G4 Front Brake Caliper - Left

This front left brake caliper (passenger side on RHD vehicles) is a replacement ATE floating, single-piston caliper designed for VW models using the larger front brake setup with vented discs 25mm thick, and either 288mm or 312mm disc diameter (application dependent). With its 54mm piston, it delivers the hydraulic clamping force needed for heavier or higher-powered variants where a bigger disc package improves heat control and stopping performance.

If your current caliper is sticking on its sliders, the piston is seized, or the seals are leaking, you’ll typically see symptoms like the car pulling under braking, uneven pad wear, overheating, brake judder, or a soft/long pedal. Replacing the caliper restores smooth movement, even pad contact, and consistent braking feel.

What the caliper does

The brake caliper converts hydraulic pressure from the braking system into mechanical clamping force on the disc. When you press the brake pedal, brake fluid pressure acts on the caliper piston. The piston pushes the inner brake pad into the disc, and because this is a floating caliper, the body slides on guide pins to pull the outer pad in as well—so both pads grip the disc evenly.

How it works (and why “floating” matters)

A floating (sliding) caliper relies on two key movements:

1. Piston movement: The 54mm piston extends to apply the inner pad.

2. Slider movement: The caliper body moves on guide pins so the outer pad clamps with equal force.

If the guide pins seize (very common), the caliper can’t “float,” leading to one pad doing most of the work, overheating, and rapid wear—so a fresh caliper (and ideally fresh slider hardware) makes a big difference.

Key specifications

• Fitting position: Front axle left (Passenger side on RHD)

• Manufacturer restriction: ATE (must match the system on the car)

• Type: 1 piston floating caliper

• Piston diameter: 54mm

• Disc type: Vented

• For disc thickness: 25mm

• For disc diameters: 288mm or 312mm (depends on model/brake package)

Fitment overview

This caliper is listed across a wide range of VAG applications that share the larger ATE front brake package, including:

• VW Golf (approx. 11/1991–12/1997 and 08/1997–06/2006 ranges depending on model/engine)

• VW New Beetle (selected engines/years)

• VW Bora (selected engines/years)

• VW Passat B3/B4 (selected engines/years)

• VW Vento (selected engines/years)

• Plus other listed VW applications that use the same ATE setup

Important fitment warning: This caliper is specifically for 25mm thick vented discs and 288/312mm diameters. Many of the same cars also came with smaller 22mm thick 256/280mm brakes, or with TRW/Lucas calipers instead of ATE. So it’s essential to confirm disc diameter + disc thickness + caliper brand (ATE) before ordering.

Other parts commonly required (or strongly recommended)

To ensure the job goes smoothly and you don’t have to redo labour:

• Correct brake pads for ATE 54mm caliper

• Caliper carrier/bracket (some calipers are supplied without the carrier; also 288 vs 312 typically uses different carriers)

• Guide pins + rubber boots (fresh hardware prevents sticking)

• Pad fitting kit / anti-rattle springs (if applicable to the design)

• Brake hose (replace if perished, bulging, or seized unions)

• New mounting bolts (often stretch/locking type depending on model)

• Brake fluid (always bleed the system after caliper replacement)

• Brake discs (recommended to replace in axle pairs if worn/lipped/heat-spotted)

Best practice: Replace calipers in axle pairs (left + right) where possible for balanced braking.