sbrown02

Anybody else experiencing rough braking when you find yourself having to hit the brakes hard to slow down in a pinch? What I mean by rough braking is not related to sound, but rather a jerky slow down motion instead of a smooth steady slow down when the brakes are pressed firmly (not to be confused with brake pedal to the floor in an emergency situation kind of braking).

Here's the scenario I've experienced 3 or 4 times in the past 3 weeks. I'm driving along 50-55mph on a city street and come to a light that turns yellow. Instead of running it (ok, I know what you're thinking) I apply the brakes solidly and the car begins to slow down quickly, but as it does its like the engine and the brakes don't seem to be in sync. It's hard for me to tell, but I think its like the engine down shifts, but instead of helping the car slow at a greater rate the spike in RPM's seems to impede the slow down. Or at least that's my perception of what may be happening.

Now I haven't tried to replicate this over and over again. It's just happend 2-3 times, but when I do find myself in a situation braking like this I feel like its just not working right.

All other normal (not hard) breaking seems to be fine. So, anybody else experiencing this or something similar?

Thanks

CrazyTrain

Is it pulsating like the way ABS is supposed to work?

sbrown02

No. In the situations I've experienced I'm not braking hard enough to engage ABS. Just hard enough that the engine has to slow down fast. I need to see if I can replicate it. Until then I wouldn't classify it as a problem, just something to keep an eye on.

Thanks

Franknyc30

ive had to slow down hard several time and havent experienced the anomoly you describe. i find the brakes on this car to be quite superior comparing to what i had prior. maybe there is something there for you to keep track of maybe not. keep us posted. also, there is a TSB on the GS350 where the car pulls to the left. you may want to keep an eye on that as well.

Fujifuzz

Abs Abs Abs

SGT

What you're describing sounds like ABS is kicking in. I've only been in one situation where the ABS did it's thing and I could definitely feel the brakes pulse and felt some jerkiness as the car tried to stop. This happened last winter when I was going pretty fast on the left lane of a highway in a snowstorm trying to make my way back home after snowboarding. The highway curved left and the divider was tall enough so that I couldn't see over it. As soon as the highway straightened out, I saw a plow truck on the left lane get increasingly closer at an alarmingly fast pace. I knew I wasn't going to be able to stop in time but I jammed the brake pedal and felt the ABS engage and pulsate. There were cars on the middle lane so I couldn't cut in. As I got to within 10 feet of the plow truck, my car slowed down significantly and I saw an opening on the middle lane so I switched just in time. Probably the scariest moment of my life but I'm grateful for the ABS and AWD.

IStoGS350

Where can I find this TSB? Mine pulled to the left until I replaced the stock 17's with some 19's and the Lexus Service Center told me I had a defective tire.

Franknyc30

I dont know where you can find the TSB, but i did read about it and it was confirmed by another post and my dealer. the work took one day to complete. I dont know if youre hiding the problem by switching to the larger wheel. My service consisted of replacing the front lower control arms (both sides). Wheel alignment, Balance all tires, and rotate the front left tire. All covered under warranty. My car now rides as crooked as a politician. Just kidding, problem was resolved by the dealer.

sbrown02

I really don't think it was the ABS kicking in. I've experienced ABS on other cars and felt the brakes pulsating and there was no pulsating going on. As I said earlier, I don't think the engine was downshifting correctly. The reason I think this is because as the engine slowed and came to a point where it had to downshift, it was like the engine RPM's spike higher than I would have expected. Which caused the car to jolt or lunge forward and which required more brake pressure so I could stop in time.

So instead of a rapid yet smooth and steady speed decline, it was smooth for the first second or two and then this lunge forward and then smooth for the most part as the engine came to an idle.

If it does it more I'll post back. Thanks

jjpxlala

I think its B.A..
(Brake Assist)
Basically, a brake assist system monitors the driver use of the brake pedal, automatically sensing an attempt to stop the car as a result of panic.

Nickc0844

sbrown, I'm having the same exact issue! I live about 30 miles away from my dealer, and had a tech drive while I sat shotgun...couldn't replicate the issue. It's not the ABS, it is a sync issue. Reason why I say that is because it happens to me every time I go down the same hill near home. It's like I'm in either 3rd or 4th gear and lightly tap and hold the brake in fear of the cops clocking at the bottom, but it feels like I "spike" the brakes since the brake assist kicks in. It's horrible!