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A seized rear-left caliper announces itself quickly: the car drifts left under braking, the inner pad wears down to the backing plate, and the pedal starts to feel long. If you run a 1998-2001 Audi A4 or a 1998-2004 Audi A6, the Rear Left Brake Caliper 1Pc (19B2109) is built as a direct replacement for that corner.

This guide covers the specs, the fitment list, real replacement cost data, and the installation checklist in order. Every number below comes from the product data and the published industry research behind it, so you can size up both the part and the job in one read.

What the 19B2109 Actually Does

The rear left caliper is the clamp at the heart of your braking system. It converts hydraulic pressure into mechanical force, squeezing the pads against the rotor to create the friction that slows or stops the car. When the piston sticks or the seal leaks, every other component in the system works harder and wears faster.

The 19B2109 is a single-piston caliper assembly designed for the rear left position. It arrives as a complete unit with the mounting bracket included, so you are not sourcing a second part halfway through the job or reusing hardware that has already lived through years of heat cycles.

Build quality matters on a part that sits next to road salt and brake heat. This one carries a premium chrome-plated finish for corrosion resistance, a steel piston for long service life, and manufacturing that meets or exceeds OEM specifications — the reason it holds up across weather conditions instead of flaking in a single season.

Fitment: Does It Match Your Car?

Fitment comes first. Match your model and year against this application list before you order:

• Audi A4: 1998-2001 models, both the 1.8L L4 and 2.8L V6 engines
• Audi A6: 1998-2004 models
• Volkswagen Passat: 1998-2005 models, as a cross-compatible application

If your car falls inside those ranges, the caliper bolts into the rear left corner as a direct fit. For the exact match to your specific build, review the fitment data on the 19B2109 product page before you order.

Technical Specifications

Here is the full spec sheet in one place, so you can cross-check it against the part you are removing:

The port sizes are the detail people forget. The M10X1 bleeder and M12X1 inlet match the factory thread specifications, so your existing hydraulic line and bleed screw thread straight in without adapters or re-plumbing.

What Rear Caliper Replacement Really Costs

Brake work is not cheap, and it helps to know the going rates before you commit to a shop. Industry cost data breaks the job into three parts:

Two Sources, Two Different Numbers

RepairPal estimates put Audi A4 brake caliper replacement at $1,077-$1,145 including parts and labor. YourMechanic data lands at a $377 average, split as $125 for parts and $252 for labor. The spread comes down to shop rates and which brand of caliper ends up on the car.

That spread is exactly where the Koeep 19B2109 caliper earns its keep. It delivers OEM-compatible quality at a competitive price point, which can save you hundreds versus dealership parts — budget that stays in your pocket or goes toward pads, fluid, and the second caliper.

Installation Checklist and Safety Notes

With a qualified technician handling the swap, these steps should happen in order:

1. Properly bleed the brake system to remove air bubbles
2. Use new brake fluid meeting Audi specifications
3. Inspect the brake pads and rotors for wear
4. Check the brake lines for damage or leaks
5. Test full brake system function before any road use

Watch the Mileage

One more planning number: brake calipers typically last 75,000-100,000 miles, but salt, moisture, and heat cycles can kill one earlier. Past that mileage mark, inspect both rear corners — if one side is done, the other is usually not far behind.

Finish the Whole Brake Job in One Order

Most single-caliper jobs turn into two-caliper jobs once you look closely. If the right rear shows the same sticking or uneven pad wear, pair the left-side 19B2109 with the Rear Right Brake Caliper 192108, which covers the identical 1998-2001 Audi A4 and 1998-2004 Audi A6 range. Matching both sides keeps braking force even, which is the whole point.

Koeep also carries an alternate listing for the same left-hand position: the Rear Left Brake Caliper 192109, covering the same A4 and A6 year ranges. If you are comparing part options side by side, it sits one click away.

Need pads, rotors, fluid, or lines to go with the caliper? The Brakes & Brake Parts collection holds the full catalog, so you can build the complete job from one place. And if you also run a newer A6, the carbon fiber console upgrade guide for the 2005-11 Audi A6 interior is a cheap way to freshen the cabin while the wheels are off.

Need a Quote or Fitment Help?

Not sure the 19B2109 matches your exact build? Send your vehicle details through the request for quote page and the team will match the part to your car before you spend a cent.

Prefer a direct line? Email support@koeep.com or message +86 181 3883 8291 on WhatsApp for a fast answer on stock, shipping, or bulk orders.

View the 19B2109 Caliper and Order

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