Brembo drill directional
 

is this a right direction? I just install them yesterday follow the brembo instruction. The left side of the picture is my front bumper.

Does it drive weird at first put on, after awhile will it get smoother? Right now I am experience rotor and pad is a little rough at first couple miles, seems like they are trying to break in.

REAR LEFT WHEEL is a top picture and FRONT LEFT WHEEL is on bottom

Before you get too many miles on your new brake assemblies, follow this brake pad bedding procedure from a BMW expert Dave Zeckhausen:

http://www.zeckhausen.com/bedding_in_brakes.htm

I have slotted rotors and if the install direction is the same for cross drilled, then you have them on backwards.

instruction said the first hole near out edge will be first one enter the pad. As I understand rotor will turn opposite spiral due to dissipate the heat. According to the instruction I know my rear brake installation is corrected, but the front brake holes are weird to me, which I am not sure about

you have them going the right way:thumbup:
but you need to bed in your pad ASAP...

Your question, and the answers posted above, appear to be based on the direction of the drilled holes. From what I know of brake rotors, the direction of the drilled pattern isn't the issue. The drilled holes don't dissipate heat, they are for looks (unless you have racing pads that produce gases, not a factor on the street). What dissipates heat are the fins. Furthermore, the fins impact the steady-state heat capacity of the rotor, while what is more important is thermal mass. The mass has been reduced by drilling holes, thus meaning that while the rotors can cool faster, they will also attain fading temperatures faster. This isn't usually important in street driving, and they do look nice.

Some rotors have cooling fins (the fins between the two friction surfaces) that are flat, or radial. Those rotors can be mounted in either direction. If a rotor has curved fins, then it is directional. Mounted the wrong way, the rotor will not have the same cooling characteristics and performance will suffer (unless you drive high speed in reverse all the time). The fins aren't designed to work like a ram air scoop, they are designed to encourage the air stream to draw air out through the rotor edge.

It is difficult to tell from your pictures which way the fins are running (I assume they are curved). The problem is that the drilled pattern may or may not match up with the fin pattern. Often, a rotor that is designed to have holes or slots has a heavier fin, and the hole pattern runs the same way as the curved fin. The holes are then spaced around the fins. If a rotor wasn't designed to be drilled, but is drilled afterwards, the theory is that the hole pattern may intentionally go opposite to the fin pattern, so as not to weaken the rotor too much, which causes cracking. While all this is somewhat theoretical, you then have to add in the fact that the company drilling the holes may or may not know or care about this. Brembo rotors with holes/slots can be made that way by Brembo, or modified by a third party. See all the low priced offers on ebay. Hence, it is anyone's guess what yours look like where the fin is.

Check the fins. See if they look like the picture below. All of the above means that you may have a different appearance front to rear (in terms of the drilled hole pattern) but both may be mounted correctly.

Jeff

Hey guys,
After I change the rotors, now my brake fluid is way up pass MAX. Should I take some out? Due to piston was not stick out so much after I readjust them to fit the new brake shoes, therefore, more fluid remains in reservoir.

Yes.

So, were the rotors installed correctly or not?

Yes, my rotor was install correctly because the vane are bi-directional. Mater is the hole directional was place at right direction, which, I did.

Are the stock BMW rotors directional?

Thanks for that link Asawadude, I have made a copy and saved for when I next change pads/rotors (discs in the UK).

Don

I think there were confussions when you are purchasing the after market parts. I learned that the Brembo sells the blank rotors to the distributor, the blank one does not have directional due to the vane. After holes were drilled by distributor then they determine which direction should be.
Here is a picture of the vane looklike

My brake still smell burning after 1200 miles driving with new brake, It's only smell when I done some hard driving. Is it true these cross drill rotors get hot quicker than the plain one when hard driving apply more frequently?

Thanks for inputs

Yes. That may or may not be a factor in the burning smell, but they will overheat more quickly. There simply isn't the same mass there to absorb the energy. That matters more than the surface area added by drilling the holes. The good news is that after you have overheated them, they cool down more quickly as well.

not sure why people think crossed drilled are better than solid, i guess it must be for looks but for such a heavy car unless you go for the full big brake kit i wouldnt use cross drilled. your better off using a solid rotor and ungrade the pads IMO

Braking is turning kinetic energy into heat, which creates gases which need to be dissipated which is accomplished by the holes in drilled rotors.

Just ask the BMW/Mercedes/Ferrari/Lamborghini/SRT/SVT engineers who use them as stadard equipment on performance cars.

JV

But With Todays Pads There Are Less Gases So No Need For Crossed Drilled For Normal Street Use, A Sports Car Or Track Car Yes But Not A 2 Ton Suv. A 2 TON SUV IS NOT A PERFORMANCE CAR.

Less gas doesn't mean no gas and it seems to me your real problem is the application (on an SAV) as opposed to the performance differential in the rotors. Many where on the forums would disagree with your statement that the X5 is not a performance car, too. So would BMW.

People spend their $$ how they want to in the end. I have no complaints on my Brembo drilled rotors and with the OEM pads and calipers I've had better braking feel. They were cheaper than OEM solid rotors cause I got them wholesale.

JV

If Crossed Drilled Were Better Why Does The 4.8 Not Have Them? Even On My F355 I Have Solid Rotors. Iam Not Saying Dont Use Them Iam Saying Imo Its Not The Way To Go Unless You Opt For The Full Big Brake Kit Most People Use Them For Looks And Thats Fine But They Are Not Better Than Solid For Normal Street Use.

I Guess We'll Have To Agree To Disagree:)

Unless you've had solid rotors and switched to drilled or vice versa, how would you really know which one is better?

JV

Because On My Track Car I Use Cross Drilled With Track Pads (lotus Elise) On My Ferrari I Left The Solid Rotors On And Ungraded To The Porterfield R-4s Pads On The 4.8 I Switched To The Porterfield R-4s Pads Also. The Ferrari And The X5 I Drive On The Street Only And I Dont Need Cross Drilled It Wouldnt Make Any Difference. I Dont Mind The Look Of Cross Drilled All Iam Saying Is For Normal Street Use You Really Dont Need Them. And Its Just My Opinon.

Hayaku races a lot in his P-Car and he basically says the same thing you do about not needing them on the street, so you're in good company.

I'm simply stating that I have used both on my X5 4.4 and found the drilled rotors to give me better performance. It's not my opinion, it's a fact based on my actual experience.

JV

The Best Thing About Any Mod Is Your Happy. I Use Porterfield R4-s Pads And Stoptech S/s Hoses On The X And It Works For Me.

JV:

It is your money, and you should spend it how it makes you happy. Personally, I think that drilled rotors look good. Having said that, we should debunk the myth about outgassing on pads. Modern pads don't outgas. The gases were created from the binding materials in the pads, when they were at elevated temperatures, many decades ago. Not true anymore.

Drilled rotors also get claims of increased surface area for radiation. That is true when rotors are at a steady temperature. Trouble is, braking isn't a steady-state heating. Brake rotors tend to rapidly get hot, and then cool until the next application. Less thermal mass means faster temperature rise.

I would have thought that the removal of the boundary layer of water in the rain would be a better reason for drilled or slotted pads, but with the new brake-drying features on many high performance cars, even that is going away as a justification.

Your brake feel improvement is likely related to the surface finish. A good comparison would be to compare smooth Brembo rotors to drilled Brembo rotors, from the same source. Comparing the Brembo rotors to stock isn't as valid.

I still think they look good. It is just that people try to sell them as a performance improvement, when they aren't. They are a good cosmetic improvement, IMO. :thumbup: