It seems odd that you would need both front and rear brakes after only 42000
miles (which works out to about 70 km, does it not?) In any case, the proper
ratio is typically two sets of front brake pads to a set of rear brake pads.
Rotors typicallly last me for two sets of pads. So, at 42k miles, you should
need front pads only. Then at 85k-ish miles you will need front pads and
rotors and rear pads. then at 130k-ish miles you will need front pads again,
then at 170k-ish you should be prepared for front and rear pads and rotors.
Of course, all of this has lots of room for variables, but since you have
managed to only go 45k miles in 9 years, slightly under 9k miles per year,
my guess is that the variables are not going to come into play.
Discs and rotors are the same thing, by the way. I'm, frankly, a bit shocked
that you need front brakes at this point, and I'd be very surprised to find
that you need rear brakes. The front pads being worn out is probably okay,
but I think I get more miles on mine than that. Having said that, brake wear
is a function of stopping, and I drive many miles on the freeway withoug
touching the brake pedal, so my mileage is going to be better than yours. My
guess is that you drive around town almost exclusively, so you would use
your brakes more than I use mine. Your speeds would be lower, but your brake
application would be more frequent. In any case, you should not be needing
rear pads at this point, and certainly not rear rotors. You could need front
brakes, but I'd expect the front rotors to still have another 40k+ miles of
service left in them.
Having said all of that, you can estimate the price of rotors to be $50
each, and pads at $50 per axle set. Those prices are USD, and the actual
prices will vary a bit from there, but not too much. (I bought a complete
set of pads and rotors for my car on eBay for under $200, but then had to
pay another $40 for machine work to make them true and straight.)
I an in the UK and I have a 1999 316i (E46) with 42,000 miles on the
clock. I have been told that I need to replace brake pads and discs
front and rear. Is this usal for an 8 year old car given the low
millage?. The cheapest quote I've had is about £390 (dealer price
about £500). Is this reasonable?.
Thanks for any info.