Delay to brake pedal at high rpms | FerrariChat
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Delay to brake pedal at high rpms

Discussion in '360/430' started by P1key, Jan 31, 2023.

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  1. P1key

    P1key Karting

    Nov 9, 2022
    82
    Full Name:
    Jeff Pike
    #1 P1key, Jan 31, 2023
    As I get used to the car ('00 360), I'm starting to drive it a bit harder, and recently I've felt a few times as I come off the throttle and go to press the brake pedal, particularly at high rpms, there's a delay when pressing the pedal before I can actually brake (!)

    It's like the brake pedal doesnt get the assist from the vacuum straight away, there's a delay of maybe half a second, and during that time although I'm pressing the pedal its rock hard and I get very little braking. This only happens at high rpms, but typically this would be at the end of a straight bit of road when I brake for a corner, so hardly ideal.

    Could this be the inline check valves? I've read that they can stick open/closed, although that doesnt describe exactly what I'm feeling. Can they be 'lazy' and take a short while to operate, or do they either work or not work and I should be looking somewhere else?
     
  2. 360trev

    360trev F1 Rookie
    Project Master

    Oct 29, 2005
    4,327
    Gibraltar
    Full Name:
    360trev
    #2 360trev, Feb 5, 2023
    There was a very long time a recall part on 99 and 00 MY brake hose which could cause this issue. I'd assume the vast majority would have had them replaced by now.

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    If that's not the issue you need to go and replace the fluid (brake fluid is hydroscopic, that is it absorbs water over time which is compressible) so if your fluid is past its sell by date it's likely you just need a full flush of the system and bleed.

    If you still have issues next step is to verify pad condition and brake piston seals, if your pistons are siezing in the bore of the caliper they can require more pressure to release. All is pretty straightforward to verify.

    Good luck

    Sent from my CPH2145 using Tapatalk
     
  3. mike32

    mike32 F1 Veteran

    May 13, 2016
    5,927
    Isle of man- uk
    #3 mike32, Feb 5, 2023
    This is what causes the brake caliper pistons to seize on a 430. Only 3 out of 6 on my front calipers were free to work.
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  4. fatbillybob

    fatbillybob Two Time F1 World Champ
    Consultant Owner

    Aug 10, 2002
    28,709
    socal
    #4 fatbillybob, Feb 5, 2023
    Wow...that looks like lack of maintenance maybe coupled with low quality part. Ferrari parts are nit the best but I have seen 70s Toyota junkyard pistons seized in bores come out looking better than that.
     
  5. mike32

    mike32 F1 Veteran

    May 13, 2016
    5,927
    Isle of man- uk
    #5 mike32, Feb 5, 2023
    Its sure not bad maintainence, the quality is another matter. Chrome onto alloy. Interesting point is the corrosion is in way of where the dust seal sits, no corrosion where the oil seal sits.
    Some seized solid and took some getting out of the caliper which was undamaged.
     
  6. P1key

    P1key Karting

    Nov 9, 2022
    82
    Full Name:
    Jeff Pike
    #6 P1key, Feb 6, 2023
    The car was given a major service and new rear discs and pads before I bought it (October), front pads and discs look fine. The brakes work totally fine in all aspects of driving, so I dont think its the fluid or the pistons in the calipers.

    I didnt realise that check valve thing was actually a recall. I will physically inspect this later to se if that little extra valve is included.
     
  7. mike32

    mike32 F1 Veteran

    May 13, 2016
    5,927
    Isle of man- uk
    #7 mike32, Feb 6, 2023
    You can hang the caliper, remove the pads and fit a wood block between the pistons, press the brakes to see if the pistons move. Make the wood block thick enough so the pistons can be seen moving but not pop out.
    I only found my seized pistons by accident when a front wheel was dragging slightly
     

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