Announcement

Collapse
No announcement yet.

Sloppy Brake Pedal

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Sloppy Brake Pedal

    2000 NB, no ABS. This started very suddenly today while at AMP, went from a firm pedal to a soft one in the space of a session, and progressively got worse despite a quick bleed in the parking lot during lunch.
    Symptoms: Very, very soft brake pedal. The first 2/3rds of pedal travel do absolutely nothing, then it kinda grabs in the last 3rd.
    System is COMPLETELY bled. I even enlisted another person to pump the pedal while I cracked the bleeders- bled all four, starting from RR, moving to RL, FR, and lastly FL.
    NO ABS
    Redline DOT4 fluid.
    Rear is completely stock lines, calipers, rotors. Front has Wilwood calipers, stainless lines, new rotors.
    With the car off, the pedal is stiff and firm. Once I turn the car on and the assist kicks in it sinks right to the floor.
    Not leaking any fluid, level in the reservoir remains the same.
    The only two things I can possibly think of are:
    A: Redline fluid is junk(doubt it).
    B: Stock rubber lines in the rear are "ballooning" and bye bye all my pressure(also doubt it but have not observed the lines while under pressure).

    I have a willwood proportioning valve that I did have set "neutral", stock pressure to the rear. I cranked it all the way in to "cut off" the rear brakes and see if the pad stiffens up or remains soft... hopefully that will help pinpoint the issue?

    Any other ideas?
    '00 Black NB, Track/Street car.
    It seems like the most powerful weapon in the universe is speed. Move something fast enough and it will obliterate anything

  • #2
    Pedal OK with the car off, bad while running = booster or vacuum leak.
    David Luney - Suwanee GA
    [email protected]
    04 RX-8, 10 Black MS3, 08 Red MS3, 06 550i, 05 325i 92 Spec Miata and a parts car or two.

    Comment


    • #3
      Really? Interesting... Had not considered that. Just a leak anywhere in general, or a leak in the booster?
      '00 Black NB, Track/Street car.
      It seems like the most powerful weapon in the universe is speed. Move something fast enough and it will obliterate anything

      Comment


      • #4
        Could be either. If you have a vacuum leak you might see a high idle or CEL as well. Other potential is a failed one-way valve. I don't recall if they are inline on NBs like they are on NAs.
        David Luney - Suwanee GA
        [email protected]
        04 RX-8, 10 Black MS3, 08 Red MS3, 06 550i, 05 325i 92 Spec Miata and a parts car or two.

        Comment


        • #5
          My idle is normal and I can't hear/feel any vacuum leaks with the engine running.

          The part number is the same between the NA's and the NB1's, so I'll assume they also have that check valve.
          David, I know you gotta have those two IM to brake booster lines laying around, wana sell them to me for $10? Cheaper test then a new master :D
          '00 Black NB, Track/Street car.
          It seems like the most powerful weapon in the universe is speed. Move something fast enough and it will obliterate anything

          Comment


          • #6
            Sure. I'm around. Drop me an email to confirm.
            David Luney - Suwanee GA
            [email protected]
            04 RX-8, 10 Black MS3, 08 Red MS3, 06 550i, 05 325i 92 Spec Miata and a parts car or two.

            Comment


            • #7
              No dice on the valve. Additionally, when I pulled the line off the booster, I had to break a pretty firm seal and let air in, the booster was still holding vacuum, so I think that can also rule out a bad booster.
              '00 Black NB, Track/Street car.
              It seems like the most powerful weapon in the universe is speed. Move something fast enough and it will obliterate anything

              Comment

              Working...
              X