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No Brakes! HELP!

Discussion in 'Diagnosis/Help' started by scottjackson1209, Mar 30, 2015.

  1. scottjackson1209

    scottjackson1209 Well-Known Member Donated!

    So after swapping in my new motor I am having a problem with my brakes. I can build pressure in the lines by pumping the pedal but after a while the pressure is gone. The fluid level is good (although it has a black tinge to it. Maybe oil from when my car spewed it everywhere?) I bled all 4 corners and am still having the issue. The level doesn't change so I don't think its a leak.

    I have double and triple checked the vacuum line going to the master cylinder, the one way valve is allowing vacuum but not allowing boost to enter...all the connections are tight. I'm at a loss. I have a spare master cylinder that I can try...perhaps it's the seals in the master cylinder due to possible oil contamination? if this is the case what other seals should I worry about? I have 4 spare calipers that I can transfer over if I need to...what about everything with the ABS lines? my ABS doesn't work anyway so I have thought about getting brake lines from a non ABS car to replace these and remove some clutter.

    Any help is appreciated as always! Thanks guys!
  2. 187flatliner

    187flatliner Seat Breaker Donated!

    id change out the master
  3. toyotawes

    toyotawes Active Member

    Agreed, sounds like the master cylinder is leaking internally.
  4. ST165-2765

    ST165-2765 Well-Known Member Donated!

    vacuum has nothing to do with the hydraulic system. Vacuum goes to your brake booster and makes it easier to press the brake pedal....that"s all it does, if you disconnect the vacuum it will just make the pedal harder to press but the hydraulic system will still
    function the same.

    You can try replacing the master cylinder but it is made up of 2 pistons for safety with 1 piston working the front left and rear right calipers and the other piston operating the front right and rear left calipers so it is very rare to have a total brake failure you should have at least 50% brakes.

    The only way to test your ABS actuator is with a special tool from Toyota so your kind of screwed there.

    Is your ABS light on ?
  5. scottjackson1209

    scottjackson1209 Well-Known Member Donated!

    Perhaps my title is misleading. I was still able to stop but the pedal was VERY soft and the brakes felt like they were maybe 50% or less. Once I pumped it a couple of times I could build pressure again. So possibly a faulty piston?

    ABS isn't working...when I did my swap i left out the wiring for it (actually I had to get a replacement fuse box and replacement didn't have the provisions for the ABS wiring so i left it out). the next step is just to remove the extra lines and the junction box to get rid of some weight and clutter.
  6. scottjackson1209

    scottjackson1209 Well-Known Member Donated!

    Alright so I swapped out the master cylinder and bled all 4 corners and I'm still having issues. It feels like it is a bit better but the pedal still randomly goes to the floor with very little back pressure from the brakes. Could this be a problem with the proportioning valve? or should I start replacing calipers?
  7. ST165-2765

    ST165-2765 Well-Known Member Donated!

    if your not loosing (leaking) fluid then your calipers are ok

    You either still have air somewhere in the system or a problem with the ABS

    I do believe that on ABS cars the proportioning valve is built into the ABS unit

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