Brakes slow to bite

Discussion in 'Troubleshooting & Diagnosis' started by TCinthe6, Sep 17, 2019.

  1. TCinthe6

    TCinthe6 Veteran Member

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    I ripped out the old manual brakes that were in my '73 and upgraded everything.

    Went with a Baer setup in the front and rear, along with their master cylinder, prop valve, and mated that to a dual 9 inch booster.

    After I installed everything, I bled the system 3 times, and was having issues with the pedal coming back really slow, and coming off highway speeds, it felt like the brakes were dragging. Changed the booster on warranty, and those too issues seems to have gone away.

    But I am still experience the brakes really slow to bite, and it's much more noticeable coming down from highway speeds in a hurry to a complete stop.

    It's like nothing...a little brake...brake...brake...BITE! And then it slows down. Just not a linear feeling at all.

    Any ideas of things I could check?
     
  2. cadillac_al

    cadillac_al Veteran Member

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    It sounds like the pads need to be warmed up before they start grabbing. That must be how High performance brakes feel. I rarely use my brakes in daily driving so when I have to panic stop my brakes are always cold. That's why I always buy cheap organic pads or semi metallics for my cars. If I autocrossed I'm sure your brakes would work much better.
     
  3. 70Znut

    70Znut Veteran Member Lifetime Gold Member

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    I agree with cadillac_al ...
    When I upgraded from street pads to HP pads I got the same effect. When the pads are cold very little bite, they have to be heated up before the really go to work. If they are hp pads they are probably getting cool cruising down the highway and then heating up down the off ramp. What pads are you using?
     
  4. G72Zed

    G72Zed Veteran Member

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    Both cadillac_al and 70Znut pretty much got it nailed down.

    I would call Baer to get there recommendations based on your issue and see what they say.

    FWIW, I use 4 different style of pads pending what I am doing with the car, Street/light or heavy brake autocross/road race-HPDE events all use different pads.

    Here are a few charts for reference, everyone has their brand of pads, but it's a start.

    A6F41057-D25B-4C72-AAAD-ADCF495BFDA2.jpeg HawkPadChart_grande_c5986223-1a40-46e1-b38c-603ee665fc04_480x480.jpg
     
  5. TCinthe6

    TCinthe6 Veteran Member

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    Interesting.

    I called Baer to see what kind of pads they said they provide with their system. They said it was a street compound, so there's no need to get heat into them.

    Gave them my feedback on what I'm experiencing...let's see what they say. I'd be willing to try some different pads to see if there's a change. If that doesn't work, I might even go as far as trying the DSE master/booster setup to see if that makes a difference.

    Gotta say, kinda disappointed that I'm $5K into this brand new brake setup, and my 2015 F150 with 200K km has better brake feel.
     
  6. CorkyE

    CorkyE Veteran Member Lifetime Gold Member

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    Don't start changing pads or anything else until you hear from Baer. That doesn't sound to me like a pad issue. I'm not using their system, but with what you've spent, they should provide some guiding tech support. IMHO
     
  7. G72Zed

    G72Zed Veteran Member

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    I like using/testing with a brake line pressure gauge, pinpoints to possible issues of blockage or MC that are to large/small for the combo, also helps seeing front to rear bias pressures.

    Silly question, did you change from the upper "manual" hole to the lower "power" hole on the brake pedal arm?
     
  8. TCinthe6

    TCinthe6 Veteran Member

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    I'm using Baer's MC that they recommended for a power assisted setup to their calipers/rotor combo. The MC has a 1 inch bore. Might go the route you suggested just to see what sort of pressure I am getting on all 4 corners, and what's coming out of the master.

    As for the upper vs lower hole...yea...using the lower one. If I was using the upper one, I think I would have even more leverage than what I have now. But the issue of the brakes biting late would still exist.
     
  9. G72Zed

    G72Zed Veteran Member

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    Let us know what you find out if you get that pressure gauge. Hope you find the issue.
     
  10. TCinthe6

    TCinthe6 Veteran Member

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    I think I am on the right path after spending the weekend messing around with some hard stops.

    I noticed the first thing while I was cleaning the car. There was a lot more brake dust on the front wheels than the rear wheels. I know this is typical, but there was almost no dust on the rears and the fronts had a thick layer caked on. Additionally, the front rotors had a different feeling to the touch vs the rears.

    I gave the proportioning valve a few turns for some more rear wheel bias and took it out for a drive. Felt better. I took a read of the rotor temperatures just to see how they were warming up. Front were definitely hotter, but the rears were warming up too.

    I'm going to guess that the "late bite" feeling was the front brakes engaging first, followed by the rears a few seconds later with insufficient bias.

    Fronts need to lock up just before the rears, so I'll get out to a parking lot and try to dial it in a bit more. Hopefully it's as simple as that.
     

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