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Thread: Braking performance, over time.

  1. #1
    Altia ER34 GTT Domestic Engineer JetspeedCamry's Avatar
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    Default Braking performance, over time.

    Just a quick question regarding a cars braking performance over time.
    I have some Bendix Ultimate pads installed. When i first put them in, the brakes felt great..very responsive and stopped quite well. Ive had them in for almost 3 years now.
    I was told that a brake pad will not degrade in its performance, the further down it gets, however, my brakes lately have been a bit spongy and the car does not feel as willing to stop as it used to.
    So my question is, will brake pad performance degrade as they wear? Or do they retain there braking performance right down to the last MM of meat?

    Thanks
    Kind Regards,
    Kurt.

    1998 ER34 ニッサン スカイラインGT- T
    RB25DET 5 Speed Manual | Blitz SE Return Flow FMIC | Greddy Profec II Spec B BC | Apexi N1 Turbo Back Exhaust

  2. #2
    Toymods Net Nazi Too Much Toyota river's Avatar
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    Default Re: Braking performance, over time.

    Hi,

    The material in the brake pads is all the same. Therefore, there should be no difference in stopping whether the pad is new or down to the last mill.

    If your brakes are feeling spongy then you may have some air in the brake lines. Air, unlike brake fluid, compresses under pressure, and this gives the spongy feel to the brakes. Air in the brake lines compromises the required non-compressibility of the brake-fluid, and therefore it is possible the calipers won't exert themselves onto the disc with the same pressure as a non-compromised system, - ergo, the car doesn't seem to stop as well.

    Air can get into the brake system by either a leak or by repeated brake use that results in the brakes getting so hot the fluid (near the calipers) boils.

    seeyuzz
    river
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  3. #3
    EVO's Are the Dark Side. Grease Monkey ae86trueno's Avatar
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    Default Re: Braking performance, over time.

    Has your brake fluid been changed in that 3 years ???

    other then fluid degredation, disk thinning or warping and possibly pad glazing the braking performance should remain constant.

    Ben.

  4. #4
    Junior Member Too Much Toyota oldcorollas's Avatar
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    Default Re: Braking performance, over time.

    it is possible to age/burn out the binder material in brakepads such that their performance does degrade with time... ie if you overheat them too many times, they work not as well..

    but spongy brakes, as others said, is less likely to be pads, and more likely to be something mechanical.
    have you been cooking them often?
    "I'm a Teaspoon, not a mechanic"
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  5. #5
    Toymods Net Nazi Too Much Toyota river's Avatar
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    Default Re: Braking performance, over time.

    Hi,

    If your disc is warped you usually feel the brake pedal vibrate as the pads run over the warp.

    seeyuzz
    river
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  6. #6
    Junior Member Automotive Encyclopaedia
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    Default Re: Braking performance, over time.

    Pads get a taper, leading edge to trailing edge -from the different heat & condition of the disk, from its initial contact to its last, and from top to bottom edge - from the different speed of the rotating disks inside radius to outside radius, just from normal usage, and added to that they get some help from those usless little POS shims/anti-squeek stuff, and the fact that everything flexes & twists - caliper, caliper bracket & axle.

    these single piston things are even worse.
    put a hand on the caliper and feel it twist & move when worked, when it's trying to get the tapered pads to conform to the hopefully parallel caliper & disk, and the perpindicular slide pins!
    It'll probably still flex when the pads are straight, but not nearly as much.

    Air is obvious, and I don't think it's worth mentioning!
    Last edited by allencr; 07-05-2006 at 04:04 AM.

  7. #7
    Altia ER34 GTT Domestic Engineer JetspeedCamry's Avatar
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    Default Re: Braking performance, over time.

    Aight thankyou for your replies!.

    As far as cooking them goes, i rarely do constant hard braking. I have hard braked them, but only to a stop, and never over and over again through a mountain run or whatever.
    The fluid has been changed once in that time, about 6 months ago. I have also new rotors too, about 1 year-1.5 years old. Rotors are still in top condition. No leaks as far as i can tell, there is no fluid external to the system and the resovoir is still topped up.
    Over the time ive done all the above things, the pads have never been changed/come out. Is it possible that somehow an air bubble has gotten into the system? How much air has to enter to be able to feel a difference?

    Thanks once again. +rep for you all
    Kind Regards,
    Kurt.

    1998 ER34 ニッサン スカイラインGT- T
    RB25DET 5 Speed Manual | Blitz SE Return Flow FMIC | Greddy Profec II Spec B BC | Apexi N1 Turbo Back Exhaust

  8. #8
    back into it Chief Engine Builder
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    Default Re: Braking performance, over time.

    Quote Originally Posted by JetspeedCamry
    Aight thankyou for your replies!.

    As far as cooking them goes, i rarely do constant hard braking. I have hard braked them, but only to a stop, and never over and over again through a mountain run or whatever.
    The fluid has been changed once in that time, about 6 months ago. I have also new rotors too, about 1 year-1.5 years old. Rotors are still in top condition. No leaks as far as i can tell, there is no fluid external to the system and the resovoir is still topped up.
    Over the time ive done all the above things, the pads have never been changed/come out. Is it possible that somehow an air bubble has gotten into the system? How much air has to enter to be able to feel a difference?

    Thanks once again. +rep for you all
    youll find the other thing is the moister in the fliud that degrades it over time might be the culprit! dosnt hurt to bleed and flush the system once a year for normal driven car, 6 months and sooner if you give the brakes a hard time. i dont know what sort of driving you do but a set of metal kings and a disc machine along with a flush of brake fluid and you will have a good performance setup. the metal kings are a bit of a pain when cold but sensation value for money when up to temp.
    the ultimates will be better cold but the metal kings will eat them for breakfast when you are having a bit of fun or at a track day.
    best bet is you have the money to do it, is pick a performance pad that suits the driving you want to do. like everything with cars its always a compromise wether brakes,suspension,engine etc

  9. #9
    Estranged Member Chief Engine Builder mullett's Avatar
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    Default Re: Braking performance, over time.

    I'm going with fluid. Fluid MUST be changed every 12 months, and 6 months is much better. In a sealed system, after 6 months the fluid will absorb enough moisture to drop the boiling point of the fluid by 100degC. And if it's been boilded a couple of time, it gets worse.
    It could also be your master cylinder or calliper pistons leaking. If this is the case, it's time for a bit of a rebuild of the braking system (not that pricey).

    Brakes aren't something you want to stuff around with...

    RM.

  10. #10
    Altia ER34 GTT Domestic Engineer JetspeedCamry's Avatar
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    Default Re: Braking performance, over time.

    ^ Yeah, ill flush the fluid completely, change the pads (since the probobly need changing anyways, and inspect all the seals/pistons for leakage and what not.See how we go!

    Thanks for the replies! Answered my question perfectly.
    Kind Regards,
    Kurt.

    1998 ER34 ニッサン スカイラインGT- T
    RB25DET 5 Speed Manual | Blitz SE Return Flow FMIC | Greddy Profec II Spec B BC | Apexi N1 Turbo Back Exhaust

  11. #11
    Just Another Part Time Grease Monkey
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    Default Re: Braking performance, over time.

    I would go with the fluid answer, but it could be a bubble in one of the flexible brake lines

    If you have checked for leaks (look up under the dash as well), changed the fluid, removing all the air at the same time then climb under and check it out. If the lines let go there will be no partial brake loss and your temporary braking technique might be the next big thing on the road.

    You can get new sets made at a hose shop. They seem to have every type of end required and it will be cheaper than original.

    Another possibility is a cracked caliper housing and it flexing slightly under load.

  12. #12
    Altia ER34 GTT Domestic Engineer JetspeedCamry's Avatar
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    Default Re: Braking performance, over time.

    Quote Originally Posted by BrianRA23
    Another possibility is a cracked caliper housing and it flexing slightly under load.
    Interesting suggestion..ill check that out
    Kind Regards,
    Kurt.

    1998 ER34 ニッサン スカイラインGT- T
    RB25DET 5 Speed Manual | Blitz SE Return Flow FMIC | Greddy Profec II Spec B BC | Apexi N1 Turbo Back Exhaust

  13. #13
    Hopefully soon a 5S-GTE Chief Engine Builder MWP's Avatar
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    Default Re: Braking performance, over time.

    What do your rotors look like?
    They shouldnt have a mirror finish... they should have a dull appearence.
    If they are shiny, take seom wet&dry sandpaper to them, see if that helps.

  14. #14
    Altia ER34 GTT Domestic Engineer JetspeedCamry's Avatar
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    Default Re: Braking performance, over time.

    If i remember correctly, they have a "concentric circle" look to them...dull yeah. Ill take a pic later on and see what you guys think.
    Kind Regards,
    Kurt.

    1998 ER34 ニッサン スカイラインGT- T
    RB25DET 5 Speed Manual | Blitz SE Return Flow FMIC | Greddy Profec II Spec B BC | Apexi N1 Turbo Back Exhaust

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