SQUEALING BRAKES

996 C4S 2003 Recently replaced front discs with Zimmerman OEM. Pads changed as well....twice! Constant squealing at slow city stops. Any ideas how to eliminate the noise?

What pads? -td

need to bed the brake pads.... yeah what pads?

+1 ^

You need to Bed in the pads. My pads(EBC Redstuff) squealed like crazy when it was new.

FWIW, I don't think you need to be pads [even track pas] for just street use. It's all abrasion on the street. If you track it, you need to bed them to benefit from the adhesive properties of track pads. -td

Is bedding them when you go 80mph and slam on the brakes or are we talking something else?

http://www.tirerack.com/brakes/tech/....jsp?techid=85 Brake Pad and Rotor Bed-In Procedures All brake pads must be bedded-in with the rotor they will be used against to maximize brake performance. The bedding-in process involves a gradual build up of heat in the rotors and pad compound. This process will lay down a thin layer of transfer film on to the rotor surface. Following the bed-in procedures provided by the manufacturer will assure a smooth, even layer of transfer film on the rotor and will minimize brake judder. Here are a few things to keep in mind when installing new rotors and pads: When installing new pads, the rotors should be new or at least resurfaced to remove any transfer film from the previous set of brake pads. It is critical that the installer clean any rust, scale, or debris from the hub mounting surface thoroughly and check it for excessive run-out with a dial indicator gauge before installing the rotor. The new rotor should also be checked for excessive run-out using a dial indicator gauge before the caliper and pads are installed. If a rotor has excessive run-out of over .004" (.10mm) it should be replaced. If your new rotor has excessive run-out, please contact our customer service department for a replacement rotor. Do not install and drive using the rotor! Rotor manufacturers will not warranty a used rotor for excessive run-out. Running with excessive run-out on the hub or rotor will cause vibration issues. Failure to follow these procedures may result in brake judder, excessive noise, or other difficulties in bedding-in the new brake pads. The pads need a fresh surface to lay down an even transfer film. Residue from the previous pad compound on the surface or an irregular surface on a used rotor will cause the pads to grip-slip-grip-slip as they pass over the rotor surface under pressure. The resulting vibration will cause noise and telegraph vibrations through the suspension and steering wheel. This vibration is known as brake judder or brake shimmy. This is typically caused by an uneven transfer film on the rotor surface or an uneven surface on the rotor not allowing that transfer film to develop evenly. This is often misdiagnosed as a warped rotor. Bedding-in new pads and rotors should be done carefully and slowly. Rapid heat build up in the brake system can lead to warped rotors and or glazed brake pads. Most brake pad compounds will take up to 300-400 miles to fully develop an even transfer film on the rotors. Following are the recommended bed-in procedures from each manufacturer: AKEBONO 400 to 500 miles of moderate driving is recommended. Consumer should avoid heavy braking during this period. ATE 400 to 500 miles of moderate driving is recommended. Consumer should avoid heavy braking during this period. BREMBO Gran Turismo In a safe area, apply brakes moderately from 60mph to 30mph and then drive approximately 1/2 mile to allow the brakes to cool. Repeat this procedure approximately 30 times. HAWK After installing new pads make 6 to 10 stops from approximately 35 mph with moderate pressure. Make an additional two to three hard stops from approximately 40 to 45 mph. Do not allow the vehicle to come to a complete stop.When completed with this process, park the vehicle and allow the brakes to cool completely before driving on them again. Do not engage the parking brake until after this cooling process is compete. NOTE: Hawk racing pads (Blue, Black, HT-10, HT-12) may require a different bed-in procedure. Contact your sales specialists at the Tire Rack for racing application information. POWER SLOT Follow the brake pad manufacturer's recommended break-in procedure taking care not to produce excessive heat in the system. Avoid heavy braking for the first 400-500 miles. SATISFIED For Gransport GS6 Carbon Ceramic Pads — Step 1: Make 10 stops from 30 mph (50 kph) down to about 10 mph (15 kph) using moderate braking pressure and allowing approximately 30 seconds between stops for cooling. Do not drag your pads during these stops. After the 10th stop, allow 15 minutes for your braking system to cool down. Step 2: Make 5 consecutive stops from 50 mph (80 kph) down to 10 mph (15 kph). After the 5th stop, allow your braking system to cool for approximately 30 minutes. This completes the break-in of your pads to the rotor surface. During Steps 1 & 2, a de-gassing process occurs which may produce an odor coming from your pads as they complete the break-in cycle. This odor is normal and is part of the process your pads must go through to achieve their ultimate level of performance. The odor will go away after allowing your braking system to cool for approximately 30 minutes. As with any new set of pads, do not tow a trailer or do any hauling during the break-in period. Full seating of your new brake pads normally occurs within 1,000 miles. For all other Satisfied pads — 400 to 500 miles of moderate driving is recommended. Consumer should avoid heavy braking during this period.

Quotes source post: 8517045

That article is a bit silly for street only vehicles / use. At low temps and with complete abrasive use only, any transfer layer is eaten away. You need to re-bed for performance use. http://www.stoptech.com/tech_info/wp_bedinfaq.shtml See here: http://www.stoptech.com/tech_info/wp_bedinstock.shtml -td

Quotes source post: 8516161

Did you throughly clean the pistons/boots with some brake cleaner. The pistons/boots can develop a healthy coating of brake dust that can interfere with the natural tendency of the pistons to retract from the rotor face slightly when the brakes are released. This can result in a bit of squeal at low speeds and light braking. If they squeal at other times one always has to consider the wrong parts were used, or they were not installed correctly. If you're sure the brakes are ok then a bedding in process I think would help. I do it have done it after every brake job I've ever done. Nothing fancy -- unless the pad/rotor maker supplies you with a specific brake bed in procedure. I just take the car out where I can accelerate the car safely up to highway speeds then apply the brakes relatively hard to slow the car down in a big hurry. I am careful to never bring the car to a stop but release the brake pedal at say under 30 miles an hour. I repeat the above a couple of times and each time I can feel the brakes bite harder. I don't think I've ever had to go over 4 times and most of the time 3 is sufficient. Then I drive the car long enough to cool down the brakes completely and done. Sincerely, Macster.