2003 Cannot Eliminate Soft Brake Pedal

[jmgtp]

Hi Everyone,

I am working on a 2003 Corolla (about 130k miles) that had two issues, a warped rotor causing a pulsation under braking and a soft brake pedal that offered lackluster braking.

I had both front rotors machined and replaced the front pads and rear shoes with Weaver semi-metallics. The pulsation issue has been eliminated however the soft brake pedal and weak braking remain.

Since I can push the brake pedal to the floorboard this does not appear to be a power assist issue and feels like air in the brakes is the culprit. I first adjusted the rear shoes so that they just slightly drag on the drum. I then did the self adjust by braking in reverse a dozen or so times. I then vacuum bled both wheel cylinders and both calipers while maintaining fluid level in the reservoir. Still, the soft pedal persisted. I then bled the brakes via the 2 man method - still soft pedal.

The brake hardware passes the visual inspection. The seals on the wheel cylinders and caliper pistons look dry and the rubber lines do not show signs of deterioration. The calipers 'float' freely on the pins and there is no binding. With a helper pushing the brake pedal I held the rubber lines in hand and do not feel them ballooning/expanding. I'm not sure what else to check and I don't want to start guessing at things to replace since that can become expensive quickly.

I suppose air could be in the master cylinder but I'd be amiss as to how that could have happened on a sealed system that has no leaks and has never been run low. I've bench bled master cylinders before but is there any way to do it installed on the car without disconnect the brake lines? I have a good vacuum bleeder and a so/so pressure bleeder.

Your thoughts are appreciated.

[gideon1331]

Do you have ABS?

Sounds like air stuck in the ABS actuator. If so, bleed the brakes with the ignition switch in the On position (engine off). I've experienced this on another Toyota with ABS.

[jmgtp]

Thanks for the reply.

No, the car does not have abs. Any other suggestions?
Thanks again!

[mikered30]

Do a complete flush and bleed your brakes.