**** SOLVED**** (Added a few pics) New Brakes make "whirling" sound

[LakeSurfer]

replaced both front and rear rotors and pads with OEM a couple days ago. when I compressed the pistons I shoot fluid out of the reservoir and onto the floor. When I completed the job I took it out to accomplish the bedding in process. When I hit the brakes with force i hear a whirling sound, much like a turbine engine shutting down. I was told that the fluid that leaked out the reservoir spilled onto the vacuum sensor and shorted it out. I replaced the sensor but the noise persists. There is no vibration or steering wheel shimmy or anything out of the normal that I can tell. car drives straight and when I hammer the brakes it stops in a straight line as well.

Is this a normal(ish) sound I know the manual talks about brake noises but the old pads and rotors where just as quiet as any other car.

thanks

-Mark


****SOLVED****

it rained the other day and the rear rotors had the usual light surface rust on them. I drove to work and for some reason looked again at the rear rotors and noticed that only the outer layer of rust had come off from the brake pad. I checked the otherside and it to had rust remaining on the inner surface only.



Clearly i had done something wrong upon install, I jacked the car up and did 2 things. First i confirmed that the caliper bracket (#10 below) and the clips WILL fit perfectly fine on either the right or left side, at least the rears.



Even though there is only 1 part number for the bracket and they are universal, I swapped the right to the left and the left to the right. Perhaps they became a matched set throughout the years?

Next I was the metal clip. I noticed it can be installed 2 different ways. below is correct and not the way I originally installed them..



The clips Have what i call "legs" and these legs can be installed 2 different ways. First if you look at the "legs" you will notice that on the ends of them they have a "joggle" or a "step". this joggle/step, when installed correctly looks wrong because half of it is sort of floating. but if you install them incorrectly like I did, you can slide the leg right where the red arrows are in the image below. the caliper is actually notched out and fits the steps on the clips legs perfectly, which is why I installed them that way. so I took them out and reinstalled them the right way.



the brakes are fixed

No more noises and the rotor wear is now uniform and the brakes are wayyy more effective but I'm not sure if the clip or the bracket swap fixed the issue but it's fixed and I'm happy.

now that i have a better understanding its time to take them completely apart to prep for paint. Ill take a little care to ensure they are labeled right and left.

-Mark

[m235boy]

Originally Posted by LakeSurfer

replaced both front and rear rotors and pads with OEM a couple days ago. when I compressed the pistons I shoot fluid out of the reservoir and onto the floor. When I completed the job I took it out to accomplish the bedding in process. When I hit the brakes with force i hear a whirling sound, much like a turbine engine shutting down. I was told that the fluid that leaked out the reservoir spilled onto the vacuum sensor and shorted it out. I replaced the sensor but the noise persists. There is no vibration or steering wheel shimmy or anything out of the normal that I can tell. car drives straight and when I hammer the brakes it stops in a straight line as well.

Is this a normal(ish) sound I know the manual talks about brake noises but the old pads and rotors where just as quiet as any other car.

thanks

-Mark

I believe it's normal, the rotors are new so they have a rough surface, wait a bit they'll wear down and noise should go away.

[Dpc2u]

The sensor definitely needed to be changed if it got fluid on it, but that would cause the vacuum pump to run excessively and get progressively worse. In many cases, even though you did the proper bed in procedure, the drilled rotors will cause the whirring you describe until everything gets worn in and will eventually go away. Not at all unusual.

[LakeSurfer]

Originally Posted by Dpc2u

The sensor definitely needed to be changed if it got fluid on it, but that would cause the vacuum pump to run excessively and get progressively worse. In many cases, even though you did the proper bed in procedure, the drilled rotors will cause the whirring you describe until everything gets worn in and will eventually go away. Not at all unusual.

That's awesome to hear.

At first I was upset that I spent time and money on the sensor but the sensor was wet when I took it out and I'm sure you're right that eventually it would've gone bad.

Based on all the grime and old looking fluid in that area it looks like this wasn't the first time it happened. I'm making a little plastic "deflector" shield under the reservoir to prevent future problems as I'll be flushing the fluid when I have some free time.

Thanks.

[Scrippy]

The noise is due to the prepped surface finish. The fluid coming out is probably due to you compressing then pots too fast. Next time compress them slower.

[LakeSurfer]

Originally Posted by Scrippy

The noise is due to the prepped surface finish. The fluid coming out is probably due to you compressing then pots too fast. Next time compress them slower.

They did have some type of protective gray film on the rotors. I had to use all kinds of chemicals to remove it.

The noise is still there. Now I'm wondering if something is loose or if I didn't get all the film completely off the rotors. Be never seen anything like it. It was messy and stubborn.

I'll check it out this weekend as I'll be flushing the guild and bleeding them.

[Scharbag]

Originally Posted by LakeSurfer

They did have some type of protective gray film on the rotors. I had to use all kinds of chemicals to remove it.

The noise is still there. Now I'm wondering if something is loose or if I didn't get all the film completely off the rotors. Be never seen anything like it. It was messy and stubborn.

I'll check it out this weekend as I'll be flushing the guild and bleeding them.

You do not need to remove anything from the rotors. Quick rinse with a shot of brake clean to make sure there is no oil on them. Put in the pads and then go bed them in properly. Bedding in pads requires some good hard stops.

Here is how Hawk recommends bedding in brakes.

Cheers,

[GORDON.M3]

Sounds like you didn't follow the bedding process properly.

[LakeSurfer]

Originally Posted by Scharbag

You do not need to remove anything from the rotors. Quick rinse with a shot of brake clean to make sure there is no oil on them. Put in the pads and then go bed them in properly. Bedding in pads requires some good hard stops.

Here is how Hawk recommends bedding in brakes.

Cheers,

you do need to remove the film that was on the rotors per the instructions in the box. I've never seen it before on any rotors I've ever replaced. It was a matte gray film that was on the entire rotor.

at first i hit them with brake cleaner and then reassembled 3 of the four brakes, I got to the 4th brake and spun the rotor with the pads installed and they rubbed onto the rotor and scratched this gray finish off and I could see the polished surface of the steel rotor so i took everything apart on all 4 corners and used brake cleaner and goo gone and a final brake cleaner to clean it all off. there was zero oil on the rotors out the box only the gray dry film and the first time i hit them with brake cleaner, nothing came off. i used an entire roll of shop towels and an entire bottle of brake cleaner to get this crap off. they are brand new OEM rotors and pads.

[LakeSurfer]

Originally Posted by GORDON.M3

Sounds like you didn't follow the bedding process properly.

based on?????

I bed them the way I always do and never had any issues in the past. a bunch of stops from about 40mph ish with more than average brake pressure followed by a few hard stops from 50mph ish.

ill be taking it apart this weekend to flush them so ill have a chance to recheck everything.

[Scharbag]

Originally Posted by LakeSurfer

you do need to remove the film that was on the rotors per the instructions in the box. I've never seen it before on any rotors I've ever replaced. It was a matte gray film that was on the entire rotor.

at first i hit them with brake cleaner and then reassembled 3 of the four brakes, I got to the 4th brake and spun the rotor with the pads installed and they rubbed onto the rotor and scratched this gray finish off and I could see the polished surface of the steel rotor so i took everything apart on all 4 corners and used brake cleaner and goo gone and a final brake cleaner to clean it all off. there was zero oil on the rotors out the box only the gray dry film and the first time i hit them with brake cleaner, nothing came off. i used an entire roll of shop towels and an entire bottle of brake cleaner to get this crap off. they are brand new OEM rotors and pads.

Man, I stand corrected. I have never had to remove a coating before install - and I have installed a lot of rotors with racing. But I race Japanese slag. Talked to a mechanic buddy and he said he has run into a few rotors that come with a shipping film. Seems like a terrible idea.

What brand of rotors? Zimmerman or actual BMW?

Hope you can get it figured out.

Cheers,

[LakeSurfer]

Originally Posted by Scharbag

Man, I stand corrected. I have never had to remove a coating before install - and I have installed a lot of rotors with racing. But I race Japanese slag. Talked to a mechanic buddy and he said he has run into a few rotors that come with a shipping film. Seems like a terrible idea.

What brand of rotors? Zimmerman or actual BMW?

Hope you can get it figured out.

Cheers,

Yeah it was a mess. If i has to do it over again I'd submerge them in something more effective.

I bought "OEM" from FCP Euro and the rotors came in Zimmerman boxes. The (what I assume are part numbers) stamped on the rotors have different numbers than what I pulled off. I'm assuming I pulled off the originals because they were pretty worn out. And only had 35k miles on the car.

[pbonsalb]

I am not sure there is anything for the OP to worry about. He installed new rotors and pads. Of course the pistons needed to be compressed more for the full thickness pads and rotors. Of course that could result in brake fluid overflowing out of the reservoir if it was full. Should have siphoned some out. New pads and rotors may make a whirling sound until they break in a bit. The sound should go away, assuming they were installed correctly. Yes, you want to clean new rotors with brake cleaner or something similar.

[KawBoy]

Originally Posted by pbonsalb

I am not sure there is anything for the OP to worry about. He installed new rotors and pads. Of course the pistons needed to be compressed more for the full thickness pads and rotors. Of course that could result in brake fluid overflowing out of the reservoir if it was full. Should have siphoned some out. New pads and rotors may make a whirling sound until they break in a bit. The sound should go away, assuming they were installed correctly. Yes, you want to clean new rotors with brake cleaner or something similar.

This.

[BayE30]

almost every new brake rotor i have ever installed (1000 maybe?) have needed to be cleaned before install(exeption being coated rotors usually a light grey coating). It is stated on the brake rotor package. They have a corrosion protection applied (light film grease) to prevent them from rusting in the packaging. A good spray down with brake cleaner and wipe with clean rags and yer good to go.

[SAMM3Y]

Unless they're zinc coated they all need washing with a mild degreaser to remove the mineral oil then brakleen. The oil is to stop them rusting whilst sitting. Stoptech's bed in process is 60mph to 0 as hard as you can 10 times consecutively then allow to cool down then repeat 10x.

I recently had pad material stuck on a rear rotor which made an awful whirring sound. Tried to hit it with some cleaner just cuz it was handy and it didn't touch it to no surprise. It took 150+ miles of driving to lose it being conscious about braking hard.

[Scharbag]

Originally Posted by BayE30

almost every new brake rotor i have ever installed (1000 maybe?) have needed to be cleaned before install(exeption being coated rotors usually a light grey coating). It is stated on the brake rotor package. They have a corrosion protection applied (light film grease) to prevent them from rusting in the packaging. A good spray down with brake cleaner and wipe with clean rags and yer good to go.

Yeah, a quick clean with brake cleaner is one thing - goo gone is another!!

[LakeSurfer]

There was no oil, grease or anything else like it applied to the rotors. I repeat NO oil was applied to the rotors. They where dry, super dry. So dry that I was shocked.

As I've previously stated I cleaned them with brake fluid and installed them and nothing changed. One did have a light scratch on it and I noticed a shiny silver rotor underneath. I took more brake cleaner and scrubbed on it. The brake cleaner only moved the "paint" around the rotor and did not take it off. I moved to a more aggressive chemical.

After research the gray stuff is an anti corrosion type "paint" on the entire rotor. Some people say to remove it and others do not.

[pbonsalb]

Leave the gray. The rotor surface will be scraped clean by the pads but the gray will delay rust on the hubs and in the vanes. The whirling sound should go away with some usage unless there is some other problem likes bad wheel bearing allowing excess movement. You can jack the car and shake the wheel to test for bearing play.

[LakeSurfer]

Are the caliper brackets universal?

I took the rear brackets completely off the piston assembly and cleaned them when I did the brake job. I'm wondering if I switched them by mistake.

[Ximian]

Originally Posted by pbonsalb

Leave the gray. The rotor surface will be scraped clean by the pads but the gray will delay rust on the hubs and in the vanes. The whirling sound should go away with some usage unless there is some other problem likes bad wheel bearing allowing excess movement. You can jack the car and shake the wheel to test for bearing play.

Yeah, don't mess with the coating with chemicals.

When you first apply brake pressure, the coating on the Zimmermann rotors will accumulate on the leading edge of the brake pads and you'll probably have chunks stuck on the pad and elsewhere on the rotor depending on your burnishing procedure. Check the brake pad faces and check the rotor and the drilled holes for the coating. It wouldn't hurt to check the torque and fitment of all the parts.

How loud is the "whirling" sound? The drilled and/or slotted rotors create a "whirling" sensation under braking but there should be little noise.

On a side note, you can confirm that brake fluid ruined the vacuum pump sensor if the vacuum pump is constantly running when fully applying brakes.

[aggieshan]

Just another suggestion on the spilled brake fluid. The brake fluid can be washed away using water. It is hygroscopic. It can be dissolved into water easily as far as I know. I have spill some fluid in my brake fluid reservoir area. I simply used lots of water to wash it away.