[Raphael X4]

Hello,

I don't have a good way to machine rotors while changing my own brakes.

This will be my first brake change at around 50,000 km. (35k miles).
Rotors are not vibrating right now.


Anyone know if rotors could last two brake changes or 100,000 km (60k miles) without being machined, with calm driving habits?

[rezok]

recommend identifying the minimum legal thickness for the rotors and then measuring them to see if theyre road legal.

All good trying to save money, but brakes are important part of safety, so tread cautiously.

[Artdnj]

If doing it yourself isn't the rotor cost very affordable? I would do them at the same time.

[dmicah]

Don't you only need to machine them if they're vibrating?

[mct128i]

Originally Posted by Raphael X4

Hello,

I don't have a good way to machine rotors while changing my own brakes.

This will be my first brake change at around 50,000 km. (35k miles).
Rotors are not vibrating right now.


Anyone know if rotors could last two brake changes or 100,000 km (60k miles) without being machined, with calm driving habits?

In addition to concern over vibration due to warping, there is a minimum rotor thickness to be considered. The minimum thickness is usually stamped (in millimeters) onto the rotor "hat" and visible with the wheel removed - use an appropriate micrometer to measure the rotor thickness at several points to see if you are approaching the minimum.

[Burr001]

Originally Posted by Raphael X4

Hello,

I don't have a good way to machine rotors while changing my own brakes.

This will be my first brake change at around 50,000 km. (35k miles).
Rotors are not vibrating right now.


Anyone know if rotors could last two brake changes or 100,000 km (60k miles) without being machined, with calm driving habits?

I just installed my 2nd set of pads on the original rotors @ 40k miles with me driving like an ass. The rotors are not warped or have any deep grooves you should be fine, if there is a lip at the edges of the rotor and a difference in height where the pad contacts the rotor to where it doesn't then you need to change them. Best best is too measure thickness all around the rotor and see if they are in spec.

[SpencerPJ]

I would change the brakes with Akebono pads and carry on, you will get many more miles and dust free. No, I would not change rotors at 35k miles

[Sportstick]

Agree about the Akebono EUR pads and not machining rotors that are not warped. Machining them only reduces their ability to manage heat and shortens their life expectancy further.

[glennbk]

In the USA, vehicle inspection only takes a quick glance on the brake pads for thickness. Where as in Europe (British MOT and Germany), they measure every thing with calipers.
Just for safety, get a thickness and evaluation. If there is uneven thickness, it can damage your new pads.

[bouchy]

Machining is possible at place. It is used only to flatten (not sure if correct term) the edges. I'd recommend changing both, but 50kkm is not very good performance... so I see your point.

[cdnlouie]

Brake rotors can be cleaned up (if not heavily scored) with an abrasive wheel on a grinder, something 80 grit or higher and new pads installed. You just want to get the raised rust off to allow the pad to bed into the old rotor steel. Sanding disks mounted on a grinder do a fast job and they are good to go. If badly scored they might give some vibration that will bed in after a while but for perfect braking new rotors are nice.

[glennbk]

Were the wear sensors damaged?

[vrships]

the rotors are rated to be good for wear of 1.6mm, both front and rear.

So if your front rotor was 36mm when new, it should be > 34.4mm otherwise it needs replacement.

But some explain this thickness as "the minumium to allow for resrufacing, meaning that you can continue using it beyond 34.4mm if you don't machine them. Not sure if this is correct.

[g11hoonigan]

Originally Posted by vrships

the rotors are rated to be good for wear of 1.6mm, both front and rear.

So if your front rotor was 36mm when new, it should be > 34.4mm otherwise it needs replacement.

But some explain this thickness as "the minumium to allow for resrufacing, meaning that you can continue using it beyond 34.4mm if you don't machine them. Not sure if this is correct.

There can be legal implications so I'm pretty sure it's not just for resurfacing.

It's usually the minimum thickness that manufacturers can guarantee its proper operation and efficiency. Once it goes below the minimum, it can negatively affect its heat dissipation and structural integrity.

[TJay74]

AS long as the rotors are above the min discard spec, dont have signs of grooves or ridges on the rotor face and are not showing signs of uneven pad deposits then it is perfectly fine to install new pads on as long as you go thru the normal process of lubricating all of the appropriate points.

Once done just make sure to bed the pads in and then go about as normal.

[das boots]

Way back when, I remember that I used CRC or Permatex anti-squeak paste when I replaced brake pads. Does this still hold for newer BMW replacement pads?

BTW. Where is the brake fluid reservoir located in 2024 X3/X4?

Thanks.

[Rook24V]

I repair BMWs for a living. We typically use silglyde on our brake pads as anti-squeal compound when you install them. Apply it to all contact points on the pads (as in, where the pad backing plate contact the caliper, definitely NOT where the pad material contacts the rotor).

Brake rotors should ideally not be re-used if you can help it. They typically are past minimum wear after 1 set of brake pads. I might try to get away with it on rear brakes, but on the front brakes I would opt for new rotors unless they were amazingly well above minimum thickness.

If you do change the rotors out, get coated rotors. Zimmerman brand are great. ATE, Textar, Pagid, all make acceptable rotors as well. Coated rotors are going to FEEL like they're grinding on the first few stops, especially on your bed-in test drive, but that goes away very quickly.

Always replace the sensors, even if they haven't quite tripped off yet. The plastic in them is now EXTREMELY BRITTLE from the heat cycles they've experienced. Remember your brake pads get many hundreds of degrees under heavy braking, then cool off to room temp or cooler when not in use. This cycling makes the plastic very brittle. The liklihood of you breaking the sensor on removal is very high, or breaking when installing it. Sensor brand really doesn't matter, get the cheapest one.

Brake fluid reservoir is up by the windshield on the driver's side underneath the plastic covering. It should be flushed every 2 years, fyi.

If anyone has any specific questions let me know!

[Raphael X4]

Originally Posted by Rook24V

I repair BMWs for a living. We typically use silglyde on our brake pads as anti-squeal compound when you install them. Apply it to all contact points on the pads (as in, where the pad backing plate contact the caliper, definitely NOT where the pad material contacts the rotor).

Brake rotors should ideally not be re-used if you can help it. They typically are past minimum wear after 1 set of brake pads. I might try to get away with it on rear brakes, but on the front brakes I would opt for new rotors unless they were amazingly well above minimum thickness.

If you do change the rotors out, get coated rotors. Zimmerman brand are great. ATE, Textar, Pagid, all make acceptable rotors as well. Coated rotors are going to FEEL like they're grinding on the first few stops, especially on your bed-in test drive, but that goes away very quickly.

Always replace the sensors, even if they haven't quite tripped off yet. The plastic in them is now EXTREMELY BRITTLE from the heat cycles they've experienced. Remember your brake pads get many hundreds of degrees under heavy braking, then cool off to room temp or cooler when not in use. This cycling makes the plastic very brittle. The liklihood of you breaking the sensor on removal is very high, or breaking when installing it. Sensor brand really doesn't matter, get the cheapest one.

Brake fluid reservoir is up by the windshield on the driver's side underneath the plastic covering. It should be flushed every 2 years, fyi.

If anyone has any specific questions let me know!

Thank you for this.
I was hoping someone who actually does this for living would answer.

[das boots]

Originally Posted by Rook24V

I repair BMWs for a living. We typically use silglyde on our brake pads as anti-squeal compound when you install them. Apply it to all contact points on the pads (as in, where the pad backing plate contact the caliper, definitely NOT where the pad material contacts the rotor).

Brake rotors should ideally not be re-used if you can help it. They typically are past minimum wear after 1 set of brake pads. I might try to get away with it on rear brakes, but on the front brakes I would opt for new rotors unless they were amazingly well above minimum thickness.

If you do change the rotors out, get coated rotors. Zimmerman brand are great. ATE, Textar, Pagid, all make acceptable rotors as well. Coated rotors are going to FEEL like they're grinding on the first few stops, especially on your bed-in test drive, but that goes away very quickly.

Always replace the sensors, even if they haven't quite tripped off yet. The plastic in them is now EXTREMELY BRITTLE from the heat cycles they've experienced. Remember your brake pads get many hundreds of degrees under heavy braking, then cool off to room temp or cooler when not in use. This cycling makes the plastic very brittle. The liklihood of you breaking the sensor on removal is very high, or breaking when installing it. Sensor brand really doesn't matter, get the cheapest one.

Brake fluid reservoir is up by the windshield on the driver's side underneath the plastic covering. It should be flushed every 2 years, fyi.

If anyone has any specific questions let me know!

Thank you Rook24V. I will be replacing just the pads front & rear using the original BMW rotors since rotors have only 850 mi. Changing pads due to excessive BMW brake dust. And I do not even hard stop the brakes. Replacing with ceramic pads and new sensors.