Originally Posted by jonas's RX

Guys

By all means I’m not suggesting this is what is normal in cars but for brake failure, you must downshift the car from 6 or the 5th gear to the lower gear and after the car slows down use your parking brake.

The immediate response is to step on the brakes in a panic mode but you must
not panic. The SC has airbags and the worse it can happen you lose the car in
an accident but you are ok. You guys can test the downshift approach when you are
driving so you know how to downshift but it is not hard. The SC has the Z gate shifter
which makes downshifting easy.

By all means, I’m not suggesting this is ideal but downshifting will slow the car down and
the car will stop. Keep your area around the shift clear of crap. I know drivers have all kinds
of crap around their gear area.

This is the first time the pump did not make the loud noise. In all the other instances that i
remember hearing about this issue, the Pump went into a loud screeching mode before intermediate failure.

I had 4 SC with low miles and what I have seen so far are the higher mileage SC with 75-100K+ miles having reported failure. The other option is to replace the ABS MC pump. I have a mechanic that could replace the part but if you plan to keep the car, might be a good idea to
replace just the pump or the entire unit.

The SC is solid from engine to drivetrain to the electronic and the top. This is probably the only gremlin on the SC. All cars will have issues as they age. This issue is obviously more
troubling.

If you listen to your SC at idle,I guaranteed you will hear the ABS pump pressurizing every few minutes which is normal operation. All my 4 SC’s did this. If you don’t hear the pump
pressurizing every few minutes, that also could be a warning and to immediately go to the
dealer to have your ABS MC looked at before problems including failure.

Originally Posted by jonas's RX

DB

Your sampling size is very troublesome.

I recall seeing another SC owner had the failure
and he did exactly what I suggest and was able to
slow the car down. With 10 seconds to react, most if not
all drivers regardless if you are a novice driver or a
professional track driver will probably not be able to react
without an accident.

The other option and obviously too late for you is all SC owners
with 75K or more change the ABS MC out. I’m at 49K and will
replace the entire unit as soon as I hit higher mileage.

Originally Posted by dbryan

Probably a good idea. There is a link here for a rebuild kit which is under $80.

Originally Posted by jonas's RX

https://www.clublexus.com/forums/sc4...off-brake.html

Here is the thread by one of our past members.

Similar and as troublesome

Originally Posted by dbryan

My apologies if this has been covered elsewhere. I did try to search for it. I was in an accident yesterday due to brake failure of my beloved 2004 SC430. My poor baby was hurt but it should be repairable.

I was coming up to a light and was braking normally when suddenly I heard a click and suddenly my foot went to the floor. I hit the brakes again and it caught for a second at full brake and then went to the floor. This happened 2 more times with the last time the brakes locking up and then went to the floor again. Fortunately the impact had slowed enough that no airbags deployed. Baby is going to need a new bumper grill and hood and nobody was injured. The brakes started working again and I was able to slowly move it into a parking lot. I guess I'm lucky because had no one been in front of me I would have rolled out onto one of our busiest 6 lane roads.

I'm trying to figure out what happened. I started wondering if I kept missing the brake but lets face it there is no room to miss the brake To do so would have had my foot in the accelerator. Does anyone have any ideas on what could have caused this intermittent brake failure? Is it computer controlled or a possible electronic failure? I need to make sure whatever happened is corrected before I start driving it again.

Thanks for reading this. I truly appreciate this forums help. It has been a great source of information.

Originally Posted by TomDargan

1. Does anyone have the part number for the air bleed valve for the booster?
2. Is anyone gonna query Lexus or the Feds about the brake failure hazard?

Am I right these are the key takeaways?

Originally Posted by jonas's RX

Guys, the rebuilt kit will not resolved the pump ABS failure.

The “gold” pump motor attached to the ABS is the
main Issue. Once the electric motor pump loses pressure that
is when the ABS will fail.

If your ABS MC is not leaking fluid or you don’t notice
fluid leaking, change the Pump motor out and you
should be good to go.

You should also be hearing the pump “pressurizing” every few minutes when you are driving.

IF you don’t hear the pump pressurizing, then you should look into replacing the pump to avoid failure or have a mechanic look into the ABS unit

Originally Posted by RichardMor

This is a scary thread. No car design should allow total brake failure. DB, looking forward to hearing what you learn from Lexus, but I doubt there will be a definitive resolution for the rest of us. I had an ABS accumulator failure in an Audi A8 I previously owned and it caused brake fade (very hard pedal) but not total loss of function. We have an 06 with 136k, so I am particularly interested whether a new accumulator is needed (or if the design changed in 06). I never skimp on brakes. Scary.

Rich

Originally Posted by jonas's RX

IF you don’t hear the pump pressurizing, then you should look into replacing the pump to avoid failure or have a mechanic look into the ABS unit

Originally Posted by Wilson2000

Not sure how this could happen without a warning light. If it can, there's an open-and-shut, class action court case in our future!