Question on brakes

Discussion in 'Suspension, Steering, Brake & Wheel Topics' started by ULTM8Z, Dec 24, 2017.

  1. ULTM8Z

    ULTM8Z Veteran Member

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    May 19, 2000
    Los Angeles
    Basically it's a "feel" thing... how far down you push the pedal before you feel the brakes starting to grab.

    With the engine off, there's very little free play before resistance is encountered in the pedal and it feels like good hydraulic pressure is being developed when I push the pedal down.

    Who knows, maybe you'd get into my car and say "WTF are you complaining about?"... lol...

    The car doesn't have any problem stopping, so maybe it's all in my head. As I said earlier, bleeding (or rather practically flushing) the brakes seems to have resulted in a marked improvement. But I'm going to call Baer this week and see what they say.

    Given what Todd said about the "better pedal feel" of the '81 and the '81 being the quick up-take MC, I'll ask Baer about that as well and see what they say.
     
  2. badazz81z28

    badazz81z28 Veteran Member

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    May 4, 2001
    Las Vegas, NV
    "Maybe you'd get into my car and say "WTF are you complaining about?"...Lol.... From real world driving, I can say quick stops at the drag strip at 120mph to zero and quick breaking on straight away turns going 100+, don't ever feel like the brakes are not feeling like they are working.

    I drive my '14 ram and a '12 focus quite a bit and I would think if my camaro had a braking deficiency, it would be very noticeable to me after driving those cars. I don't however. Could it be your after a manual braking set-up feel with now power brakes? Have you tried ditching the stock Prop Valve and go adjustable? There could be a internal problem with the one you have. Also, I had a bad booster back in 2008 I had to push the pedal hard to stop the car.
     
  3. ULTM8Z

    ULTM8Z Veteran Member

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    I don't really have to push the pedal hard to stop the car. At idle, again, much less so after having re-bled the brakes (it actually feels "normal" at idle now).

    Before the Baer set up, it was factory front discs with Stainless Steel brakes rear disc conversion. Different MC, different booster, different prop valve... but still power brakes.

    The Baer set up was pretty much a clean sheet of paper.

    Any rate, the whole thing now is how soon the brakes grab vs how far the pedal is depressed. Once the brakes engage, everything feels pretty normal.
     
  4. jamieg285

    jamieg285 Veteran Member

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    Jul 15, 2004
    Luton, England
    I'm late to the party, but no-one has mentioned MC bore size yet.

    I've got a Baer set of around the same vintage that I've yet to fit. The stock MC on disc/drum is 1 1/8" and on disc/disc was smaller at 1". The advice I've been given, both by Baer and others, that was for these particular brakes, based on the C4 caliper, you need an even smaller one - a 15/16" one from the C4 for best pedal feel. I got mine from CPP - part# M-C1516-S
     
  5. ULTM8Z

    ULTM8Z Veteran Member

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    Just got off the phone with Baer. Sounds like the 15/16" bore size could be the way to go. Though he said the C4 Vettes had a 7/8" bore? That seems very small.
     
    Last edited: Jan 5, 2018
  6. ULTM8Z

    ULTM8Z Veteran Member

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    Interesting... I found this bit of info...

    Based on the 3.5 pedal ratio I currently have, maybe I need the .875 bore size... it'd get to factory 88-91 Corvette specification...

    '85-'87

    MC Bore .875"
    Wheel cylinder bore 2.1" front 1.6" rear
    Pedal arc ratio 3.5 to 1
    Line pressure with 100 lb on pedal 1250 front 800 rear

    '88-'91

    MC Bore .87"
    Wheel cylinder bore 1.5" (dual) front 1.6" rear
    Pedal arc ratio 3.5 to 1
    Line pressure with 100 lb on pedal 1250 front 750 rear

    '92-'96

    MC Bore .93"
    Wheel cylinder bore 1.5" (dual) front 1.6" rear
    Pedal arc ratio 4.0 to 1
    Line pressure with 100 lb on pedal 1160 front 680 rear
     
  7. badazz81z28

    badazz81z28 Veteran Member

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    I’m pretty sure the MC I’m using is 1-1/8
     
  8. ULTM8Z

    ULTM8Z Veteran Member

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    With what calipers? It's the combination of piston sizes that matters....
     
  9. ULTM8Z

    ULTM8Z Veteran Member

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    Did a search on pro-touring.com... Looks like a mid 70s monza had a 7/8 bore...

    Raybestos # MC 39027 (L.H.) (cast iron) 7/8 bore (manual & power)
    '76-80 GM Monza • Sky Hawk • Starfire • Sunbird

    Probably will try it out
     
  10. ULTM8Z

    ULTM8Z Veteran Member

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    Los Angeles
    I think I just figured out what's going on... and the 7/8" would have made it worse.

    Doing some searching online, it looks like Baer supplied 15/16" MC bore size with their kits way back then.

    In which case, I'm actually running the 92-96 C4 Corvette MC/caliper combination, but with a smaller pedal ratio.

    Given the excessive travel I have now, a 7/8 bore size would make things worse, not better. It's a little odd since going to the 7/8 "should" get me to 88-91 spec, but maybe my booster has something to do with it as it's obviously not the same as the C4 vettes.

    So then it looks like I need to either go to a 1" or larger (not sure if there's a 1 1/16" bore size).

    Anyone know off hand what GM applications used a 1" bore?
     

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