How to Diagnose Failing GTI/Golf R Brake Calipers

Performance driving takes a toll on your brakes. Many Golf GTIs and Rs on the road are equipped with Volkswagen’s state-of-the-art Performance Package. The components in the Performance Package are designed to handle a lot of heat and abuse.

Brake calipers often last 80,000-100,000 miles, and perhaps longer. But they still wear out eventually. Calipers are subject to extreme heat – especially during performance driving. They are also exposed to moisture, dirt, and road salt in snowy states.

So when you start noticing a decrease in the effectiveness of your braking system, it’s worth checking out the calipers.

Symptoms of Failing Brake Calipers

When your calipers start to go bad, you’ll notice symptoms like:

  • Brake fluid leakage
  • Thudding sounds when you hit the brakes
  • Vehicle pulling to the left or right
  • Decreased overall braking performance

If you suspect a problem with your calipers, we strongly urge you to check out these parts as soon as possible. Your car's brake calipers are the heart of it's brake system. Also, if a caliper piston sticks, it can rapidly ruin a rotor, leading to additional repair expense.

Luckily, confirming that the issue lies in your calipers isn’t hard. It’s a diagnostic process that takes less than an hour and requires a few basic tools.

Inspecting the Calipers

Used VW caliper

Calipers are very simple devices. When you push on the brake pedal, you are pushing brake fluid towards the brake pistons. The pistons slide in the caliper to put pressure on the brake pads. The caliper rides on slide pins, which allow the caliper to move very slightly side to side to accommodate break wear. When calipers fail, it is usually one of a few things:

  1. The piston seal has failed. The caliper can't put as much force on the rotor as it should. Fluid will leak from the caliper.
  2. The piston is stuck in the "in" position, and can't put enough force on the rotor.
  3. The piston is stuck in the "out" position, and can't fully retract. This causes the pads to constantly drag on the rotor.
  4. The slide pins have become corroded, restricting the motion of the caliper.
  5. Sometimes calipers will develop cracks in the arms that connect the caliper to the caliper mount. This rarely happens, but it is an important safety concern.

When you inspect the calipers, you are looking for one of the above failures. To inspect:

  1. Safely lift your GTI or R.
  2. Take all four wheels off.
  3. Visually inspect the calipers for any cracks. Look at the area near where the caliper attaches to the caliper mount.
    1. If you spot even a small crack on a caliper or mount, then it needs to be replaced as soon as possible.
  4. Look for any brake fluid leakage. Brake fluid is thinner than oil, so this can be hard to spot. A tell tale sign is brake dust stuck to the caliper near the piston.
  5. Inspect the brake pads for uneven wear.
    1. If any one set of pads is more worn than the other three sets, that caliper's piston is probably sticking.
    2. If any caliper has one pad wearing more than the other in the set, the slide pins are probably corroded.
  6. With the car in neutral, you should be able to spin each brake rotor. (The rotors on the drive axle will take more force to move.) All should move and produce a slight dragging sound.
  7. Have a friend push and release the brake pedal while you observe each caliper’s operation.
    1. To diagnose piston issues:
      1. Attempt to turn each rotor when the brakes are applied. If the rotor moves at all, then the caliper isn’t gripping as tightly as it should.
        1. If you can move a rotor, observe the brake pads on that brake to confirm that they are not moving.
    2. To diagnose slide pin issues:
      1. Note how smooth each caliper’s motion is when the brakes are applied and released. All four calipers should operate in the same manner.
      2. When the brake pedal is released, both pads on a brake should only lightly rest on the rotor. If one pad has more friction than the other, the slide pins could need replacement.

What if the Calipers are Bad?

Change caliperImage credit: stoppedsnoring

A replacement is in order. Order an OEM replacement part at wholesale pricing from RealVolkswagenParts.com. Then follow a reliable tutorial to replace the caliper(s).

Got any questions that weren’t answered in this article? Feel free to contact us.