ST165 brake upgrade spongy pedal...

Discussion in 'CHASSIS' started by George611, Aug 11, 2012.

  1. George611

    George611 Paid Member

    Right ive jus done the st165 upgrade and the pedal has quite abit of travel before anything happens, ive bled them for ages til no air bubbles are coming through all 4 brakes aswell. brand new dot 5.1 fluid too. i know the pedal will firm up a tad once the pads have bedded in but even so there will defo be more travel than there should be,
    i was told i may have to move the pivet point of the brake pedal to compensate for the more fluid being required by the twin pots.

    is there any way of making the pedal feel better?

    im new to brake upgrading so bare with me lol.


    Thanks in advance.
     
  2. Texx

    Texx Administrator

    How much pedal travel do you have before you can feel any resistance?
     
  3. weeJohn

    weeJohn Paid Member

    I had no difference in travel when I fitted these on 2 different cars. Have you bled the rears as well as the fronts?
     
  4. George611

    George611 Paid Member

    ive bled all 4 about 2 litres of fluid no air bubbles fluid flowed lovely,
    theres about 2inches travel the standard brakes had about an inch.
    it dont feel right really not happy with it when it bites its nice tho.
     
  5. weeJohn

    weeJohn Paid Member

    It sounds like they are working when you are getting bite, but that is to much travel. Have you took a wheel off and looked at the calliper when someone else is pushing the pedal? Worth doing with the engine running so the servo is helping.
     
  6. George611

    George611 Paid Member

    yeah il have to give that a go tommorrow and see whats happening, jus baffled as to why its sp spongy :S
     
  7. weeJohn

    weeJohn Paid Member

    If the calliper is not secured or there is something flexing it could give the feel of a spongy pedal before both pads hit the disc.
     
  8. George611

    George611 Paid Member

    everythings on there nice and tight so im abit confused still, got to have it all off again now becasue the discs are warped quite badly!
     
  9. Gryzor

    Gryzor Administrator

    is the bleed nipple at the top or the bottom of the caliper on the wheel ?
     
  10. George611

    George611 Paid Member

    it isnt touching if thats what you meen ?
     
  11. Texx

    Texx Administrator

    If you have the calipers mounted so that the bleed nipple is at the bottom of the caliper, you won't be able to bleed the air out of them.
     
  12. George611

    George611 Paid Member

    ahhh got cha! tad confused then lol, nah the nipples facing upwards (Y) they bled fine i done 3bottles of fluid! no air coming out at all it was jus clear fluid coming out, the pedal was abit soft before the upgrade no where near as soft as now but still a tad, dont spose it could be the master cyl on its way up the swanny would it?
     
  13. Texx

    Texx Administrator

    If you pump the pedal with the engine running does it firm up at all or is it still the same?
     
  14. George611

    George611 Paid Member

    It firms up but not spectacularly as it should really..theres so much travel its kinda off throwing..
     
  15. Texx

    Texx Administrator

    Are you using braided brake hoses or standard brake hoses? If they're standard hoses you could try clamping them and see if the pedal feel changes. If the pedal firms up then at least it confirms the problem is with the calipers, if it stays the same then the master cylinder possibly requires some attention.
     
  16. weeJohn

    weeJohn Paid Member

    I dont know what discs you are using, but are you using spacers behind them to center the disc in the middle of the caliper? The spacers need to sit tight against the hub, the projection that centers the disc and hub has a bevel on it, if the spacers dont have a recess for this the spacer wont sit on the hub flush. Take the disc off and check its all sitting on the hub tight.
     
  17. George611

    George611 Paid Member

    braided hoses dude, il have a look what there like under pressure, yeah im using 3mm spacers behind the discs im pretty sure they was sitting tight when i put them in but il have a quick look ina mo when it stops raining to make sure. i did think could it be something to do with the spacers but they sat pretty tight as i say i shall have a butchers in a bit :)
     
  18. weeJohn

    weeJohn Paid Member

    If they dont its just a matter of filing a bevel in the back of them so they clear the radius on the hub.
     
  19. George611

    George611 Paid Member

    Didnt get a chance to look last night pissed down all night :( il get out there now n check, hoping thats what it is tbh i cba to piss about with other discs lol
     

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