Brake rotor "break-in" ?

[PeaveyBassist]

I just got new rotors and I am gonna put em on today (front ones only). Is there anything I need to do right after putting them on to "break them in" ? Or do you just put em on and drive? If anyone is wondering...these are the Balo OE replacements from www.bimmerparts.com

Will

[hamann318is]

From what I've read, the best idea is to do rotors and pads at the same time. Pads require a break in, and if you're going to get new rotors, might as well get new pads.

The general idea behind the pad break in is slowly driving and stopping; this is followed by higher speed breaking to not a complete stop. There are articles around that give more detail, but that's what it is in general.

[PeaveyBassist]

Just swapped rotors. At first, holy crap they stopped faster than the old ones no doubt. But... After driving for 5 minutes and 1 or 2 40-0 hard braking stops, it felt like I had to push the pedal all the way, and it still wouldnt stop as fast as it was 2 minutes before. So I decided to drive home slower and check what was goin on. I got halfway home and it smelled like leaves burning so I'm like... I better check and make sure nothing is being ruined now. I get out, smell each wheel/brake and the front passenger side has steam coming off of it and it smells WAYYYYYYY hot. So I drive home extra slow. Take the wheel off, and it looksl ike the pads are rubbing. So I take off the caliper and basically put it back on. Then I go drive a little bit and it does the same thing. What could be the problem? Could it be the caliper itself? It shouldnt heat up that fast I know.

Will

[hamann318is]

The bad smell is what should happen with new rotors. I'm not sure about the heating issues you're having.

[Fred]

The bad smell is what should happen with new rotors. I'm not sure about the heating issues you're having.

Yup. After you properly bed the pads and rotors in it should smoke a little. From Pagid's website:

BRAKE PAD BEDDING IN PROCEDURE

To ensure maximum performance and customer satisfaction, new brake pads must be bedded in upon installation. Correct bedding guarantees that new brake pads and new rotors work flawlessly together. In order to function optimally, organic brake pads must develop friction coal on its surface. This friction coal develops at a temperature of approximately 280°C (537°F). It is very important that this temperature is reached continuously and slowly. This gradual process generates temperatures that not only penetrate the surface of the brake discs and pads, but also distribute evenly through the whole disc and pad material. This is essential when using new brake discs, since the disc often shows signs of stress (due to the casting process and fast cooling) in the materials. A steady and careful warming and cooling process guarantees a good release of both materials.

The bedding in/break in procedure should be done as follows:

Drive at approx. 35 mph (60 kmh) for about 500 yards (solid front discs) to 800 yards (vented front discs) while slightly dragging the brakes (i.e. light brake pedal pressure). This process allows the brake temperature to slowly and evenly build up to 300°C (572°F).

Now, if possible, drive about 2200 yards maintaining the same speed without braking. This will allow the pads and discs to cool down evenly. After this cool-down, perform a normal brake application from 35 mph to 0. No panic stops!

Now, the friction surface has evenly developed friction coal, the pads have bonded with the disc surface, and tensions in the disc materials will have disappeared.
Only trained master mechanics should perform this procedure before delivering the vehicle to its owner. Do not expect your customer to properly finish your brake job!
This bedding process is only suitable for the front axle - not the rear. This is due to the brake force distribution of front and rear axles. In order to reach 300°C (527°F) on the rear pads you would have to drive several miles with dragging brakes. However, in that time the front brakes will be glowing red, overheating and thus destroying the front brakes.

Final note – don’t forget to clean hubs and check the wheel bearings. Also, the brake fluid should be replaced at least every 2 years.

UPDATED 2/3/03

[///M42 sport]

did you compress the caliper when you changed out the pads?

[DEV0 E30]

did you compress the caliper when you changed out the pads?

[Schniddy]

did you compress the caliper when you changed out the pads?

what that mean?

[DEV0 E30]

You know how the old pads may be 1/2 the size of the new? Width wise? You have to compress the caliper with a clamp or other tool to get them on there correctly.

[///M42 sport]

when you swap out your worn pads, the caliper is compressed to a certain extent. You need to open up the brake resevior and compress the inside pad so that the new pad can fit and be compressed the normal distance. You just need some clamps or really big pliers.

[DEV0 E30]

when you swap out your worn pads, the caliper is compressed to a certain extent. You need to open up the brake resevior and compress the inside pad so that the new pad can fit and be compressed the normal distance. You just need some clamps or really big pliers.

Scientific post that kicked my posts ass right there. :P

[Schniddy]

You know how the old pads may be 1/2 the size of the new? Width wise? You have to compress the caliper with a clamp or other tool to get them on there correctly.

I totaly get the concept but not quite sure how it would be done.
But hey, I'll learn with time ;)

[Bavarian3]

caliper doesn't compress....

the piston compresses..... :)

[PeaveyBassist]

1. old thread :)
2. I pushed the piston in when I did it.
3. I think there was just some little coating on the rotors when I put em on because I didnt clean them off. After that first day I had em on, everything was fine and dandy.

Will

[T.Dot E30]

Ya you were probably braking too hard. Your suppose to take it easy for 300-400 kms.