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  1. #1
    Join Date
    Aug 2010

    Rear brakes not getting pressure?

    I have my Wilwood proportioning valve turned all the way in to get max line pressure to my rear brakes, but I can't seem to be able to get them to lock up. Granted, I have BP30 pads in my Aerolite fronts and BP10 in the FNSL rears. I switched out the 30's I had in the rear because I was getting a weird harmonic vibration sound when rolling to a stop, or moving forward very slowly. The sound went away after the bp10's went in, I can't seem to be able to get the rears to lock up before the fronts on pavement. I know the front pads are much more aggressive, but I thought I could adjust for that with my proportioning valve. I thought the combination would give me the feel I wanted for the street without the increased wear on the rears between track days. Thoughts?

    1969 Firebird Project
    1967 Frirebird 400 convertible
    2013 Boss 302

  2. #2
    Join Date
    Apr 2011
    The prop valve can't increase pressure so the first course of action would be to remove it.

  3. #3
    Join Date
    Oct 2014
    DFW, Texas
    Country Flag: United States
    Bleeder pressure gauges aren't very expensive, I used it to check my Wilwood setup. May be worth trying.
    1972 Plymouth 'Cuda - Not LS-swapped, 5.7L Hemi [MS3 Gold Box], T56 Magnum 6-speed - 'Cuda Build Page
    1976 Dodge D100 - Warlock
    2016 Subaru WRX - E30 Tune

  4. #4
    Join Date
    Oct 2011
    Is it possible that you have your MC lines reversed? I believe pressure is applied to rear brakes first then front that’s why a proportioning valve is needed.