John1320

Longtime reader 1st time posting. I've had my 2009 LS460L For approximately 3 years. In the last month I replaced the bushings, Air Suspension (with airnott) and (ABS module.. a new oem one from a legit online verified dealer 44050-50110). All with information provided by this fourm. All work done my self with proper techstream and lots of reading. I initially kutagrad my abs module by replacing my rear brake pads Without the info i now have. Oops.. expensive lesson learned. After a week of driving it I noticed my pedal would get spongy. Hooked up the mongoose plus with techstream. Found the accumulator was dropping to the 3volt mark after a couple brake presses..Pump kicks in and back to 3.6v. Let it pump up and waited. No drop in pressure unless i press the brakes. Has the brake booster (fake master cylinder) gone out? It's always felt weird. I can't find anything pertaining to this issue on the forum. Please help!
I'm about two seconds away from taking the car out back and shooting it..

BlazeViper

Try a linear valve offset/relearn? Mine was way too touchy until I did it properly.

John1320

I reset the memory and performed the linear valve offset learning again. I get 3 brake pedal presses before the pump kicks in. Idk if this was normal behavior before. My brakes are and have been working properly since the replacement.

Does anyone have a count on how many brake pumps it takes to get the booster pump to kick in? I'm curious to know if it's within the normal limit. I didn't t pay attention before. I would be curious to take a poll so we all could have a good baseline of what the norm is. Considering all the brake issues with this car.

Striker223

Mine is 8-12 and it was replaced right before I got the car

miket000

I think you're good with 3.

On my wifes gs450 I get 3 times pushing the brake pedal fully to the floor for 1 second. 4th time motor runs. Brand new actuator / motor assembly installed last year.

My 07 460 with its original tired actuator gets 1 push to the floor before the motor starts. If I look at this car the wrong way it'll turn the motor on for a second. I've been milking it along for the past 3 years. Still no faults

John1320

I would love to know whats causing that. At least now I really have to listen for the actuator to kick in. When it wasn't working properly it was much louder.

Im about to do the unthinkable. And findout the root cause of this abs block of aluminum that costs as much as an entire used engine for the same car.Im going to take a bandsaw and slice my actuator in to as many sections as i can. I want to know what part failed... and I've never seen any data at all about the failure mode.. the abs block isn't serviceable but I'd still like to know. I'm weird like that

Striker223

Its the plunger seats, they wear out and can't seal anymore.

lexusls4

If this isn’t performed what will happened to the brake system . My buddy tried to perform this earlier and it wouldn’t even let him . He’s working on my car today and that’s what he mention .

BlazeViper

Calibrate the accelerometer and gyros. My car demanded that I do it first, I couldn't linear valve offset otherwise.