My current brake pads are almost gone and I bought a new set. Now the rotors are perfectly fine but I have to change the pads. My question is: do I have to machine the rotors before I put the new pads on or can I just put the new pads on and machine the rotors if/when they warp?
You can replace just the pads providing the rotors are smooth and have no lip. If they do, it's worth replacing the rotors as well (I don't believe in machining rotors)
that depends entirely on the rotors.
OEM rotors should be replaced with every set of pads on the focus.
when i first started working on this car i machine the rotors but within a month or 2 they would all come back with warped rotors and 90% left on the pads... started using the Brembo blank rotors and you CAN get one machining out of them but that depends on how fast you go through your pads.
if you are easy on the brakes you should have no problem getting one cut out of the Brembos. if you are hard on the brakes then you should replace the rotors.
also, if you replace JUST the pads, be sure to be very easy on the brakes untill they bad in. this can be as long as 200kms or longer if there are grooves in the rotors. if you go out and tromp on it, you wont have brakes like normal!
also know that new pads on unmachined rotors will squeak and make noise.
Well the reason I ask and I should have included it in my original post is because I have brembo blanks and they aren't worn at all. This will be my 3rd set of pads in 5 years (104,000km). I'm gonna see what happens when I just change the rotors and drive them for a few hundred kms.
sorry for the newbie question but how do you know if your brake pads are going or gone without looking at it? i never really had a squeal to my brakes before, but now they squeal everytime i hit the brakes, but only if i press them normally to lightly, if i hit it hard there is no sound at all, also i've had my car for almost 2 years now and been to 1 track day, i feel i use the brakes "sorta" hard during street driving, but they still seem to stop really well.