3-Series (E46, E90)Chat relating to the BMW 3-Series from 1999 to Current. Models include: BMW 316i, BMW 318i, BMW 318Ci, BMW 320i, BMW 323i, BMW 325i, BMW 330i, BMW 328 Ci, BMW 328i, BMW 325i/xi, BMW 330Ci, BMW 320d, BMW 330d, BMW 335d.
I own a 2002 325i. at about 15,000 miles, brake lining light came on. Had to replace brakes. Now it is in for it's inspection at slightly over 25,000 and we're told that the brakes need to be replaced. Is this right? Should I expect from 15,000 to 25,000 miles on a set of brakes? Wife and I aren't race drivers. Why so much brake wear? At this rate, in ten years we'll probably have more money in brake replacements than we paid for the car.
I just replaced my front pads had about 35 thousand miles on the pads. Heavy stop and go traffic in city...the fronts should have at least that much in mileage wear. rears should last much longer maybe 45 or 50 thousand before changeing. maybe one or more of your calipers are sticking used. Bmw brakes can be very expensive if you take it to the dealer. . replacing them yourself you can save maybe half price of dealer charges. If its under warrenty let them do it
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Although very technical problems require and should have the dealers attention, routine maint like brakes I suggest probably using euro specialist. "Some" dealers dealers give incentives for the intangibles like suggesting other things that need to be done when your vehicle is serviced, and brakes and rotors seem to be the main thing.
My last outing to the stealership (replaced fuel pump under warranty) involved them telling me that I had about 2mm left on my front pads. The service rep said that the light would go on in about 1-2 weeks. Almost 2 months later the light is still not on. $200 for the front and $200 for the rear doesn't sit right with me when I can get better pads for $100 for all 4, plus a $14.00 sensor. You may be asking, "Well what if the light/sensor is broke?" I am doing them in 2 weeks prior to the wife and I driving to Charlotte. Thanks for the "warning" Tom Bush.
A few facts about brakes. Asbestos is now illegal for use as brake pad material. Kevlar is now widely used as a replacement. Manufacturers are not stupid. Kevlar is no better than asbestos from a braking point of view (although that is what they will have you believe). Kevlar wears down much more quickly than asbestos. It is unlikely that a set of kevlar pad will last you more than 30,000 miles.
It is not by chance that Kevlar is more abrasive than asbestos either. These days you often need to replace rotor disks every 50,000 miles. As I said manufacturers are not stupid.
So things to keep in mind. 2mm left on your pads is actually about 1/3 of its life. The first MM wears in the first 500 miles as the pads bed in. The next 6mm are the rest of your 30,000 miles. The last 3 MM hold the sensor and rivets. Anatomy of a 1cm brake pad. The dealer will warn you at 2mm because it is likely that the brake pads will need replacing before the next service (i.e. within the next year/10,000 miles). Hey he is a business man. If he can sell you new pads when your old ones are only just over half worn it is good business.
Even when the sensor light comes on you still have about 1000 miles before the rivets start to grind. Then you really know your brakes need fixing. Best to get it fixed before then.
If you change the pads yourself, look at the old sensors. It is likely that only one sensor is activated, the others are all like new. Even the activated sensor can be reused on most cars (all it does is detect an earthing on the disk).
No, I am in Europe. I doubt the rotors are different, but we do more stop start / bumper to bumper work.
I had an E30 prior to this, and an old Honda before that. The Honda I had for 13 years and did over 100,000 miles of bumper to bumper traffic, it only ever had 3 sets of pads (one it came with) and never had new rotors (pads were still ok when I scrapped the car!). The E30 I did replace the pads but the discs had very little wear when I sold it with 50,000 on the clock.
My Stealership informed me a couple of weeks ago that all rotors and pads need replacing. The car only has 35,000 miles. I have had it independently verified that the pads have 5-7000 miles left! The Rotors do need replacing soon (easy job!) but not urgent.
Originally posted by peterkulesza@May 11 2005, 02:56 PM are you in the us?
euro cars wear out pads faster (harder rotor compounds, and different pads stock), but 25k from the front pads seems ok for a us car as well.
although i can't speak entirely for Euro cars but i'm pretty sure the brake systems are the same as US cars. and there are only 2 brake sensors they are located on the left front and the right rear pads. and you CAN'T reuse an "activated", by activated i'm assuming you mean a sensor that is telling the car that the pads is worn out. when the sensor rubs to where the light comes on it has already rubbed through a wire that telles the car that the light needs to go on. and if you have a 2mm's left on your pads and they lasted another month that should go down in the books becasue that is very rare. most of the time the sensor comes on when about 3mm of pad are left. it could be a possibility that the person that neasured the pads didn't measure it right? accidents DO happen.
and to give advice on the original problem: to replce the front pads at such short intervals there is definatly somethng wrong here. it is either a mechanical problem or a user error. which i'm not try to insult i'm just listing the possibilities. if it is a mechanical problem then it could be stuck caliper/s, or even warped or overheated rotors. and since you said that you don't drive aggresivly that much it could be the opposite, ridding the brake could definatly casue premature pad failure.
and it is best to replcae rotors and pads at the same time other wise you just end up wearing out your pads sooner than usual if the rotors are changed only. it is okay to replace pads only as long as the min. thikness of the rotors isn't too close to the actual measurement,or if the rotors are:warped,overheated, or have deep grooves in them. i just don't understand why people would be cheap when it comes to the most important system on the car, the one that keeps you alive!!!
the hydraulics and sensors are the same on all cars. however:
americans tend to complain more about brake dust and noise. therefore, the rotors are cast from a different iron alloy, softer for the us, harder for europe. this results in american rotors warping more often, and quicker rotor wear. it is then not surprising that your e30 rotors lasted lifetime.....
i suspect pad compounds are different as well, this is true for most german brands (volkswagen and benz), and used to be on e36.
it is easy to verify stealership pad story. take of the wheel, and look at the pad sitting in the caliper. if there is about 2mm of the center groove left, it is ready to be replaced.
rotors unless very thin and scored can tolerate a lot, like pmb said. even a significantly grooved rotor will be ok, if you burn in the pads correctly. that is: 10 stops, moderate brake force, from about 40mph, NEVER to a complete stop. then 10 more agggressive stops, and let cool. do the sequence once more, and you are done. also, important to brake in a straight line, not to put side loads on the rotor.
I am following this up with some useful information. I had my car serviced 3 months ago and was told 2mm rear and 2.5mm front, disk runout worn. I have since done 3000 miles and no sign of any sensor lights yet. On inspection last weekend both front and rear actually look ok to me. I will be doing the job myself when it needs doing. The stealership quoted me nearly £1000 for disks, pads, fluid and labour.
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