Thoughts on a soft/spongy brake pedal??

My brake pedal as been pretty soft for the past few months now.

-Ive tried bleeding the brakes from each wheel

-tested my master cylinder by disconnecting the brake lines and plugging both holes. When I did this the pedal was Rock solid which to me indicates the master is fine.

-did the classic brake booster test where you put your foot on the brake with the car off, then as you turn the car on see if the pedal goes down or stays stiff. I did this and the pedal was easy to push which to me indicates the booster is fine.

My suspicion now is it's the abs system, what do you guys think?

Vehicle: 2007 Lexus IS250 AWD

21 Answers

  • Dan
    Lv 4
    4 months ago
    Favorite Answer

    The first step is to carefully inspect all the hardware; pads, calipers, wheel bearings, slides and more, then bleed the brakes properly if everything checks out. If the pedal is still soft after you're sure all the aforementioned are good then it is possible for the ABS module to cause this problem. Ford had big problems in this regard, not Lexus though.

  • 4 months ago


  • 4 months ago

    You still have air in the lines.. YOU have to belled them in the right order to get the air bubbles ALL OUT.. IT IS NOT the ABS sensor.. That is mounted on the back of the hub IT IS AIR.. you did not get it all out.. be sure you keep the MC full when bleeding them and go in the right order...

  • 4 months ago

    Make an appointment with a Toyota Dealer and ask them to; Change the brake fluid if you haven't had it done every two years as Lexus recommends, *pressure bleed your brake system, check the brake hoses, brake lines, caliper slide pins, caliper pistons, caliper brackets for rust and check all brake hardware.

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  • JetDoc
    Lv 7
    4 months ago

    If you don't know what you're doing... STOP SCREWING WITH IT! Take your car to a REAL mechanic and pay to have your brakes fixed before you end up in an accident.

  • 4 months ago

    Have you even removed the calipers to inspect the brakes?

    Frozen brake slide pins or rusted caliper brackets that keep the brake pads from moving freely will cause a soft pedal.

    Source(s): Mitsubishi Master Tech
  • 4 months ago

    You've still got air in the system. Bleeding needs to be done in the correct sequence and in the correct manner, and you clearly haven't done that. You can't take chances with brakes, get it seen to by someone who knows what he/she is doing.

  • Geo
    Lv 6
    4 months ago

    You KNOW you have Air is the system, and if you didn't BLEED the ABS Module that's where the air is. Sometimes you have to Pressure Bleed the system where you put an adapter on the Reservoir and pump to 14psi. OR go the other way and Vacuum Bleed it. The Mighty Vac Tool has a brake bleeder adapter. That is a very cool tool you should buy. And buy the Flare Nut Wrench for the ABS fittings so you don't round off the flare nut. IMPORTANT: Don't ever let the Reservoir run dry! Look here:

  • Phil M
    Lv 7
    4 months ago

    Air in the lines. Taking the lines off introduced more air.

    • M.
      Lv 7
      4 months agoReport

      @fdeebz: You said: "Regardless if there is air in the lines, something is leaking".

      So WHERE do you SEE a leak? WHERE is there BRAKE FLUID??

  • 4 months ago

    i would have a mechanic check it out

  • Anonymous
    4 months ago

    Unsafe. As were told In driving lessons early on, the pedals should have to be forced down if they are in good condition. They should also spring back up if pressure is taken off.

    I would get a mechanic to look at it.

    • fdeebz4 months agoReport

      Yes I understand this is unsafe which is why I'm trying to fix it. I'm asking for your thoughts on what the issue could be

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