grinding sound from brakes/under the hood . video inside

[2001LC]

 

[medtro]

I took the motor to an electric shop here in town that rebuilds starters and alternators. They have had it for 2 weeks and today said there is nothing wrong with the motor.

I don't know where to go from here.

The grinding sound has to be the motor. What else is moving with the brakes when the car is parked.

The noise could be from the accumulator if the motor is good. Please see post from @PADDO

Get the booster motor to run by bleeding down the pressure and then monitor the motor and accumulator while it re charges. Hood open, ignition off and pump the brake pedal 40 times to bleed off pressure. Ignition on (don't start) and the booster motor will kick in, now try and identify if it's the motor brushes/commutator grinding itself to death or hydraulic hammer from the accumulator. Use a long screw driver to your ear, or feel the vibe, stethoscope etc. It will be one or the other I believe. Monitor the differences in brake fluid level between when there is no pressure (fluid highest) and charged (lowest) mine drops around 11mm and this may indicate if your accumulator has lost some charge but not enough to throw a code yet. Time how long the recharge takes, mine takes 29 to 30 seconds, iirc the fsm says less than 40 seconds. This time will vary on things like your battery charge and brake fluid viscosity but it's part of the brake system checkout procedure. You can also check the cold resistance of the motors rotating cct - brushes, commutator and rotor winding - should be around 36 ohms? It's all in the fsm.

Toyota accumulator can be had at a reasonable price from Toyota 47950-60010 (4795060010) ASSIST, POWER BRAKE: Buy genuine car parts - Amayama

 

[bdruff]

I've been driving it for 2 days now. Everything is working perfectly. Fluid level is set correctly.

I looked at Walmarts service. No mention of toping off fluids. I've owned the truck for less than a year. I've never touched the brake fluid but maybe that was the problem.