2003 Toyota Sienna Low brake pedal

RICKSHAK

MEMBER
2003 TOYOTA SIENNA
3.0L
6 CYL
2WD
AUTOMATIC
160,000 MILES

Low brake pedal which does pump up. Two mechanics bled and bled with no luck. 2nd mechanic replaced MC and still has problem. Mechanic thinks new MC is defective. I'm doubting this. Pads and shoes are new. Problem came about very slowly over the years.

1 Reply

CARADIODOC

MECHANIC
33,741 POSTS

Your last sentence is the best clue. This is typical of rear shoes not adjusted properly. They have to travel too far to contact the drums, then the pedal pressure starts to build up. This gets progressively worse over a few years as the linings wear down.

If you trust that your parking brake cables aren't rusted tight, you can lightly apply the parking brake. That will run the shoes out to the drums. At that point you'll have a good pedal that doesn't need to be pumped up.

The second clue is pumping the brake pedal produces a higher and harder pedal. The shoes take time to retract when they're released, but if you take another stab at the pedal before they retract fully, you don't have to move them so far to contact the drums. That's why the brake pedal gets better when you pump it. If you can pump it up to a good, hard pedal, and it doesn't sink slowly, that tells you there's no air in the system.