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brake pedal feel

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Old Oct 21, 2014 | 12:10 AM
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Default brake pedal feel

had a question............when coming to a hard stop and downshifting using engine braking, is it normal to have the brake pedal feel like it loses pressure to where the brake pedal pushes down further towards the floor for a split second?

was wondering, does anyone get what i am describing and/or know what causes that to occur?


thanks!
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Old Oct 21, 2014 | 01:35 AM
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Yes your brake pedal will modulate when braking hard. ABS etc.....
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Old Oct 21, 2014 | 09:10 AM
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Originally Posted by LexyISF
Yes your brake pedal will modulate when braking hard. ABS etc.....
thats not really what i'm referring to though. i meant specifically during engine braking while the brake pedal is firmly pressed
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Old Oct 21, 2014 | 09:29 AM
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Originally Posted by scamsel
thats not really what i'm referring to though. i meant specifically during engine braking while the brake pedal is firmly pressed
so you're saying while firmly pressed, the brake pedal will sink down momentarily and then firm back up again?
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Old Oct 21, 2014 | 10:18 AM
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No, that should never happen in a healthy braking system. Owned 2 ISFs and never had the pedal "sink" down while downshifting when coming to a very hard stop.

Maybe you have air in your lines, maybe a brake fluid bleed/flush?


Originally Posted by scamsel
had a question............when coming to a hard stop and downshifting using engine braking, is it normal to have the brake pedal feel like it loses pressure to where the brake pedal pushes down further towards the floor for a split second?

was wondering, does anyone get what i am describing and/or know what causes that to occur?


thanks!
Reply
Old Oct 21, 2014 | 12:53 PM
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Originally Posted by itsmike177
No, that should never happen in a healthy braking system. Owned 2 ISFs and never had the pedal "sink" down while downshifting when coming to a very hard stop.

Maybe you have air in your lines, maybe a brake fluid bleed/flush?
thx mike, i guess i'll get it checked out, but just to confirm....i'm speaking about when in manual and sport mode. it doesn't do it just when applying heavy braking solely from applying the brake pedal (where the car just downshifts on its own accord).

rather, its only when manually downshift through a couple gears, inducing some engine braking (as the car kicks up the rpm's to rev match) at the same time as i am applying the brake pedal.
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Old Oct 21, 2014 | 02:30 PM
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Yes, M + sports mode, revmatching downshifting while braking hard (rpms at 5000+ when downshifting to the lower gear), pedal should not sink down in any car. Mine never did.

Originally Posted by scamsel
thx mike, i guess i'll get it checked out, but just to confirm....i'm speaking about when in manual and sport mode. it doesn't do it just when applying heavy braking solely from applying the brake pedal (where the car just downshifts on its own accord).

rather, its only when manually downshift through a couple gears, inducing some engine braking (as the car kicks up the rpm's to rev match) at the same time as i am applying the brake pedal.
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Old Oct 21, 2014 | 02:35 PM
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I would have noticed that for sure. It's never happened in my car.
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Old Oct 21, 2014 | 02:36 PM
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I have done three track days with mine and never noticed anything like that and I compression brake on almost every corner and apply the brakes harder then anyone on the streets
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Old Oct 21, 2014 | 03:45 PM
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Originally Posted by I8ABMR
I have done three track days with mine and never noticed anything like that and I compression brake on almost every corner and apply the brakes harder then anyone on the streets
What he said, but more track weekends.
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Old Oct 21, 2014 | 05:51 PM
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cool thanks again all. the 2 i was hoping would reply did, ha. i'll check it out, see if a brake fluid flush does anything
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