Odd brake symptoms

Intermittently the brake pedal becomes hard to press. This lasts until I give it more then normal amount of pressure, then it seems to jump to the floor easily. After that its back to normal for awhile. Local mechanic couldn't duplicate and replaced the check value, but it has happened after the replacement.

Any ideas?

 

Intermittent vacuum leak? Hard brakes = failed brake booster.

 

crawl under the dash with a flashlight and look at where the brake pedal pushrod goes through the rubber boot and see if it is wet, if so, you are going to need a brake master cylinder.
with the motor off, press the brake pedal to bleed of any reserve vacuum out of the booster. With slight foot pressure push on the brake pedal and see if the pedal slowly drops to the floor, if so, you need a master cylinder. let the pedal come back to the top and start the motor, the brake pedal should drop slightly, this is normal. If the pedal does not drop and/or stays hard to push, you need a vacuum booster. Open the hood and with a helper, have the helper press the pedal as hard as they can and see if the booster assembly pushes away from the firewall, if it does, you have metal fatigue where the booster bolts to the firewall.

 

To add to what others have said, my vacuum booster also started to make sucking sounds as it was going out. Had about 1 day notice before it failed entirely. Toyota no longer has OEM brake master cylinders or OEM brake boosters available, so you'll have to go aftermarket or find a used one.