Brake DiscMachining

Brake disc machining at PRO SERVICE (Batumi, Airport Highway 212): we take a thin layer off the braking surface to remove runout, grooves and the edge lip. Price from … GEL per axle, takes 1-2 hours. We measure thickness first: if the disc would end up below minimum, we will suggest disc replacement instead.

When machining makes sense

• The pedal or steering wheel pulsates under braking, but the disc is still thick — typical after overheating on long descents.
• An uneven braking surface, light grooves, a lip at the edge.
• Corrosion patches after a long stand that did not wear off with braking.
• You are fitting new pads on discs with enough thickness left and want even contact.

When machining will not help

• Thickness is already near the minimum ("MIN TH" on the disc or the manufacturer's data): after cutting, the disc would be below spec.
• Cracks, blue heat spots, deep rust pitting.
• A thin solid disc on an inexpensive model: machining can cost about as much as a new disc.
• The runout comes not from the disc but from a dirty or bent hub or a worn wheel bearing — machining hides the symptom for a while, then it returns.

How we do it

1. Measure thickness with a micrometer and runout with a dial gauge before any work.
2. Check the hub and wheel bearing to find where the runout comes from.
3. Machine the disc (on the car or off it, depending on equipment) to a flat surface, removing as little metal as possible.
4. Measure thickness and runout again.
5. Reassemble, usually with new pads, lubricate the caliper slide pins, test drive.

Worth knowing

A machined disc is thinner, so it holds less heat and warms up faster under hard braking. Machining restores a flat surface, not thickness: the same disc usually cannot be machined a second time, so the next step is replacement.

Where runout comes from

Most often from overheating: a long descent on the brakes, then a hard stop and holding the pedal while standing. The hot disc cools unevenly and pad material imprints on the surface. Engine braking on descents helps, as does tightening wheel bolts with a torque wrench to the manufacturer's torque rather than with an impact gun.

Prices