I have changed brake pads and rotors on my LR3 until we got rid of it at 90K miles in 2011, at which point we purchased a new LR4 in May 2011. Today, we have 31K miles on the LR4 and the pads and rotors still look good.
One of the big dealer "rackets" over the last decade has been the story that customers need to replace pads & rotors at the same time. In short, pads and rotors are built to function within specific tolerances. All you need to do is measure their thicknesses at various points of life. This "story" is price gouging, pure and simple - not only on parts, but also on labor...
I have two tools that save my wallet: 1) a flashlight, and 2) a micrometer. I use the flashlight to look at my brake pad thickness with the wheels on, checking every month or so while the car is parked in the driveway, You can see the outside pad thickness quite easily, though seeing the inner pads is a bit tougher. I usually wear old clothes and crawl under the car with the flashlight to look, or sometimes put the car on a lift to get closer.
In my experience, brake pads will wear out
much faster than rotors. On my LR3, I changed rotors every second brake pad change in the front, and in 90k miles NEVER changed my rear rotors. Due to the weight of these car, front pads and rotors wear out quicker. Definitley pay attention to those front pads!
When the pads start to look visually thin, I order OEM pads and a new pad sensor from British Pacific or British Atlantic, and then pull out my hyraulic lift and raise the car. I take the wheels off, and look closely at the pads and sometimes even use the micrometer to check thickness. Usually, you can eyeball it and know that pads need changing. I sometimes use the micrometer to measure the exact thickness of the rotors. If in spec, you are good to go.
Min PAD thickness = 3mm
Rotor specification for the LR3:
Front Disc LR3 Rotor - Vented
Diameter, Height, Thickness, Min-Thickness
mm = 317, 62.2, 30, 27
Rear Disc LR3 Rotor - Vented
Diameter, Height, Thickness, Min-Thickness
mm = 325, 59.6, 20, 17
This allows for a 3mm reduction in each rotor..
I am not certain of the specs for the LR4, but I think they are the same.
I'll post some DIY pics when I need to change my pads... With the LR3, it was a very easy process (less than 30 minutes for two wheels)
-B
