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gvzookdriver

az supporter
Joined: Mon Apr 13, 2009 11:30 pm Posts: 1833 Location: Brisbane
Vehicle: Sold zuk got a Bt50
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 Posted: Thu Jan 31, 2013 5:43 pm |
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I am having a few brake issues.
I have 4 wheel disk conversion but the pedal is very soft. When coming to a complete stop you need to push it about half way down to stop completely. But while sitting there I need to keep pushing the pedal till it nearly on the floor other wise it will start rolling.
Is it my brake booster or MC? Would a GU MC fix my problems? Or could it be something else completely different?
_________________ bt50 now but still love the zooks
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kenny.G345
Joined: Mon Nov 21, 2011 9:27 am Posts: 68 Location: Hobart, Tasmania
Vehicle: SWB sj70
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 Posted: Thu Jan 31, 2013 6:22 pm |
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Have you tried bleeding the system?
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royce

omnipotent being
Joined: Sun Jun 11, 2006 11:30 pm Posts: 17216 Location: Pluto
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 Posted: Thu Jan 31, 2013 6:27 pm |
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for the keep pushing the pedal, does it creep away from you? if so its likely the master cylinder is leaking, pull it off the booster and check for wetness there
as for the pedal height, its probably air, you can clamp off various flexi hoses and see if you get a pedal but its probably best to sort the dropping pedal first incase its related
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Ace
Joined: Fri Dec 28, 2012 11:26 am Posts: 127
Vehicle: 86 SJ413 dings / rust / 30's
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 Posted: Thu Jan 31, 2013 6:29 pm |
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Vit or SJ, are you auto and referring to the sitting and rolling, did you just do the rears or go to lwb vit discs at the front as well? (am just assuming its not that sweet lookin lwb) apparently mid / late 90's subie MC's are the way to go.
No leaks out of your 2nd hand calipers or air in the system? Am almost tempted to make some blind female 3/8 unf "blanks" - if that makes sense so I don't keep loosing the fluid out of the rear lines and spend ages bleedin them.
If only the rears done it should stop it better than you describe
Do you have to pump the pedal to build pressure?
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Gwagensteve
Joined: Thu Feb 26, 2009 10:30 pm Posts: 13007 Location: Melbourne
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 Posted: Thu Jan 31, 2013 6:32 pm |
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It's not the booster.
I think you need to supply more information.
What MC do you have in the car? What rear calipers? Does the pedal pump up? If so, how many pumps? How long does the pedal stay hard once it's pumped up?
I think you still have air in there somewhere, but it's not surprising you have a soft pedal if you still have stock MC. Drums don't need as much fluid movement to work compared to discs but require more pressure, but even with a low pedal, a stock MC should stop the car fine.
If you want higher/harder pedal then the 2 bolt GQ MC or Forester GT MC will achieve this. Once you get the feel right you can mess around with the booster. The booster won't revolutionise the feel of the brakes, it should only lighten the pedal.
In any case, you only ever bleed the brakes with the engine off, so pedal feel will be unboosted whilst you're bleeding - you'll know if you have the brakes right - the pedal will be high and hard.
Steve.
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gvzookdriver

az supporter
Joined: Mon Apr 13, 2009 11:30 pm Posts: 1833 Location: Brisbane
Vehicle: Sold zuk got a Bt50
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 Posted: Thu Jan 31, 2013 7:11 pm |
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Royce - no it does not creep away from me i just notice I'm starting to roll and have to push harder on the pedal. Ill take the MC off and have a look i had a quick look over each wheel and MC joints and no leaks there but ill look further into it. thanks
Ace - it a sj the disc are Vitara LWB in the front and standard sierra in the rears.
Steve - It is standard MC, rears are standard sierra and vented vitara front, yes pedal pumps up but goes soft again after about 30 seconds and it takes about 3-4 pumps.
Im thinking about just getting a GQ or forester MC and getting some speed bleeders. and adjusting the booster while im changing the MC.
Is there anyone in brissie that would be willing to help as i haven't done anything like this before and would like a little bit of guidance
_________________ bt50 now but still love the zooks
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royce

omnipotent being
Joined: Sun Jun 11, 2006 11:30 pm Posts: 17216 Location: Pluto
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 Posted: Thu Jan 31, 2013 7:23 pm |
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when you bleed the fronts, you need to unbolt them and slide them around so they sit like they do in a Vitara, otherwise the bleed nipple isnt at the highest point
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Ace
Joined: Fri Dec 28, 2012 11:26 am Posts: 127
Vehicle: 86 SJ413 dings / rust / 30's
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 Posted: Thu Jan 31, 2013 7:25 pm |
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bigger brakes require more force with the same master as is my understanding, sounds like an air issue to me. If both f+r are larger its prob not a bad idea to upgrade the master to match
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atari4x4

az supporter
Joined: Mon Dec 11, 2006 10:30 pm Posts: 34842 Location: East Radelayed
Vehicle: SV420+SV620 Vitara's
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 Posted: Thu Jan 31, 2013 7:25 pm |
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royce wrote: when you bleed the fronts, you need to unbolt them and slide them around so they sit like they do in a Vitara, otherwise the bleed nipple isnt at the highest point 
_________________ You're just hating because you don't understand
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gvzookdriver

az supporter
Joined: Mon Apr 13, 2009 11:30 pm Posts: 1833 Location: Brisbane
Vehicle: Sold zuk got a Bt50
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 Posted: Sun Feb 03, 2013 4:33 pm |
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_________________ bt50 now but still love the zooks
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atari4x4

az supporter
Joined: Mon Dec 11, 2006 10:30 pm Posts: 34842 Location: East Radelayed
Vehicle: SV420+SV620 Vitara's
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 Posted: Sun Feb 03, 2013 4:45 pm |
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have you tried bleeding the calipers as per royce's post?
_________________ You're just hating because you don't understand
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gvzookdriver

az supporter
Joined: Mon Apr 13, 2009 11:30 pm Posts: 1833 Location: Brisbane
Vehicle: Sold zuk got a Bt50
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 Posted: Sun Feb 03, 2013 7:05 pm |
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Yeah I did. its better but not that much. Ill give it another go when i get more fluid
_________________ bt50 now but still love the zooks
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Gwagensteve
Joined: Thu Feb 26, 2009 10:30 pm Posts: 13007 Location: Melbourne
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 Posted: Sun Feb 03, 2013 7:12 pm |
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Just out of interest, did you run the MC out of fluid when you were working on the brakes? If so, you need to bench bleed the mc, or you'll be fighting air forever.
Just a thought. As I said, with your setup the pedal will be low but shouldn't pump up.
Steve
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gvzookdriver

az supporter
Joined: Mon Apr 13, 2009 11:30 pm Posts: 1833 Location: Brisbane
Vehicle: Sold zuk got a Bt50
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 Posted: Sun Feb 03, 2013 7:40 pm |
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Never ran out of fluid noticed it was getting low so thought I won't try and go around again just to make sure I got it all
_________________ bt50 now but still love the zooks
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