Replacing brake rotors: Fact or Fiction?

[boardburton]

My brakes are getting low, I have been told that if I replace my pads and sensors that I should replace my rotors. I have never had to do this on any other car I have owned, but is this something particular to BMW's?

Do they just want more money out of me or is it a good idea.

[Rigmaster]

Not necessary, unless the rotors are warped or scored badly or below minimum thickness.

In fact some people say that it's best to replace EITHER rotors OR pads, but not both at the same time- not sure if I believe them though.

Bret.

[Fetch]

In fact some people say that it's best to replace EITHER rotors OR pads, but not both at the same time- not sure if I believe them though.
Bret.

hmmmm..I'm interested to what other people say about this, because I hope this isn't the case, as soon enough my pads will be pretty low, and my rotors have huge lips on them, so I'm assuming they are very worn down, so I am planning on replacing both at the same time.

I would think that as long as you followed that one bedding in process, that you would be good to go on the pad and rotor side of things?

[Rigmaster]

hmmmm..I'm interested to what other people say about this, because I hope this isn't the case, as soon enough my pads will be pretty low, and my rotors have huge lips on them, so I'm assuming they are very worn down, so I am planning on replacing both at the same time.

I would think that as long as you followed that one bedding in process, that you would be good to go on the pad and rotor side of things?

I agree with your line of thinking on this. I've done it this way many times over the years on many different cars and trucks and have not had any problems.


Bret.

[Blitzkrieg Bob]

both rotors and pads at the same time for many cars, and to add danger even the calipers too.

Most of the time I had too, wife runs em down till they are on rivets and the rotors are scored and blued.

[MTV]

I do have a rather irritating shimmy under braking which suggests a warped rotor. I was thinking of getting them cut since there is hardly any lip on them. But read in one of my searches that cutting them was not suggested. Is that true?

[silver-e34]

the proper way to do it is replace all 4 pads as sets and either replace the rotors if they are below spec thickness or have them turned at a machine shop but never install new pads without new rotors or at least turning you old ones , this is to prevent your brakes from squeeling and many other funny noises,when you remove your old pads you will see the rotors are very shiny were the pad makes contact with it and probably has a lip, that needs to be removed and the surface should be a little rough not shiny to avoid noises,however the dealer and some shops dont want to turn rotors they just wanna replace them since its faster and easier for them but more expensive for the customer

[Zeuk in Oz]

I do have a rather irritating shimmy under braking which suggests a warped rotor. I was thinking of getting them cut since there is hardly any lip on them. But read in one of my searches that cutting them was not suggested. Is that true?

This shimmy under braking could also be your thrust arms - at what speeds does it occur ?

[genphreak]

There are good reasons on these cars not to turn the rotors... but some get away with it. However they are not that much oversize in the first place so replacement is not a bad idea oftentimes.

The reason that makes me invariably replace the rotors is that they are exceedingly cheap when you consider the cost of doing wasting half a set of pads on some scored ones and/or paying (and waiting) to have your current rotors turned. Brakes are a dirty job, so they are best done properly each time AFAIAC. Also, due to the sensitivity of the e34 front end to shimmy, its really worth avoding anything that might make one have to troubleshoot shakes or esoteric wobbles once a brake job is complete.

But some don't mind messing around with them; I guess if I tracked my car I'd probably not be replacing everything each time...

I just like her to work the way she's designed to once she's all buttoned up.

[pundit]

From looking at my rotors after nearly one set of pads and 40,000kms I'd say that they are already undersize. At least a 2mm lip each side... so machining is out.