Losing brake fluid very slowly. Where from?

[Sporin]

Did you notice any increase in the buzzing of your MC pump?....with the leak, i suspect the pump will try to over compensate

I can honestly say that I've never heard that noise.

My issue was ALL in the vibes I felt through the pedal and having the dummy light come on to tell me the fluid was low.

It must be a VERY small leak because I've added maybe 2 cups of fluid over 2 occasions over the last 5 weeks or so and my pedal always felt firm.

 

[Sporin]

One last follow up... mechanic said it was "seeping" and looked like "a bad rebuild" because the caliper itself isn't old.

So I feel better about the tire shop not being responsible and just chalk it up to coincidence that I started noticing it at that time.

:roadkill:

 

[earthrealm]

I only hear the noise at night, in my driveway..when everywhere is quiet, but i have noticed that it coincides with the slight pulsing\tremor i feel on the brake pedal.

 

[andreylights]

any way to diagnose master cylinder or brake booster?

Figured I would continue this tread instead of starting a new one. Always was surprised by how long the brake pedal travel was. Like first 30% of the travel no braking was actually present only further that point but it was always strong enough. Wanted to make sure all the brakes functioning I have got new pads/rotors all corners and new calipers in the rear + brake fluid bleeding and flush.

It did not help with a brake pedal travel BUT now in addition to that my 07 4runner is slowly loosing brake fluid. I cant see anything under the truck and the brake lines and calipers seem to be clean and no spot that would suggest leaking. No trace of fluid on the floor of the parkade either.

That leads me to the conclusion that it might be cylinder or booster (at least other threads advise that) -- is there a way to diagnose that? Take them apart?