|Tech Article Title
FT & RR brake pads on the A6 (2.8q and 2.7t)
Having just bought a "previously-owned" 2001 Audi A6 2.7t and being a long-time Audi owner, I immediately planned to change my brake pads for something that provided me with less dust! Having performed this transplant on my previous A4 using Mintex Red Box pads and being very happy with these, I decided to use the same pads for this car. I also hooked-up with a friend who recently bought a 2000 A6 2.8q and we decided to use his spacious (and warm) garage and replace the pads on both our cars simultaneously. So, after a call to Dave at
GermanAutoParts.com (who I can heartily recommend) and a couple of day wait for UPS, we were set.
Pad Replacement: A6 2.8q
First, for the A6 2.8q, it turns out that the replacement of both the front and rear pads follows exactly the same method as the A4 pad replacement article by Dale Black (elsewhere on this site). The only exception being the presence of the pad wear sensor wires/connectors. These are attached/detached the same way as the description below for my 2.7t front pads. HOWEVER, be careful to note exactly how the wires are routed when you disconnect them as they run between caliper the brake lines a fairly convoluted manner! You'll have to wiggle the connector out from between the brakes lines when you've disconnected it to remove the old pads (and vice versa when you put the new ones in).
See the next section for additional notes when changing the rear pads.
Rear Pad Replacement: A6 2.7t
Similarly, the rear pads on my 2.7t are again exactly the same as the A4 pads and article above. In fact they seem to be the same brakes (and use the same pad order numbers).
One thing to note over and above Dave's instructions for the rear pads is that if your rear pads are well worn, the pistons will have come far enough out of the cylinders to have come off the handbrake adjustment threads. This increases the difficulty of getting the pistons back into the cylinders tremendously. You can buy the very efficient Audi tool for this from the dealer for approx $60-70, or an equivalent tool from somewhere like
HarborFreight.com for about $30-40 (item # 40732). Or you can go the cheaper (slightly more difficult) route that we used. Buy a generic rear brake tool from Sears/AutoZone etc. ($10-12). These take the form of a square block with
various-sized pins on all 6 sides along with holes for a 3/8' socket drive. They are for US cars and so require some "adjustment" with a Dremel (or similar) tool for the Audi pistons. Two pins on one face of the block are almost perfect fits for the Audi, only the pins are a little too wide to fit in the slots in our pistons. You'll need to grind the pins a little flatter on two sides (a 5 minute job). Then, insert the tool into the slots in the pistons and use a 3/8" socket drive with an extension to turn the pistons back into the cylinders (regular clockwise threads). If the pistons are out past the ends of the threads, you'll have to push & turn & turn & push until you luck out and get the pistons to engage in the threads! Once they're back in the threads they go back in pretty quickly, with only 2-3 of turns to retract fully. In other words, if you're wondering if the pistons went in a little bit or not on the last turn, the chances are they didn't!
Front Pad Replacement: A6 2.7t
Replacing the (front) pads on the HP-2 (4-pad S4, A6 2.7t, A6 4.2) brakes is very easy and quick- the most difficult part being getting the sensor wire connector apart. Please Note: my understanding is that the 2003 2.7t's do not use the HP-2 brakes any longer, so if you own a 2003 (or later) the method below probably doesn't apply!
So without further ado:
- Either by using a screwdriver as a lever or using pliers, pull the outboard ends of the pad retaining spring clip assembly out of their holes in the calipers (see "A1" & "A2" on the diagram) and then rotate the clip up 90 degrees off the pads and out of the way (see "B" arrows).
- Release the pad wear sensor wire:
- Slide the pad sensor wire from under the spring clip on the caliper (marked by blue "C2" in the diagram above). Then unwind from the connector mounting plate (a
kind of S-shaped cutout below where the connector assembly mounts, marked "C1" in the diagram below. Make sure you note how it was routed so you can replace it later!
- Gently pry up plastic 'arm' on outboard (male) side of the connector assembly to release the locating pin/tab from its hole in the pressed-steel connector mounting plate/carrier (see red "C").
- Rotate connector assembly 90 deg ("D") and it can then be slid up and out of the plate ("E"). (May take some 'teasing' & rocking to get it out).
- Now the wire is free, pry the two halves of the connector apart:
· Insert a flat tip screwdriver into the front of the car-end (female) connector (green "F" below) to raise the tab off the catch on the pad-end connector.
· With a spare finger, push back on the lever tab at the back of the car-end connector ("G") to keep the tab raised off the catch, & pry/wiggle the two connector halves apart.
- Remove the master cylinder reservoir cap and suck out some fluid with a turkey baster. Save fluid in a clean container (you'll need to replace it later).
- Using a largish C-clamp, place screw end of clamp on top lip of front inboard pad (the one with the sensor wire) and back of clamp on the back of the caliper and tighten to push the pad and piston back into the cylinder. Check that the fluid level doesn't rise too high & overflow the master cylinder reservoir. Remove more fluid with baster if necessary.
- Repeat with the rear inboard pad. You may need to alternate as I found pushing-in one cylinder tended to push out the other. If necessary, insert a piece of wood between the pad and the rotor of one pad before moving on to the other to stop this happening. Keep checking the fluid level.
- When both pads/cylinders are pushed in enough, the whole caliper assembly should slide back and forth freely. Make sure the cylinders are compressed enough to take the depth of the new pads.
- Remove the inboard pads by sliding up and out of the caliper - they should be loose and easy to remove (they may even fall down and out on their own).
- The outboard pads will be stuck to the calipers with anti-squeal adhesive and will need to be gently pried off the carrier with a flat-blade screwdriver. Be careful not to mar the carrier and especially don't touch the rotor.
- Once the outboard pads are free, they will again be easy to slide up and out of the caliper.
- Replace the pads in the reverse order in which you took them out, using anti-squeal adhesive on the back of the outboard pads.
- Make sure the sensor wire is laying in the groove in the pad backing plate before replacing the pad retaining clip (in step 12) or it may be worn and/or severed by the clip.
- Rotate the pad retaining clip back down and replace the ends of the clips in the holes (opposite of step
- Reattach the pad wear sensor wire:
- Loop the sensor wire through the caliper spring clip and connector mounting plate S-cutout as it was before you removed the old pads.
- Push the male & female sensor wire connector halves together again and make sure they 'click'.
- Slide the connector assembly down into the mounting plate with the tab arm facing toward the rear of the car at 90 degrees to the plate. When pushed all the way down and in position, rotate the connector assembly 90 degrees so the arm is pointing downwards and the tab clicks into place in the hole in the mounting plate.
- Gently press the brake pedal a few times until it tightens up. Replace any fluid you took out from the master reservoir.
- Put the wheel back on & repeat for the other side. You're done!