FRONT BRAKE CALIPERS ON A 1976 308 | FerrariChat
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FRONT BRAKE CALIPERS ON A 1976 308

Discussion in '308/328' started by steve meltzer, Dec 7, 2024.

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  1. steve meltzer

    steve meltzer Formula 3

    Sep 18, 2004
    1,221
    with Enzo 8995
    #1 steve meltzer, Dec 7, 2024
    My car was pulling to the right upon even modest braking. In taking the calipers apart, I saw something that I've not seen in previous brake rebuilds. All 4 pistons have an area that encompasses 3/4 of the circumference and sits proud to the remaining 1/4. Thus giving an uneven, or seemingly uneven, application to its pad. I've enclosed a couple of pictures to explain the situation in less than 1000 words. Apparently, this is correct since it was on both sides and, my 308 shop manual seems to indicate this in its diagram of the brake system. I can't think of any reasonable explanation for this, but there surely must be one. Can anyone provide it? Thanks, Steve.
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  2. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,839
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #2 Steve Magnusson, Dec 7, 2024
    Last edited: Dec 7, 2024
    I can guess that it is to shift the center of pressure towards the trailing side of the pad (relative to the disc motion) and a little towards to OD to get more even pad wear (and not overwear the leading side of the pad):
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    Or could be for noise/vibration -- just a thought...
     
  3. steve meltzer

    steve meltzer Formula 3

    Sep 18, 2004
    1,221
    with Enzo 8995
    #3 steve meltzer, Dec 8, 2024
    thanx Steve, steve
     
  4. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    37,114
    Cowboy Capitol of the World
    Full Name:
    Brian Crall
    #4 Rifledriver, Dec 8, 2024
    Correct. Its an anti squeel method. In some cases it due to design of pad backing plate.
    The pictured tool isnt needed. The end of the raised portion ends at 6 oclock when 6 oclock is defined as the axis of the wheel.
     
  5. steve meltzer

    steve meltzer Formula 3

    Sep 18, 2004
    1,221
    with Enzo 8995
    #5 steve meltzer, Dec 8, 2024
    Brian, Thanx again. stevve
     
  6. paul01

    paul01 Karting

    Jul 31, 2011
    104
    #6 paul01, Dec 10, 2024
  7. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    37,114
    Cowboy Capitol of the World
    Full Name:
    Brian Crall
    #7 Rifledriver, Dec 10, 2024
    Sort of pointless I think. Those tabs will not position an improperly installed piston and once installed the pistons do not rotate on their own.
     
  8. paul01

    paul01 Karting

    Jul 31, 2011
    104
    #8 paul01, Dec 10, 2024
    If you "improperly installed piston" you cant put it in parallel position. So you see your mistake, but it will not correct it.
    "do not rotate on their own" -> the reason i do not install it.
     
  9. 3px19

    3px19 Karting

    Aug 29, 2006
    218
    Full Name:
    Calvin crouch
    #9 3px19, Dec 10, 2024
    What method did you use to get the pistons out. I just split mine today. My 79 has the same type of pistons as yours.
     
  10. steve meltzer

    steve meltzer Formula 3

    Sep 18, 2004
    1,221
    with Enzo 8995
    #10 steve meltzer, Dec 10, 2024
    Use compressed air through the fluid channel AND COVER THE STUCK PISTON WITH A TOWEL, because once it is free, it can fly out at tremendous speed...very dangerous at that moment. Once I got mine completely disassembled, and cleaned, I decided it was a bigger effort than I should have put out. So, I cut my losses and sent them to PMB Performance in Utah. They'll be done right, finished correctly and I can use the time for something else I want to do. i did all four calipers on two Daytonas, so I have nothing to prove. Remember that the "through" bolts are NOT Torx head, but Ribe style....didn't want to deal with that either. steve
     
  11. paul01

    paul01 Karting

    Jul 31, 2011
    104
    #11 paul01, Dec 11, 2024
    I use a piece of wood. Here few years ago on a 308 of a friend:
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    And then air...or

    I connect the caliper for one Minute again to the brake line and use the brake pedal.

    or if a piston totaly stuck:

    I do not remove the caliper. Only the brake pads (not easy in this case). And then a small piece of wood or sheet metal between the pistons an the rotor.

    So i do not split the caliper if not neccessary. I split only the rear ones.
     

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