LBCDan

Every once in a while I get a grinding/squeaking noise when I release the brake pedal. I also notice it seems to be losing pressure when I hold down the brake. It happens intermittently, it goes away and then comes back. I took it to the dealer and they could not recreate the noise. I have 77K miles on the vehicle. Any ideas?

tommewin

Not sure about the sound, but if you feel like you're losing pedal pressure, maybe you have some air in your brake lines? Try bleeding them and see if that helps.

mhapsy

HI, can you tell me what you did to your car? cause i think i have the same issue. when i release my brake there is griding/squeaking and l loosing pressure, dealer told me it maybe the valve on the brakes or the brake booster. thanks

homer88

Have you found out the problem yet? My 04' RX330 has the issue now, 180K miles on it. Spent couple hundred dollars to replace the master brake cylinder (got the parts from amazon), but the problem remains. As stopping for red traffic signal, the brake pedal was pressed for couple minutes, then the noise which was like pressure released or leaked as releasing the pedal. I heard the noise coming from the parts connecting to the pedal, I do not know the name of the parts. I will have a mechanic to check.

homer88

Just checked the internet. I think that parts is called "brake booster", where the noise comes from. It is the vacuum parts enlarging the pressure to push master cylinder to move the brake pads. If it's defective or not completely vacuum, then there is noise. So, conclusion is - replace the brake booster.