On my Cupra R ST ABT I was starting to get the occasional faint squeal from the front brakes, so pulled one of the front pads. The thickness of the friction material was down to 6mm, and the pins were just starting to show. The original discs though slightly lipped, don't seem to be marked up much. So I was thinking about perhaps getting them skimmed on the car, and fitting new original pads. Mainly because the car is still under warranty. Any opinions about if it's worth getting the discs skimmed, and the cheapest place to buy the pads? I've never paid anything like £260 for pads in the past.
Your pads have around 10mm of friction material when new.
Its best to change your pads at 3>mm
If yours are around 6mm I would say they are around/just over 50% worn. Are they wearing evenly? Sometimes they car wear at different rates to best to check all 4 for equal wear.
What's your disc thickness?
Not the lip - the actual worn friction surface thickness - you can measure this using a digital caliper and some spacers (coins work fine), then subtract the spacer/coin thickness.
New your discs are 32mm, minimum thickness is 30.4mm
Personally I'm not a fan of on car brake disc turning.
Modern discs are machined to very high tolerances (less than 10microns thickness variation!) and on car 'lathes' are relying on your own wheel bearing for running accuracy and stability!
The only specification I can find (they normally don't say what runout & DTV tolerance you can expect which again is a red flag!) was <20 microns. Double the requirement!
Not good enough for a modern high performance car! Probably ok for a Transit or a Landrover!
