Planet 9

I was told when I changed my tires a month ago that my front brake pads were pretty worn. Now my brakes have started to squeal (they never squealed before) is this a sure fire sign they are now worn out or is there still some life in them and I can wait till the low brake warning light comes on.

Do heavily worn brakes squeal?

If you wait until the warning light comes on you will also be paying for sensors in addition to new pads. It takes 5 minutes to pull pads out and look at them (See Articles here if unfamiliar with the process) I would suggest looking at the pads and if they are about to trigger the sensors it is time to replace them.

It is impossible for any of us to know why your brakes are squeeling.

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K-Man S

I just recently replaced my pads, which were almost down to the wear sensor holes (I don't have the actual sensors in mine) - and they never squealed, except maybe just a little when they were very cold.

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2006 Cayman S Tiptronic (Year-round Daily Driver & Part-time Track Toy)
Mods: SRP, DREAM-1, VentureShield, Xpel Headlamp shields, 35% Tint, MotorDrive Front Mesh Grills, Bumperplugs..
Track Prep: Pagid Yellows, Champion RS98s/NT05s, Deka ETX14 Battery, CG-Lock, Extinguisher, Rennline towhook, BBI Harness/Rollbar

I also have the squeaking/squealing noise too. I don't think that my pads are worn, and no light has come on for low braking oil/fluid. What other things could this be due to besides worn out brake pads?

I just checked my pads today and they are fine, and I think my braking oil/fluid levels are good too, but occassionally I'll hear a squeaking sound when I brake. It's not major and does not affect braking performance, but what could this be due to?

The Cayman's too new to have squealing brakes -- is to at DIY car wash put switch to wash and spray down wheels and brakes. No need to jam nozzle down in between pads but just hose every caliper down real good then switch to rinse and use clear wash to thoroughly rinse away soap and brake dust.

Finish washing process with a good spray down of no spot rinse water and when done take car out and use brakes enough to really dry them out. If you don't rotors rust where pads contact and this can lead to pulsing brakes.

Another trick is to take car out and "bed" in brakes again. Run car up to speed then brake hard, no ABS though, and do not come to a stop. As quick as you can accelerate up to speed again and repeat the process.

You should feel a change (for the better) in braking bite and any squealing will/should have gone away.

This of course assumes you've carefully checked brakes, rotor surfaces outside and inside for any signs of scoring or overheating, etc.

Sincerely,

Rockster.

Rockster,
Wouldn't any rust be quickly scrubbed off the first time the brakes are applied ? How long could the 'pulsing' last ? Permanently ? Please explain further how rust can cause pulsation. TIA

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I respectfully disagree. After decades of motorcycle racing and doing my own work on the bikes I've had a little experience with brake pads. One thing every professional tech has expressed to me is to avoid using any detergent on brake pads. I agree with washing down your calipers but high pressure soap sprays and especially a no-spot rinse is, IMO, a no-no.

When I wash my car I start with the wheels and try to avoid getting any soap on the rotors, calipers and pads. If the calipers are dirty I remove the wheel and spray down the caliper with brake cleaner and then wipe them down with a dry rag. That's how you clean calipers. You can also leave the wheel on and spray them down AFTER you wash. The brake cleaner will help to dry the pads and rotors.

Blowing out the brakes with compressed air or a leaf blower will minimize rust on the rotors and if you take a short ride after washing that should clean off your rotors. Of course whatever rust did form on the rotors will end up on your just cleaned wheels but a little detailing will take care of that.

I switch back and forth between OEM and track pads. When I put the OEMs back in last week they squeeked. I'm thinking I need to re-glue the spiders onto the back of the pads which I intend to do this weekend.

Rockster thank you so much, I tried hard braking but without stopping, and then accelerating, and then hard braking as you suggested. I think it might have worked, I have to drive more in the car before I can tell you if my brake squeaking/squealing is completely fixed. But it's looking good. Thanks.

I'm by no means an expert, but my guess is that its some kind of "layer" that forms on the pads. Think removing the pads, cleaning them with a sand paper or so does the trick!

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That's pretty much what happens. The scenario is called "glazing". If you operate brakes too lightly for too long they develop a coating that doesn't help the friction coefficient. The solution is to de-glaze them, and the best way is to apply copious heat to the pad in a gentle fashion. ie. Brake hard (but no ABS!) a few times in succession to get plenty of heat in and break-down the bonds that make the glaze.

I wouldn't sand the pads though, you'll end up with much surface roughness, and that'll dig into the rotor until it's smoothed down again. Just let the pads to the surface scouring for you!

My car was a year old with 1700 miles on the clock and had been treated very gently when I bought it. The brakes were heavily glazed and the braking improved massively after a few 100-0 bedding-in brakes.

As an interesting part of trivia: Carbon ceramic brakes suffer extremely badly from brake glazing and are hugely hard to de-glaze. I talked with a Bentley engineer and he said their Carbons are problematic unless the customer is a seriously fast driver: Unless you break really hard they glaze and squeal very loudly. Most customers bring them in, and deglazing literally is 4-5, or more, successive 160mph-to-still hard brakings to condition the pads. Horrifying. I feel for the poor techies that have to lose their lunch over that.

My OEM Brakes are squealing too. 2008 Boxster S with under 6k miles and only a hand full of track days. Pads are getting replaced (Pagids) but aren't near sensors yet. I will try the bedding process but my question is about the Rotors. I wouldn't call them badly grooved but the are no longer totally flat. How much grooving is normal and at what point does that become a concern?