 5k more street miles.... Yeh for DIY! But if the dealer would do it for free....... I'll probably still DIY for a better job!
tenfifteen says:
09:50 AM, 12/18/08
If there is indeed plenty of meat left (I don't know how thin is "thin" on these), then we're back at possible pad deposits on the rotor(s), and maybe you just try bedding them in again...
http://www.zeckhausen.com/avoiding_brake_judder.htm
http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml
Roadburner... yeah, he's a great dude. Spent a half hour with me on the phone discussing pads for my M3, steered me away from a more expensive product I was considering that would've been disastrous at the track.
actualsize says:
10:34 AM, 12/18/08
The remaining friction material is thinner than the backing plate: about 1/8th inch is left, tops. I'm not seeing 5k miles here, and the noise isn't getting any better. Besides, the STI will accumulate more than 2,000 miles in a month.
subytrojan says:
11:33 AM, 12/18/08
vvk, Subaru's warranty covers brake pad replacement in the first 3 years/36,000 miles (whichever comes first) due to normal wear and tear. I doubt we can say the STI has been subjugated to "normal" wear and tear.
I think something that should also be mentioned here is how much easier it is to access and change the brake pads of fixed brake calipers compared to sliding ones. I wish all manufacturers used fixed calipers! :o)
tenfifteen, Dave Zeckhausen is indeed a great guy. I've sold OEM BMW parts to him over the phone when I worked at Pacific BMW in Glendale, California.
MS3lvr92 says:
05:01 PM, 12/18/08
haha... maybe they're wearing a little thin because of all those hard stops? You know the ones when you sort of break loose 2nd or 3rd gear around a sweeping bend and spot a Crown Vic in the oncoming lane? I've had a couple of those.
jdub53084 says:
06:03 PM, 12/18/08
the rotors look like they're glazed, or lightly scored too.
BTW, check the shims and anti-rattle clips, those little critters can drive a person crazy trying to find NVH noises... been there, done that!
vvk says:
06:49 PM, 12/19/08
subytrojan,
Yeah, I would not mention anything about being from Edmunds and taking the car to the track, etc. :) I have many Subarus in my family -- they all got their first pad replacements for free. Of course my personal cars usually take about 100k miles to wear out the first set of brake pads, so no luck there :)
As far as fixed vs. sliding calipers, having done both numerous times I can say that Subaru sliding calipers are extremely easy to work on. The pistons pivot out of the way, so the pads are very accessible. It is a DIY friendly design.
And don't go cutting those brake rotors now. Replace them! It is the only way to go these days.