Hella 355122861 Brake Rotor 325mm 6x112 Solid Disc

The Hella 355122861 is a solid brake rotor, or a brake disc if you learned the trade on European cars. It's a one-piece casting with no cooling vanes between the faces, 325mm across and 14mm thick. That solid, thinner profile is typical of a rear rotor, where braking loads are lighter and you don't need the extra mass of a vented disc. It bolts to a 6 x 112 wheel pattern and rides on a 67mm hub bore.

Hella casts these from gray cast iron, the same material the factory disc used, because it sheds heat evenly and machines to a clean, flat surface. The zinc coating is the part you notice first. It keeps the hat, the edges, and the areas the pads don't touch from flashing over with surface rust the week after you install it. Bare cast iron looks rough through an open wheel within a few rainy days. The friction faces still wear bright where the pads sweep, and that's normal, but the rest of the disc stays clean and corrosion-resistant a lot longer.

Solid discs like this one are the right call for rear-axle duty. The rear brakes on most cars do maybe a third of the stopping work, so a vented disc back there is overkill. A solid rotor is lighter, there's less to warp, and it holds up fine to the loads it actually sees. This isn't a cost-cut, it's the correct part for the job.

Fitment comes down to the numbers. 325mm diameter, 54mm overall height, 14mm thickness, 67mm center bore, and a 6 x 112 bolt circle. Those all have to match what came off the car. The cleanest way to confirm you've got the right disc is the Hella part number, 355122861. Cross it against your vehicle before you order, because a rotor that's a few millimeters off in diameter or bore won't seat right and won't clear the caliper. If you're not sure, most parts lookups will confirm whether 355122861 fits your year, make, and model in a couple of clicks.

Do the axle in pairs. Always. A fresh rotor on one side and a worn one on the other pulls the car under braking and wears the pads unevenly. And when the rotors come off, put fresh pads on with them. Fitting used pads to a clean rotor drags the old glaze across the new surface and you never get a proper bed-in. New rotor, new pads, every time.

Installation is straightforward if you're set up for brake work. Knock the old rotor off, wire-brush the hub face down to bright metal, and check that it's flat. Any rust or crud trapped between the hub and the rotor hat shows up as runout, and you'll feel runout as a pulse through the pedal at speed. Wipe the braking surfaces with brake cleaner before the pads go on so nothing contaminates the bed-in.

One more thing on the coating. The zinc finish isn't only for looks, though clean discs behind open wheels do look sharp. It slows corrosion on the vane and hat areas, which matters if the car sits for stretches or lives somewhere with road salt in winter. A rusted-up rotor hat can seize to the hub and turn a ten-minute pad swap into a fight with a dead-blow hammer down the road. Starting with a coated disc keeps that from setting in.

So when do you actually need a new one? When the old rotor's scored deep enough to catch a fingernail, when it's worn below the minimum thickness stamped on the hat, or when you've got a pulsing pedal that fresh pads won't fix. Any of those and it's time. Hella has supplied braking components to European carmakers for decades, and the 355122861 is built to that same fit-and-forget standard. It's a single disc, so order two if you're doing both sides. Honest part, fair price, and it'll outlast a bargain rotor that rusts through in a season.