2008 RX400h first time owner needs help with brake actuator assembly squeal at Park before shifting gear?

[jmoe2012]

Hello Dear Lexus Owners,

I recently bought a 2008 RX400h with about 140K miles and drive off. It drives fine out from the dealer but I noticed a short squeal when the car is started and drive off from Parking. When I depressed the brake pedal to shift the gear from P to R, I heard a noticeable squeal coming from the engine compartment. It's a short squeal like 2-3 second and it stops or may be repeat once or twice with about 10 second interval if I keep pressing down the brake pedal at the Park Position.

It never made that sound when the gear is in R or D position or during regular driving. It only squeals once or twice when the car is parked as the pump is pushing brake fluid but it can't because the line is full.

Is that the sign of the brake flush needed or air trapped in the hydralic lines or the actuator assembly starting to wear out?

I have seen videos of failing actuator on youtube but it's nothing like that at all. It's just a squeal or two at the Park position.

Is that normal for old RX400h or it's needing to go to the Lexus dealer?

I have a Techstream setup and may be able to flush the brake fluid myself if that's all it needed. I think I'll replace the pads and lube all the brake caliper pins before the flushing.

 

Thanks for your input, folks!

[RX400h]

A brief squeal coming from the engine compartment typically indicates that a drive belt needs to be changed or if recently changed, needs to be tightened.
Our RX400h has a small bit less mileage than yours and we have never had an actuator problem but since you are pressing on the brake pedal, I am baffled.

[jmoe2012]

2 hours ago, RX400h said:

A brief squeal coming from the engine compartment typically indicates that a drive belt needs to be changed or if recently changed, needs to be tightened.
Our RX400h has a small bit less mileage than yours and we have never had an actuator problem but since you are pressing on the brake pedal, I am baffled.

Thanks for chiming in! I confirmed the squeal (or squeak) is indeed coming from the brake actuator assembly with the help of the wife who presses on the brake pedal when the vehicle is running (ready) and the gear is in Parked position. It did make one or two squeal sound from the actuator assembly and then stops. It's like the relays or brake pressure pump is applied for a short time.

This noise can be heard with or without the engine running but the car is put on Ready state.

 

[RX400h]

Okay, you may want to review this web page:

http://www.diy-time.com/automotive/toyota/faulty-brake-actuator-brake-booster-pump-on-toyota-lexus-cars/

 

[jmoe2012]

Yeah. I saw that one before and I reviewed it thoroughly. I don't have any codes or any symptom of poor brake performance whatsoever. It never made any sound once it is shifted out of P to R or D gear. It's only heard when it's parked and the brake pedal is depressed.

I ran the Techstream and no fault and no DTC in ABS or the main ECU or anywhere. It's running well in driving or any other test I can perform. It's just that noise that makes me think if it's a sign of early actuator wear.

 

I have been digging info on this site and found it probably got to do with one of the TSBs posted by lemon in the sticky and required a correct bleeding procedure. I am not sure yet but it required jacking up the car about 22" off the ground and I don't have that high lift jack so I need to buy one before I can try it.

[RX400h]

Certainly, bleeding procedures have gotten far more involved over the years. In may cases, a special tool is required to cycle an ABS model. This is why I stopped bleeding my own brakes, many years ago. They didn't need to be done often enough to warrant my buying the special tool.