Tsinsta93
09-01-2020, 10:57 AM
Some of you might be like me, and on the hunt for a budget friendly upgrade whenever something breaks on your B7. Working and studying from home for the past 6 months has meant that my A4 barely was driven, and unfortunately I had a rear caliper freeze shut. I was fairly certain it was a problem with the lever on the caliper for the parking brake, as it didn't seem to be retracting as far as the other side, but the cables operated fine. I disassembled the brakes and lubricated things, but no dice. I should have tried bleeding it, but instead blamed the 15 year old caliper and decided it was time to replace it. I also wanted to do pads and rotors since I had heated the old pads and rotors pretty badly driving home with the brake sticking. They looked okay once I got things apart so this expense could have been saved, but I didn't want any funny behavior from the components if they were compromised.
After perusing the available replacement options, I found that S4 brakes are similar in cost (aside from giving up a core fee). Cobbling together information from several sources, I found the benefits of this upgrade included a larger diameter rotor and a rotor that was vented instead of single disc. The Caliper piston is similar in size, and the A4 and S4 share the same master cylinder, so no problems there. With this established I decided to order a Powerstop caliper (bracket included), rotor, and pad combination via Amazon. I originally found the package on Rock Auto, but had a CC deal that gave an additional 5% back on an Amazon purchase so I went that route. The order plus taxes and shipping came out to just shy of $400. When things arrived they looked good.
194708194709
I'm not an expert on powdercoat but the initial finish looked good and did not easily scratch in an inconspicuous test spot. Most hardware was included, except for the bolts that attach the caliper bracket to the hub. I reused them but you could get replacements from ECS or Audi.
It started out like any other rear brake job. See crusty old setup.
194710
Because I had recently lubed the slide pins and checked on everything, it came apart without a problem. Here's a comparison of the old and new rotor.
194711
Getting the caliper bracket off is a bit more involved. Typically people don't have to remove this, so its not included in most of the DIY's. I found the best way was to just remove the rear shock. I have ST coilovers and found that the shocks were completely dead at this point. Bit off a couple more $$$ and got some Bilstein B8 ordered to remedy this. Then dug out my impact grade Allen head sockets and found the H8 to be a pretty good fit. Tapped it in with a small sledge to make sure it was well seated, and carefully turned the bolts loose with a torque wrench. No drama here, but some people have had this strip.
194712
With the bracket off, it was time to see how the new stuff fit. I wasn't sure if I would have any issues with the A4 hub or dust shield, since they are different PN's than the S4 model. Doing a full hub swap would be a lot more involved. In this case, the bracket fit up just fine.
194713
It was definitely more difficult to slide the S4 rotor past the hub and into the caliper bracket like we all do on the a4 brakes. It helped to have the bracket still a bit loose when doing this. Not sure what it will be like down the road if I have to change pads. Once the shocks came in, I installed them and finally switched over the calipers. Be prepared to clean up some brake fluid when this happens.
194714194715
Bleeding them was a pain. I flushed quite a bit of fluid through but still had a soft pedal. Tried flushing with the car running and of course hit all 4 corners. Ultimately went back to Powerstop's website where they recommend bleeding by building up pedal pressure (car must be off for this), then opening the valve and letting the pedal drop and closing it before the pedal comes back up. 10-15 rounds of this finally got most of the air out of the system. The brakes still felt pretty soft until I went out and put some heat into them to bed them in. Now they are grabbing much better. I plan to give a more long term review once I put some miles on the set up, but wanted to share this info with anyone else looking for a street-friendly brake upgrade on a budget. So far no parking brake problems either.
After perusing the available replacement options, I found that S4 brakes are similar in cost (aside from giving up a core fee). Cobbling together information from several sources, I found the benefits of this upgrade included a larger diameter rotor and a rotor that was vented instead of single disc. The Caliper piston is similar in size, and the A4 and S4 share the same master cylinder, so no problems there. With this established I decided to order a Powerstop caliper (bracket included), rotor, and pad combination via Amazon. I originally found the package on Rock Auto, but had a CC deal that gave an additional 5% back on an Amazon purchase so I went that route. The order plus taxes and shipping came out to just shy of $400. When things arrived they looked good.
194708194709
I'm not an expert on powdercoat but the initial finish looked good and did not easily scratch in an inconspicuous test spot. Most hardware was included, except for the bolts that attach the caliper bracket to the hub. I reused them but you could get replacements from ECS or Audi.
It started out like any other rear brake job. See crusty old setup.
194710
Because I had recently lubed the slide pins and checked on everything, it came apart without a problem. Here's a comparison of the old and new rotor.
194711
Getting the caliper bracket off is a bit more involved. Typically people don't have to remove this, so its not included in most of the DIY's. I found the best way was to just remove the rear shock. I have ST coilovers and found that the shocks were completely dead at this point. Bit off a couple more $$$ and got some Bilstein B8 ordered to remedy this. Then dug out my impact grade Allen head sockets and found the H8 to be a pretty good fit. Tapped it in with a small sledge to make sure it was well seated, and carefully turned the bolts loose with a torque wrench. No drama here, but some people have had this strip.
194712
With the bracket off, it was time to see how the new stuff fit. I wasn't sure if I would have any issues with the A4 hub or dust shield, since they are different PN's than the S4 model. Doing a full hub swap would be a lot more involved. In this case, the bracket fit up just fine.
194713
It was definitely more difficult to slide the S4 rotor past the hub and into the caliper bracket like we all do on the a4 brakes. It helped to have the bracket still a bit loose when doing this. Not sure what it will be like down the road if I have to change pads. Once the shocks came in, I installed them and finally switched over the calipers. Be prepared to clean up some brake fluid when this happens.
194714194715
Bleeding them was a pain. I flushed quite a bit of fluid through but still had a soft pedal. Tried flushing with the car running and of course hit all 4 corners. Ultimately went back to Powerstop's website where they recommend bleeding by building up pedal pressure (car must be off for this), then opening the valve and letting the pedal drop and closing it before the pedal comes back up. 10-15 rounds of this finally got most of the air out of the system. The brakes still felt pretty soft until I went out and put some heat into them to bed them in. Now they are grabbing much better. I plan to give a more long term review once I put some miles on the set up, but wanted to share this info with anyone else looking for a street-friendly brake upgrade on a budget. So far no parking brake problems either.