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Audi Front Brake Pad and Disc Replacement
 
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Pelican Technical Article:

Audi Front Brake Pad and Disc Replacement

Peter Bodensteiner

Time:

1 1/2 hours

Tab:

$100

Talent:

***

Tools:

7mm Allen wrench, brake pad retraction tool

Applicable Models:

 
Audi A4 (1997-01)
Audi A4 Quattro (1997-01)
Audi TT (2000-04)
Audi TT Quattro (2000-04)
VW Beetle (1999-02)
VW Golf (2000-02)
VW Jetta (2000-02)
VW Passat (1996-00)

Parts Required:

New brake pads

Hot Tip:

Make sure car is supported correctly on jackstands

Performance Gain:

Better braking

Complementary Modification:

Flush brake fluid

Working on brakes scares a lot of people. If you screw up your braking system, you're putting yourself and others on the road at risk.

While a little healthy fear is good when dealing with braking systems, the components and operation of modern disc brake systems are relatively straightforward. Servicing them is well within the capabilities of the beginning mechanic.

Given that brake jobs are a proven profit center for many shady repair shops, doing the job yourself can save you money and make sure the job gets done right.

Front brakes usually need attention more often than rear brakes, as they bear more of the load when stopping your car. Generally speaking, the front half of most cars is heavier than the rear, plus the transfer of the car's weight forward during braking places an even greater responsibility on the front tires and brake components. Understandably, rotors and calipers are usually bigger up front, and the pads wear out more quickly.

Changing front brake pads is a good thing to know how to do, particularly if you do any track days or performance driving and thus are likely to wear out pads and rotors more frequently.

Start by loosening the lug bolts of the wheels and then raising the front of the car in the air and supporting it with jack stands (see the Jacking Up project). Go ahead and lift the whole car if you're going to do all four corners. Then remove the wheels.

The new set of brake pads I'm installing in this project comes with this diagram that explains where the pads go on the car.
Figure 1

The new set of brake pads I'm installing in this project comes with this diagram that explains where the pads go on the car. Each rotor is squeezed by two pads, one on the outboard side and another on the inboard side. As you can see, the inner pads have a metal clip in the center and are directional--they must be installed on the correct side of the car. The diagram uses semicircles embossed on the backs of the pads to help you identify the correct pad for each location. The arrow on the back indicates the direction of the rotor's rotation. Use the semicircles and diagram as your primary means of determining the correct orientation. Then confirm the orientation by visualizing the direction of the rotors rotation. If you rely on the arrow, it's too easy to become confused. Fortunately, the outer pads are identical and can work on either side.

Here's what you see when you remove the front wheel.
Figure 2

Here's what you see when you remove the front wheel. Don't worry too much about a little rust on the surface of the rotor--this should get scrubbed off as the brakes get used.

Braking generates lots of dust as the pads wear away, and the brake components will have a good bit of this dust on them.
Figure 3

Braking generates lots of dust as the pads wear away, and the brake components will have a good bit of this dust on them. Because it's not particularly healthy to breathe in brake dust, it's a good idea to use some brake cleaner to wash as much of the dust off as you can. Actually, it's not a bad idea to wear a mask or respirator while you work on your brakes. Place a rag underneath the rotor and caliper to catch the dust and excess brake cleaner that drips off.

Use some pliers to grip the one-piece spring clip that spans the caliper.
Figure 4

Use some pliers to grip the one-piece spring clip that spans the caliper. It is held in place simply by friction and pressure, so you can wiggle it loose. Just don't bend or kink it.

I worked the clip out one end at a time.
Figure 5

I worked the clip out one end at a time. The holes in the caliper that hold the end of the clip are clearly visible.

The next step is to remove the two bolts that secure the caliper to the caliper's mounting bracket.
Figure 6

The next step is to remove the two bolts that secure the caliper to the caliper's mounting bracket. The ends of these bolts are hidden behind plastic caps to keep out moisture and dirt. This is one of the caps that has just been removed to reveal the top bolt. Just to the right is a rubber protective cap for the caliper bleed screw.

Here I'm using a screwdriver to remove the protective cap on the bottom bolt.
Figure 7

Here I'm using a screwdriver to remove the protective cap on the bottom bolt.

This is the view from the inside of the wheel well facing out.
Figure 8

This is the view from the inside of the wheel well facing out. You can clearly see the lower Allen-head bolt, which is now revealed. The bolt head visible to the right is one of two that holds the caliper mounting bracket to the suspension upright.

Use a 7mm Allen wrench to remove both upper and lower caliper bolts.
Figure 9

Use a 7mm Allen wrench to remove both upper and lower caliper bolts. There's really only about a half-inch of thread on each bolt, but they'll keep turning forever. That's because each bolt is surrounded tightly by a rubber sleeve that prevents the bolt from falling out once you've loosened it completely.

Here you can clearly see that the threads have cleared the threaded part of the caliper.
Figure 10

Here you can clearly see that the threads have cleared the threaded part of the caliper. Use a pair of pliers to gently grasp the very end of the bolt and pull it through the rubber channel. Examine the bolts and clean them. If they have excessive rusting or pitting, replace them.

Here's a good look at the lower bolt after being removed completely.
Figure 11

Here's a good look at the lower bolt after being removed completely.

Now the caliper is free, but it may not come off easily.
Figure 12

Now the caliper is free, but it may not come off easily. Use a screwdriver (or an assortment of them) to pry the caliper away from the mounting bracket so you can remove the pads.

Once you have enough clearance you can place a screwdriver between the caliper and the outer edge of the rotor to lever the caliper free.
Figure 13

Once you have enough clearance you can place a screwdriver between the caliper and the outer edge of the rotor to lever the caliper free.

And the caliper is now loose.
Figure 14

And the caliper is now loose. Note that the outer pad has stayed on the rotor while the inner pad has departed with the caliper. I've placed a box nearby to set the caliper on. Then I can let go of the caliper without straining the brake hose that runs to it--you don't want to hang the caliper from this hose and risk damaging it. You could also use wire, twine, or a zip-tie to secure the caliper to the coil spring or another solid suspension component.

Remove the outer pad--it lifts right off with a wiggle or two.
Figure 15

Remove the outer pad--it lifts right off with a wiggle or two.

Then unclip the inner pad from the caliper piston to remove it.
Figure 16

Then unclip the inner pad from the caliper piston to remove it. The clip grabs the inside of the cylindrical piston to hold the pad in place.

Those crazy Germans .
Figure 17

Those crazy Germans ... rather than use some low-tech but dependable metal tabs to scrape against the rotor and make a screeching noise when the pads wear down--like other carmakers--they figured that additional failure-prone electronics and sensors would be a better solution! Therefore, the inner pads are equipped with sensors and a wire lead that must be disconnected to remove the old pads, and reconnected with the installation of the new pad. Use a small screwdriver, inserted like so, to release disconnect the pad wiring.

Now the wiring is unclipped.
Figure 18

Now the wiring is unclipped. The pad side of the connector needs to be rotated 90 degrees in that metal mounting bracket in order to be freed.

Here's a look at the old pads and new pads, side-by-side.
Figure 19

Here's a look at the old pads and new pads, side-by-side. Compare the amount of pad material left between the face of the pad and the sensor.

As the pads wear down, the piston in the caliper extends to make sure the pads can reach the rotors.
Figure 20

As the pads wear down, the piston in the caliper extends to make sure the pads can reach the rotors. In order to make room for the new, full-thickness pads, the piston must be pushed back into the caliper. A hardware-store C-clamp grips the back of the caliper and pushes the piston back into the caliper. Before doing this, however, attach the tubing of a brake bleeder kit to the caliper's bleed screw. Use an 11mm wrench to loosen the caliper bleed screw and then push the piston back in. This way, any dirty brake fluid exits the caliper rather than being forced back up into the brake system, which could damage sensitive components. Also, it keeps the brake reservoir from overflowing, which would spill paint-eating brake fluid everywhere.

Once the caliper piston is fully retracted, clip the new pad into the piston after double-checking that you're installing the correct pad.
Figure 21

Once the caliper piston is fully retracted, clip the new pad into the piston after double-checking that you're installing the correct pad.

Thread the pad wire through the loop in the metal brake line and connect the wiring.
Figure 22

Thread the pad wire through the loop in the metal brake line and connect the wiring. Clip the connector into the metal bracket.

Turning to the outer pad, peel the protective backing from the back side of the pad.
Figure 23

Turning to the outer pad, peel the protective backing from the back side of the pad.

Place the new pad in place, snug against the rotor.
Figure 24

Place the new pad in place, snug against the rotor.

The caliper should fit easily over the new pad.
Figure 25

The caliper should fit easily over the new pad.

Line the bolt holes in the back of the caliper up with the holes in the caliper mounting bracket.
Figure 26

Line the bolt holes in the back of the caliper up with the holes in the caliper mounting bracket. Now lubricate the guide pins with some anti-seize compound or brake caliper lube and push them through the rubber sleeves, and thread them into the caliper. Use the 7mm Allen wrench to tighten them to 18 ft-lbs. Then replace the protective plastic caps over the ends of the guide pins.

Place the spring clip back into the two holes, pushing both ends fully into the holes.
Figure 27

Place the spring clip back into the two holes, pushing both ends fully into the holes. Now you're back in business. Make sure to follow the recommendations of your brake pad manufacturer when you first drive with your new pads. There may be a specific brake bedding procedure that you should follow in order to get the maximum power and longevity out of the new pads. When in doubt, make a series of relatively hard, complete stops to deposit the new pad material thoroughly on the face of the rotor.

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Comments and Suggestions:
Col Sanders Comments: Best post for Audi front brakes I've seen anywhere, thanks, Ben.
October 26, 2015
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 
Mat Comments: My 2000 A6 Quattro requires a T55 star head vs the 7mm allen head. Also, there are 2 other bolts to remove the caliper - top one is a 21mm, bottom is a 18mm.

I also discovered that I have the Lucas-Girling caliper, along with the Zimmermann Coat Z Cross-Drilled front rotors.
September 21, 2014
  Followup from the Pelican Staff: Thanks for the additional info. We appreciate it.
- Nick at Pelican Parts
 

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