Hi everyone
2003 r53, replaced the drivers side rear caliper last weekend with a facelift rear caliper. After bleeding the brakes in the correct order we had a good stiff pedal. But when I started the car the pedal went to the floor, no brakes at all. When the car is off the pedal is stiff, but the brakes are barely there. Would love some insight on this, have been looking around the last few days and haven’t seen any posts with issues like this, and Facebook didn’t help at all. When I bled the brakes, manually and correctly, I didn’t have the cap off of the brake fluid tank. If you have a suggestion please let me know, would love to get brakes back lol

 

you only replaced "one" caliper?? (you should always replace them in pairs)

did you make sure that the bleeder screw was at the top of the caliper?

Did you ratchet the e-brake a number of times to get the piston in the correct spot?

Did you use a vacuum bleeder or just push the pedal with your foot (or someone else's)

Did you get the rear pads on the caliper correctly with the spring that attaches the pads?

Almost sounds like you have air in the lines

Bryan

 

The lines are all bled correctly, was getting a steady stream of fluid out each caliper. I am pretty sure either my brake booster or my master brake cylinder went bad

 

The pedal going to the floor when you start the car shows that the vacuum assist is working. You probably have air somewhere in the system. Make sure if you bleed the old way by pushing the pedal that you have a hose attached to the bleeder nipple and the other end in a jar of fluid. That way you can watch for air bubbles and you won’t suck air back into the line if you let up on the pedal before you get the bleeder tight. Make sure the brake fluid reservoir stays full. You may have to do this for a while before you get it to firm up.

 

Jack -

Read the manual...it's actually a "two step" bleed process. Read that, a "traction control" situation. Though you should not have to do the two step bleeding if you were careful and did not allow much fluid to drip out of the line, and did a "prefill" of the caliper before the installation, you did push a lot of fluid from the system, so a two step bleed will be required,

And NO, as long as the opposite side caliper is in good condition, you do NOT need to replace both calipers at the same time..! Although, putting fresh pads on both side is a VERY good idea.

Mike

 

Where is the brake fluid reservoir in an f56 2021 S? I’d like to check the level but cannot locate the reservoir cap or is this another fluid that cannot be checked by the owner like the oil.