TurboEverything

I have searched and searched and searched for a solid answer on brake options for the b4. I replaced the rears with b5 calipers and had no problems. I am looking for information on direct swap over brake conversions for the b4. Has anyone fitted b5 fronts on a b4? I currently have the 4 lug rotors. I replaced the master cylinder and bled all brake lines and my brakes suck *****. They work but very poorly. Any info would be appreciated on conversion swaps. Thanks!

egp320i

I have stock brakes, I run EBC Ultimax2 pads and Zimmermann x-drilled coated rotors and I can stop damn fast and I am more then satisfied.
Nothing really wrong with the Girling calipers, if they are old they might be worn out and you do need to check the two guide pins often and keep them lubed.
I have used various lubes from nickle anti to ATE plastilube and if you get a year that is about it before they get dry.

I make it my annual check when I swap winter/summer tires to check the pins and make sure they move freely.

TurboEverything

I just realized after looking at my rears that they are actually c5 calipers. I fit them without issue but could my brakes not be functioning properly because of the c5 calipers in the rear? Maybe it screws with the pressure/flow of fluid? My brakes suck right now. The car does stop but not nearly as good as I would like it to. It just doesn’t feel right. I have to put the pedal almost all the way to the floor in order to stop it. If I slam the brake pedal all the way to the floor the abs kicks in and it will skid to a stop. I verified my issue is not my brake booster.

egp320i

Well the 90 has the same rear calipers [if Q] as the A4 but without doing some research I really doubt the C5 rear brakes are designed for the 90.
Bear in mind the rear brakes only do about 20% of the braking which is why they are smaller, the fronts take the heavy lifting.

If you need to put the pedal to the floor it seems to me you need a good brake bleed with fresh fluid, that sounds like air in the system.

TurboEverything

I ended up getting the problem figured out. I still had air in my lines possibly due to a poorly performed bench bleed on the new master. I put new pads and rotors all around and the car stops on a dime now 👍🏻