Just wondering if I've got a "lemon" or if anyone has heard of this; my Toyota Sienna's brakes have always squeaked, about 11,000 miles ago & the 2nd time I took it to the dealer (for both squeaks & going to the floor) they "couldn't duplicate it" but put a new master cylinder in. Well, now it's happening again, squeaking very badly when brake is applied & pedal started going to the floor when stopped on a hill... just like the last time. I bought this in Aug or 2001 with 100 miles on it.
Any help before I try to take thhis to the dealer again, would help!
Thanks!

Is the pedal going (to the floor) or just (Lower than it should) the squeeking can be from cracks in the pads, or glazing on the pads, and it can be caused by overheating of the braking system sometimes this can happen just from the drivers habbits, do you brake real hard? The pedal to the floor usually only happens when you are having a hydralic problem, if you are leaking fluid out a caliper or line and it gets on the pads that will cause a squeek also. If you do not find any brake fluid leaking its possible you could have a caliper binding up and it is not allowing your pad to retract so it is constantly dragging the pad on the rotor wich definitely will cause overheating of the brake system

This may cost you some bucks but I think you'll be a lot happier in the end. Toyota basically fired the manufacture who supplied the brake parts for your '01 Sienna. When they designed the '04 model, it was a whole new set up and a lot better brakes.
Here's what you need. Both rear drums have been updated to a completely new part. The wheel cylinders tend to leak behind the boots, so get them checked closely too. If you haven't had the rear shoes done yet, I highly recommend those with the new drums.

The budget way is to have the rear brakes cleaned and adjusted, then apply some BG anti-squeal (most dealers have this) to the shoe surface. Then, I affix 1.5 oz stick on wheel weights to the rear of the backing plate to dampen the squeal vibration.
Yes, this is all coming from the REAR brakes, but on occation I see the front caliper slide pins seize and cause a sinking brake pedal feel.
Good luck.