# check brake wear?



## XKxRome0ox (Mar 3, 2003)

i have about 650miles left on my free maintenance... 

i had oil change done around 34,800 miles.. and my service rep told me i had ... something like 25% left on my front pads... and that i probably wouldn't make it before the maintenance ends... 

i have been a little harder on my brakes than normal... hoping to wear them out... but.. i wanted to know if there's any way i can check how much brake pad i have left without going to the dealer... can i just LOOK at the pad and figure it out ?

if i'm not close to getting a new pad before 36,000 miles (i have about 35,350miles right now)
then i'm gonna ease up on the brakes and use them as long as i can... but if i'm getting close, i'll ride them til they scrape my rotors so i can save myself some $$ on the brake replacement


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## The HACK (Dec 19, 2001)

OEM brake pads are 11mm thick. Dealers will NOT change the pads unless they're less than 3 mm thick I believe.

If you have an open spoke style wheel with a lot of gaps between the spokes, you CAN rotate the wheels a little to see the outside pad and get an idea of how much pad material is left. BMW also sells a pad thickness measuring tool that you stick into this little hole on the caliper to measure how much is still left without having to remove the wheels.

Do keep in mind, the inside pad, since it's attached to the piston itself, wears out quicker than the outside pad. If your outside pad is down to about 3mm, chances are your inside pad is a little bit lower.

Complain to your dealer that your brakes squeel and they'll replace the pads for free...That's what I did with my wife's car, at 30K+ miles I just told them the brakes squeal like pigs and they changed out the pads, no questions asked.


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## 2001E46 (Nov 12, 2002)

The HACK said:


> *BMW also sells a pad thickness measuring tool that you stick into this little hole on the caliper to measure how much is still left without having to remove the wheels.*


Any idea how much this tools costs, and what the part number is?


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## XKxRome0ox (Mar 3, 2003)

i need help ...

i want to wear down my brake pads... without ruining anything else on my car... and with minimal tire wear

what should i do?
i've been taking local streets instead of the freeway so that i can use the brakes a lot more than i normally do
and i've even tried riding my brake slightly on the freeway
not sure if that's a smart move or not

so... if you know how to purposefully wear the brakes down, please help


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## DZeckhausen (Mar 11, 2003)

XKxRome0ox said:


> *i need help ...
> 
> i want to wear down my brake pads... without ruining anything else on my car... and with minimal tire wear
> 
> ...


 I'm not sure this is the best thing to do, especially in traffic. By riding your brakes on the highway, you will heat them up. If you heat them up enough, you will boil some of the fluid in your brake calipers. Why should you care about this? Because once you've boiled the fluid, the gas bubbles are compressible. Next time you step on the brakes, you could be in for a surprise as the pedal sinks to the floor or at least has significantly more travel than you expected. This could be enough to cause you to rear end another car.

When your pads are nearly worn out, the problem is even more likely to occur because the pad acts as an insulator between the hot rotor and the brake fluid. As the pad wears down, more heat is transferred to the brake fluid. It has to go through the pad backing plate and the caliper piston, but both of these items transfer heat much more readily than pad material.

If you really want to wear down your brakes without causing other problems, you should get on the highway and execute a series of slowdowns from about 80 to 30 mph. Allow enough time between each slowdown for the brakes to cool off. If you feel the brakes starting to fade, then you aren't allowing enough cool-down time.

Be really careful when you do this! I've found that when I try to bed-in new pads and rotors on the street, other drivers become curious, frightened, or agresssive. Speeding up and slowing down is also likely to attract the attention of the authorities, so make sure your radar detector is good and don't do this if you've had anything to drink.

Rotors and pads are NOT that expensive if you buy them someplace other than a BMW dealer. Zimmerman, ATE, and Balo are good aftermarket brands. I would suggest you give up on this approach for getting your rotors and pads replaced.


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## XKxRome0ox (Mar 3, 2003)

thanks for the heads up.
i will stop riding my brakes

i've been doing the short spurts ... accelerate then brake hard from signal to signal

well i have 210 miles left on the maintenance... and i have an appointment on friday for BMW service 
so if i don't make it by then, i'll give up
and look into buying brake pads and rotors elsewhere

thanks~!


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## XKxRome0ox (Mar 3, 2003)

wahahahahahahhahaha

i made it~~~!~ :thumbup:

i have 118 miles left on my free maintenance... took it to Nick Alexander BMW this morning... the service rep told me i needed to replace everything, front AND rear pads and rotors

before he checked the brakes he offered the maintenance extension to 50k miles for $700
now that i got my free brakes, i don't need to upgrade

that made my day


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## DZeckhausen (Mar 11, 2003)

XKxRome0ox said:


> *wahahahahahahhahaha
> 
> i made it~~~!~ :thumbup:
> 
> ...


 Hey! Congratulations!!


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## TGray5 (Jan 22, 2002)

Excellent...so they replaced the pads before the indicator light came on? I may need to change dealers. Did you get new rotors too? If not, keep an eye on them, they could be very close to tolerance and BMW wouldn't replace them.:thumbdwn:


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## Nick325xiT 5spd (Dec 24, 2001)

StahlGrauM3 said:


> *Excellent...so they replaced the pads before the indicator light came on? I may need to change dealers. Did you get new rotors too? If not, keep an eye on them, they could be very close to tolerance and BMW wouldn't replace them.:thumbdwn: *


I was rather under the impression that the policy was to replace rotors with every pad change... :dunno:


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## XKxRome0ox (Mar 3, 2003)

they changed pads AND rotors
because i was at the wear limit on everything

i'm so happy
saved myself a good $600-800 
kinda makes me feel better about upgrading my digital camera AGAIN
(my 3rd upgrade in less than a year)
:dunno:


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## TGray5 (Jan 22, 2002)

Nick325xiT 5spd said:


> *I was rather under the impression that the policy was to replace rotors with every pad change... :dunno: *


Nope, my Brake pad light was just on and they only replaced the rear pads....they said the rear rotors were 'within spec'. BMWNA is pretty strict and actually requires the old parts to be shipped to them for verification before they will reimburse the dealer. If the parts are still within spec. the dealer eats the cost.


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## XKxRome0ox (Mar 3, 2003)

now a question about brake fluid flush...

BMW recommends at least once every 2 years...
i'm coming up on 2 years...

i got a coupon from Pacific BMW .. $88.88+tax for brake fluid flush
good deal ?
:dunno: 

or can i put in better aftermarket brake fluids and get it done at a shop for less?
i don't have any tools to do it myself... and even if i did have the tools, i probably wouldn't touch my car until my warranty was over


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## nate (Dec 24, 2001)

Nick325xiT 5spd said:


> *I was rather under the impression that the policy was to replace rotors with every pad change... :dunno: *


 Only if they are warped and/or too thin...


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## DZeckhausen (Mar 11, 2003)

XKxRome0ox said:


> *now a question about brake fluid flush...
> 
> BMW recommends at least once every 2 years...
> i'm coming up on 2 years...
> ...


 BMW recommends the fluid be flushed every two years starting from the date of manufacture, not the in-service date. So you're probably more in need of new brake fluid than you thought.

The question is, after this much time, are you boiling your brake fluid? Do you get a sinking pedal after any hard stops? Do you plan to take your car to the track? If the answer is no, then you would be wasting your money to buy ATE Super Blue (or TYP 200) or Motul 600 fluid. You simply don't need the extra headroom in boiling point.

The most important thing is to get the old fluid out so that the moisture in the system doesn't lead to corrosion. There are no special "lubricating" properties or any other magical properties of these high performance brake fluids, so if boiling is not already a problem, upgrading to high performance fluid gains you nothing. Just get some fresh stuff in there soon.

Brake fluid has a wet and a dry boiling point, usually separated by almost 150 degrees. Over a 2 year period, the fluid slowly absorbs moisture and the boiling point drops steadily from the dry point to the wet point. By just replacing your old fluid with fresh stock fluid, you will still be raising the boiling point by that much.


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## XKxRome0ox (Mar 3, 2003)

thanks for the info
my car's a 5/01 production... acquired in 7/01
so i'm still within the 2 year period

but i was just wondering about the cost of replacing with aftermarket fluids at an independent shop
instead of at the dealer


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## DZeckhausen (Mar 11, 2003)

XKxRome0ox said:


> *thanks for the info
> my car's a 5/01 production... acquired in 7/01
> so i'm still within the 2 year period
> 
> ...


 $88 is not a bad price for a 4-wheel brake bleed plus hydraulic clutch bleed. I doubt you can do better. Plus, Pacific BMW will have the computer attachments that will cause your ABS pumps to cycle during the pressure bleed, assuring you get fresh fluid throughout the system.

Make sure it's understood that they are including the bleeding of the hydraulic clutch which uses the same reservoir as the brakes.


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## XKxRome0ox (Mar 3, 2003)

... i don't have a clutch on my car...  


i guess i'll schedule my brake fluid flush at pacific bmw after my vegas trip this weekend
get a free carwash after the long drive
:thumbup:


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## Kaz (Dec 21, 2001)

Just a quick thing to add.

Note: I'm not an expert; just relaying information I've seen in lots of other places:

Higher-performance (i.e. higher boiling point) fluids _generally_ tend to sacrifice hygroscopicity(??) to achieve their results. As such, with a few notable exceptions (Castrol SRF), fluids with extremely high wet/dry boiling points such as Motul 600 should be changed more often than once every 2 years. This is a non-issue for racers since they change their fluids pretty much all the time. In this respect, it seems Ate 200/superblue appears to do quite well in that it's safe for 2 years in street use yet is suitable for racing.

This is still an area I'm reading up on, but so far it looks like Ate 200 is a tough product to beat, especially at ten bucks a quart.


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## DZeckhausen (Mar 11, 2003)

Kaz said:


> *Just a quick thing to add.
> 
> Note: I'm not an expert; just relaying information I've seen in lots of other places:
> 
> ...


 I agree with you about ATE TYP 200 being a good bang for the buck brake fluid for most people. I like it better than the ATE Super Blue Racing because that stuff tends to stain the inside of the reservoir blue after a few years, at which point it becomes hard to see the level through the sides.

It's scary that much of what you find on the Internet is copied and pasted from something I casually wrote many years ago! Since that time, Motul 600 has been reformulated and has a higher dry boiling point (593 F) and a longer in-service life to the point where I would not be afraid to use it for a daily driver. It's overkill for a daily driver, but it no longer has any disadvantages other than price.

A quick search on brake fluids yielded:

http://www.v8sho.com/SHO/BrakeFluid.htm
http://www.shotimes.com/SHO3brakefluid.html
http://www.nsxhelp.com/Brakes/BrakeFluids.htm
http://www.gti-vr6.net/library/wheels_tires_brakes/brake_fluid_comparo.html
http://www.scuderiaciriani.com/rx7/brakes.html

I've been trying to chase down the webmasters at those various sites so I could provide them with updated information. I don't know about you, but I find it a little scary! I mean, who is this Zeckhausen guy anyway?


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## Kaz (Dec 21, 2001)

DZeckhausen said:


> *
> It's scary that much of what you find on the Internet is copied and pasted from something I casually wrote many years ago! Since that time, Motul 600 has been reformulated and has a higher dry boiling point (593 F) and a longer in-service life to the point where I would not be afraid to use it for a daily driver. It's overkill for a daily driver, but it no longer has any disadvantages other than price.
> *


I agree. There seems to essentially be 2 articles/tables that get copied everywhere. The easy way I tell them apart is that one has a larger table with less common fluids on it, and the other doesn't.

Because of this I've tried to find more information (a lot from manufacturer information, some of which is actually dated(!!)) to have some worthwhile information.

Basically I have been concentrating on information pertaining to any possible benefits to using a DOT5.1 (no, not 5!) rated fluid like Motul 5.1 over a "super 4" class product like Ate 200.


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## The HACK (Dec 19, 2001)

You will need to completely drain the system before you can use the DOT 5 fluid, since DOT 5 fluid and DOT 4 fluid CAN NOT mix in the system or you'll get hydraulic failure. At least that's what I heard.


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## Kaz (Dec 21, 2001)

The HACK said:


> *You will need to completely drain the system before you can use the DOT 5 fluid, since DOT 5 fluid and DOT 4 fluid CAN NOT mix in the system or you'll get hydraulic failure. At least that's what I heard. *


Nonono, re-read my post. I said 5.1, not 5. :slap:

DOT5 appears to have ALL SORTS of issues. I don't know why it exists at all, really, except to refill Harleys, which supposedly comes factory with them.


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