Mercedes-Benz A-Class Brake Discs: Specs, Fitment & Wear Symptoms
A genuinely distinctive finding: a persistent vibration under braking, unresolved by replacing discs, was ultimately traced to a stuck caliper piston, not the disc itself — a G-clamp couldn't even push it back in.
Illustration for editorial purposes
Opens live listings in a new tab.
OEM Part Number: A247421041207
| Front discs, W177 | Mercedes-Benz OEM: A247421041207 — vented, sold as a pair |
|---|---|
| Front brake pad wear sensor, W177 | Mercedes-Benz OEM: A1695401617 |
| Front brake pads, W177 | Mercedes-Benz OEM: A0004205103 |
Mercedes-Benz A-Class Brake Discs: The Part That Pads Depend On
On the Mercedes-Benz A-Class, wear on one of this pair accelerates wear on the other, so a pad change booked as routine maintenance often turns up discs that have quietly deteriorated alongside them.
Mercedes-Benz A-Class Brake Discs: What They Do
Brake discs provide the surface the brake pads clamp against to slow the car, converting momentum into heat through friction. Larger, sportier trims of the A-Class typically use bigger discs than standard versions to handle the additional heat generated by more aggressive braking.
Opens live listings in a new tab.
A Genuinely Distinctive, Honest Finding Worth Knowing — Mercedes-Benz A-Class Brake Discs
If a persistent vibration under braking hasn't been resolved by replacing discs, this is genuinely worth knowing: one documented case saw exactly this kind of vibration ultimately traced to a stuck caliper piston rather than the disc itself, with the piston seized solid enough that a G-clamp couldn't push it back in during a routine pad change. Replacing just the caliper resolved the issue entirely, worth knowing that corrosion on caliper pistons has also been noted as a related cause on a similar car, with the problem expected to genuinely return once new pads wear down and push the piston further out, worth having the caliper pistons specifically checked for free movement if a vibration persists despite fresh discs and pads.
It's also genuinely worth knowing a useful, cost-free fix worth trying first: braking firmly from around 60mph five or six times in succession generates enough heat to deglaze the disc and pad contact faces, often curing a vibration caused by corrosion or uneven pad transfer without needing to replace any parts.
Mercedes-Benz A-Class Brake Discs: Wear Symptoms, DIY Difficulty & Aftermarket Advice
These are the same regardless of make or model — see our full Brake Discs Guide for warning signs to watch for, confirming fitment against your VIN, and choosing a reliable aftermarket disc.
More Mercedes-Benz Brake Discs
The same part, covered across other Mercedes-Benz models.