Noisy brakes - MY2002 318i

[atlau]

Folks,

Sorry to start a new thread, but I couldnt find any info on this.

Lately, I have started to notice noise from my MY2002 E46 318i 4D. It sounds like a "rrrrrr" noise when braking, especially hard and when going downhill. It reminds me of my Accord a few years back when it made a similar noise and I had to get the discs "machined". Is this normal? My Accord lasted 7 years and 130,000kms before I had to get them machined. My Bimmer is only on 48,000kms, I figured the discs should be quite good condition (I don't drive like a maniac, especially when it comes to braking, I brake quite softly, like a Grandma on a nice Sunday afternoon in the country) - I hate brake dust.

Anyway what else would cause this? Recently I bought this brush of http://www.eclipsedetailing.com.au/ (Actually the product is http://www.eclipsedetailing.com.au/Products.html?code=WireSpokeBrush&image=1

this is to scrub my alloys, and I only use light meguires gold class wash when I wash my wheels, always in the cold... Is there anything else that could be happening here??
Thanks folks...

http://www.cyon.com.au/atl

[atlau]

one more question, if it is discs that need machining, is it covered under warranty?
I have another 5 months of warranty to go.

[Staszek]

They dont usually machine the rotors on BMW, pay $20 more and get new rotors. You can get OEM rotors from a few places pretty cheap. I bought Balo's for the rear at $38 a rotor and I believe the fronts cost me $45 or something like that each.

[DZeckhausen]

Lately, I have started to notice noise from my MY2002 E46 318i 4D. It sounds like a "rrrrrr" noise when braking, especially hard and when going downhill. It reminds me of my Accord a few years back when it made a similar noise and I had to get the discs "machined". Is this normal? My Accord lasted 7 years and 130,000kms before I had to get them machined. My Bimmer is only on 48,000kms, I figured the discs should be quite good condition (I don't drive like a maniac, especially when it comes to braking, I brake quite softly, like a Grandma on a nice Sunday afternoon in the country) - I hate brake dust.I would say the odds are good that your brakes are done and in need of replacement. 48,000kms (approx 30,000 miles) is not outside the bounds of reason for a 318i sedan to have gone through its brakes.

Keep in mind the 318i has the smallest brakes of any E46 model. Compare your 11.2" front/10.8" rear brakes to the 11.8" front/11.6" rear brakes of the 325i and the even larger 12.8" front/12.6" rear brakes of the 330i. As the brakes get smaller, the rotor and pad temperatures climb higher for any given stop. Heat is the enemy of brakes and accelerates wear.

To determine if you need new rotors, measure the remaining thickness. Your front rotors started out at 22mm thick and should be discarded when they reach 20.4mm thickness. The rear rotors started out at 19mm thick and should be discarded when they reach 17.4mm thickness. As a rule of thumb, BMW allows 1.6mm of total rotor wear. Other comapnies make heavier rotors with thicker friction plates, so they allow more wear and subsequently last longer. Mercedes, for example, allows 2.4mm of rotor wear. On the other hand, BMW rotors are lighter and contribute to better handling.

Braking like a grandmother doesn't help rotor life. That simply allows the transfer layer of pad material on the rotors to be chewed away and the predominant mode of braking to be abrasive rather than adherent. (Adherent is when molecular bonds are formed, then torn apart, between the pads and the pad transfer layer on the rotors.) What you need to do is install new pads and rotors, then bed them in properly. See: http://www.zeckhausen.com/bedding_in_brakes.htm. Then make sure to brake normally and, if you ever hear any symptoms of your rotors becoming unbedded (squealing under light pedal pressure) then bed them again.

If you hate brake dust, braking lightly is not the answer. You can turn to a local company, Bendix-Mintex (http://www.bendix.com.au/_corporate.asp), and buy a set of their Axxis Deluxe Plus brake pads, which produce almost no dust. They may be sold under the a different brand name in your country. Here in the USA, they are sold under the REPCO, PBR, and Axxis brands.

[Artslinger]

Dave Zeckhausen,

As usual... excellent information. :thumbup:

[swchang]

Dave, I have a squeak at light pressure (usually it appears while, as I'm coming to a stop, I gently ease off the brakes). Occasionally it occurs when I go in reverse. The squeaking gets worse when it's cold, and sometimes it disappears for a few days, but it has been quite persistent for about 10 months now, if not longer. Do you think I need to re-bed my brakes, or do you think something else is involved? I've taken it to one dealership, which said nothing was wrong and they couldn't reproduce it, but I don't know that I trust them to have even looked at the brakes at all. They did, however, say that everything was within proper operational spec.

BTW, do you have info on the 330i brake pad and rotor "new" and "worn out" measurements on your site anywhere?

Thanks for the help. I plan to visit you one day to get my CDV taken care of (the same dealership claims I don't have one, and while I haven't checked underneath myself yet, I really don't believe them).

[DZeckhausen]

Dave, I have a squeak at light pressure (usually it appears while, as I'm coming to a stop, I gently ease off the brakes). Occasionally it occurs when I go in reverse. The squeaking gets worse when it's cold, and sometimes it disappears for a few days, but it has been quite persistent for about 10 months now, if not longer. Do you think I need to re-bed my brakes, or do you think something else is involved? I've taken it to one dealership, which said nothing was wrong and they couldn't reproduce it, but I don't know that I trust them to have even looked at the brakes at all. They did, however, say that everything was within proper operational spec.In this case, I'll agree with the dealership. You have classic symptoms of unbedded rotors. A good bedding session, once the weather warms up a bit, should cure your sqeaking.BTW, do you have info on the 330i brake pad and rotor "new" and "worn out" measurements on your site anywhere?Don't have it on my site, but I do have it in my head. :) The 330i front rotors are 25mm when new and the rear are 22mm. Thus, the discard thickness specs for your car are 23.4mm and 20.4mm respectively.Thanks for the help. I plan to visit you one day to get my CDV taken care of (the same dealership claims I don't have one, and while I haven't checked underneath myself yet, I really don't believe them).Did they actually look? It should be there, staring them right in the face! Amazing. :confused:

[swchang]

In this case, I'll agree with the dealership. You have classic symptoms of unbedded rotors. A good bedding session, once the weather warms up a bit, should cure your sqeaking.Don't have it on my site, but I do have it in my head. :) The 330i front rotors are 25mm when new and the rear are 22mm. Thus, the discard thickness specs for your car are 23.4mm and 20.4mm respectively.Did they actually look? It should be there, staring them right in the face! Amazing. :confused:

Dave, you're the best. Thanks a ton. BTW, why not just rebed them now? Why wait for warmer weather?

Yeah, dunno about the CDV. Dunno about anything a lot of dealerships do (or don't do) nowadays, to be honest... Anyway, will check sometime and if I have it, which I bet I do, will be giving you a call. :)

[DZeckhausen]

Dave, you're the best. Thanks a ton. BTW, why not just rebed them now? Why wait for warmer weather? The key to bedding is to get your brakes hot enough to start transferring a layer of pad material onto the rotor surfaces. If it's only 9 degrees outside, the rotors cool off too quickly between runs and it's much harder to get a good bedding to take place. It's much easier when the temperature is 40 degrees or higher.

[andy_thomas]

I would say the odds are good that your brakes are done and in need of replacement. 48,000kms (approx 30,000 miles) is not outside the bounds of reason for a 318i sedan to have gone through its brakes.

Keep in mind the 318i has the smallest brakes of any E46 model. Compare your 11.2" front/10.8" rear brakes to the 11.8" front/11.6" rear brakes of the 325i and the even larger 12.8" front/12.6" rear brakes of the 330i. As the brakes get smaller, the rotor and pad temperatures climb higher for any given stop. Heat is the enemy of brakes and accelerates wear.

IIRC Australian-market cars are sold with an increased payload configuration, because of the Aussie propensity to tow stuff everywhere. The 318i and 320i have the slightly bigger 300mm/294mm 325i brakes (or, 11.8"/11.6" as you say). In turn, the 325i's "payload increase" uses 330i brakes; Oz-market 325s duly come with 17" wheels as standard, since 16"s do not fit. Hidden-option freaks can boost their odds of getting a free brake upgrade by asking for "S100A - Payload Increase" come order time, and hoping the dealer does not question it (just say you are going to do a lot of towing, for example). Mine didn't :).

Either way, I agree that ~30k miles is not an unreasonable service life for 318i front discs and pads, particularly in warmer climes.

[atlau]

Thanks guys,

My gawd, there's so much to learn about brakes!!! I haven't the faintest clue!! Do you mean Brake rotars is the actual disc that the brake pads rub against?

Sorry I am just a clueless guy, who knows nothing. Unfortunately BMW in this market dont have such a strong "cult following". Even in Singaproe they have their own forums (www.bmw-sg.com) which is fantastic...

Thanks so much for your opinions guys. I am getting my car oil serviced 2 weeks time (5000kms to go before next oil, but I thought just do it) so I'll ask them.

PS: Not covered under warranty right?? :)

PPS: They changed the brake PADs at 22000kms, that's different to rotars??

Thanks!!!!!!!!

[JonathanIT]

Or you could just do what my Mom recommended: I was driving her once recently and a car pulled up next to us with really screeching brakes. She remarked in all seriousness "Ooh, his brakes are really squeeking. He needs to get them oiled."

--J.

[andy_thomas]

Thanks guys,

My gawd, there's so much to learn about brakes!!! I haven't the faintest clue!! Do you mean Brake rotars is the actual disc that the brake pads rub against?

Brake rotors (US English) = Brake discs (British English). I think in Australia they use "discs".

PPS: They changed the brake PADs at 22000kms, that's different to rotars??

Yup. If, at 48,000km, you are due for a second set of pads as well as new discs, your discs are lasting for as long as two sets of pads. This is quite normal for BMWs (in other cars, you may go through several sets of pads before requiring new discs).

[Artslinger]

Or you could just do what my Mom recommended: I was driving her once recently and a car pulled up next to us with really screeching brakes. She remarked in all seriousness "Ooh, his brakes are really squeeking. He needs to get them oiled."

--J.


:rofl:

[atlau]

Thanks heaps Andy, Yes I know what discs are. Wow, so I need to change all 4?? Is that gonna cost me an arm and leg?? 4 PADs at 22000kms cost me already $800!! (plus it was inspection 1)

MY GOD - How come I only learned that you need to change the discs ever 2 pads?? I just learned discs cost $1200 for a set of 4!?!?!?!?!?!?!?
:cry:

plus pads... say $600
:cry: :cry: :cry:

PLUS oil inspection at stupid BMW service prices $500
:cry: :cry: :cry: :cry: :cry:

I can hear the salesman at the HONDA dealer laughing after I rejected him years ago on the Accord.......

Oh well, it's still an awesome drive though. Thanks so much guys for all the information :)


Brake rotors (US English) = Brake discs (British English). I think in Australia they use "discs".

Yup. If, at 48,000km, you are due for a second set of pads as well as new discs, your discs are lasting for as long as two sets of pads. This is quite normal for BMWs (in other cars, you may go through several sets of pads before requiring new discs).