Braking power not as good as it should be on 308?

Discussion in 'Technical Q&A' started by 308GTS, Jan 14, 2004.

  1. 308GTS

    308GTS Formula 3

    Dec 27, 2001
    Ok, my brakes just don't seem to stop as good as they should. This is more of a sensitivity issue than the pedal travels low. I replaced the pads and it helped but I am thinking it maybe vacuum related. I cleaned the check valve out with brake clean but that didn't make a difference. I am going to get a vacuum reading from the plenum but I am not sure of what it should be. Would a missing cylinder make it have less boost/assist/vacuum from the plenum? Any info would be appreciated.
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  3. atlantaman

    atlantaman Formula 3

    Mar 31, 2002
    Roswell, Georgia
    Full Name:
    A-make sure that you installed the check valve correctly, not backwards.

    B- get a vacuum hand pump and put it into the motor end of the tube--pump it up a little and see if it holds pressure--if not it is a hose problem or the brake booster is damaged.

    C-308 brakes stink anyway--get them rebuilt or replace them with an upgrade kit.
  4. pma1010

    pma1010 F1 Rookie

    Jul 21, 2002
    Full Name:
    Brake booster hose is notorious for leaking on 308s.

    I don't know the plumbing on a FI car. On the carb'd cars the hose comes off one runner (#4 or #5 as far as I recall) and if that cylinder is misfiring, you'll get poor vacuum and a soggy pedal/little assist. If you've recently replaced pads, did you give the system a quick bleed?
  5. donaldh2o

    donaldh2o Karting

    Nov 10, 2003
    Irvine CA
    Full Name:
    In addition to checking and replacing the air booster hose, change the brake fluid.

    I just put all new pads and changed the fluid on my '76 308 and the brakes are terriific. It takes about 2 quarts of brake fluid using the MityVac pump to get a complete fluid change. I used Castrol LMA brake fluid because it has a slower rate of moisture absorption than most off the shelf fluids.

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