Dodge Repair: disc brake skreech

Question
Hi Roland,
I have a 2000 Neon, 94,000 miles, never had any brake work done.  Backing out of the garage & coming to the end of my driveway, they'd screech, but then after I got going they were quiet.  A friend replaced the front brake pads and they were quiet for a couple weeks but now they're back to screeching. Was he supposed to have done something with the rotors as well?  (He didn't). Someone told me he should have turned down the rotors. I asked him and he said they don't do that anymore, they just replace them.  I don't know what's what.  What do you think is causing the screeching & what should I do?  Thank you.

Answer
Hi Andee,
Brake 'chirp' sound may be due to excess rotor runout (side to side variation as it rotates and that is to be less than .08 mm measured near the outer edge of the rotor. Or it can simply be a lack of lubrication on the brake caliper slides. So try lubing the slides(Mopar multipurpose lubricant) and see if that solves the problem. "sqeek" at low speed and light application of the brake can be due to a need for pads. If neither of those correct it:
Rotors still can be and are machined to correct various sorts of unevenness. There are 4 pages in the manual that describe the various techniques for refurbishing the rotors. There are also specifications as to the minimum acceptable thickness of the rotor which when that is approached should be the basis for replacement. Rotors generally are not high priced parts so it may be worth comparing the cost of new rotors with the additional labor involve with servicing the old rotors rather than replacing them. The minimum thickness is shown on the surface of the rotor. So check the price of new rotors, and then the cost of 'turning' the old rotors. Either way there will be some labor cost involved but if the rotors have acceptable thickness and are not badly scored it may make sense to service them. I can copy the 5 pages in the manual that discusses the details and send them to you as an attachment to an email. But you need to tell me your email address but if you do so don't use the @ symbol instead use "at" or the address will be automatically erased.
Depending upon whether your driving requires frequent or infrequent use of the brakes, about 100,000 miles might be reaching the point where the minimum thickness is approaching in which case replacement would be appropriate.
Roland