I recently had my car, a 2006 VW Jetta 2,0 Comfortline with 134 000 km on the odometer, serviced at the agents.
Everything checked out fine, but according to the service adviser, the front brake pads as well as discs had seen better days. The rear pads were slightly better but the dealer said they would be due for replacement at the next service, or even earlier. The quote for the replacements was sky high and I decided to replace only the pads at a specialist dealer. Did I make a mistake not to replace the front discs with the pads, and is it safe to drive like this? The last thing I want is a brake disc failing. I am a calm and careful driver and brake hard only when necessary.
GEROME HAUPT, Caledon
Answer: We agree that workshops often replace discs too early. Obviously, they need to be replaced when they are warped (highlighted by a shudder under braking), but replacement due to wear is a grey area. In the old days, disc skimming was the norm but lately labour and the machining equipment have become so expensive that replacing discs is actually cheaper. A new train of thought is that, since asbestos has been banned from pads, the replacement materials are actually more abrasive and reduce the lifespan of the discs compared with asbestos pads. The sure way to know when discs have to be replaced is when they are worn to below the minimum thickness specified by the manufacturer. This will also lead to a pronounced ridge on the outside of the disc. The rule of thumb for replacement is when the ridge exceeds about 2 mm, but check the manufacturer specifications for the minimum disc thickness for your car.