FLLEXUS

Before I take it to the mechanics, I want to make sure I know the right things to mention to them and also to avoid possibly getting ripped off (I'm a chick).

Here's a description and audio of the sound that it's making: http://vocaroo.com/i/s1kw2kYW3j11

I'm just sitting in the driveway pressing on the brakes in this audio clip. You can hear me pumping on the breaks, then this mechanical winding up, motor-type sound, then the jerking sound. I have also noticed when at a stop, after releasing the brake pedal and making a turn I will hear a strange sound coming from under the brake pedal as well.

chiph9

That doesn't sound good at all. Could be the brake booster. Unlike other vehicles that use a vacuum diaphragm, the GX & LX use a motor-driven pump to add brake assistance.

It's an expensive repair, but one you don't want to put off (people who have had this replaced have mentioned costs in the $2000-2500 range). If it goes out entirely, your pedal effort will go way up, and you'll have a very hard time stopping (you may cause an accident).

Make an appointment to get it looked at. Consider getting the vehicle towed to the mechanic. Even if it's just a case of the brake fluid being low - it's a safety critical item. If they do top up the fluid, ask them were it all went (brake fluid doesn't evaporate - so there'd almost certainly have been a leak).

Here's the parts breakdown for you. The assembly is located in the engine compartment, bolted to the firewall on the other side from where the steering wheel & gauge cluster are (the other end of the brake pedal pushes on this). You'll have to remove the driver's side plastic cover to see it.

http://www.lexussouthatlantaparts.com/showAssembly.aspx?ukey_assembly=758572&ukey_make=1082&ukey_model=15663&modelYear=2003&ukey_category=21744&ukey_driveLine=8091&ukey_trimLevel=19100

Chip H.

jagsr71

Did you ever get this issue resolved? I have the exact same sound. I took mine to the dealership and their head mechanic was stumped. It's not throwing any codes. I continued to research it and it's not the same sound some are having with the brake booster continually being on and then screaching. Also, apparently that occurs past the 200k mark where the brake booster needs to be replaced. My clock is at 125k.
You would think it'd throw a CEL but I have nothing to accurately go by for a proper diagnosis. I also haven't experienced any loss of brake power. ??????
Has anyone else encountered this problem?