alufront

Im a lexus true fan, my first car was a 1992 lexus ls400. I have owned all generation of the ls400 up to the 200 model. Never had a mayor mechanical issue on any of the lexuses that i have own. in the last 7 month , I countered the following problem. When I brake, at any speed, the brake pedal is extremely low, brake shudders and the steering wheel shudder after 50 miles per hour..

solution that I have tried.
1- new OEM brake master cylider
2-new set of four calipers
3-new set of brake rotor,slotted and drilled.
4- new brake pad,all 4 wheels
5- vacum the whole brake sustem,new fluids.
6- change my oem wheels to gs300(2007) wheels and tires

afterwards, the whole car condition seems better, but still not up to my new car standard when I had it 7 years ago.

after 2 month, the brake is again extremely low, brake shudders and steering wheels shudder when i brake above 50 miles per hour.

Any suggestions???????

Alufront

PureDrifter

iTrader: (10)

how do you "vacuum" the brake system?

methinks u have a leaking line somewhere and need to do a proper flush with some UV dye and then wait a week of driving it to look through the whole length of the lines to inspect for leaks.

the fact that it shudders only >50mph tells me you have either a wheel balance issue (very likely) or a busted trans mount (likely, but not as bad vibrations).

also have ur mech. check all the bushings int he front end of the suspension, a few strategically placed cracked/dead bushings would cause the front end to shift slightly when excess braking force is put upon it (ie-50mph+ braking)

skperformance

iTrader: (6)

bad shocks , broken strut rods, need new brake lines

steveski

Just to chime in on the suspension possibility. I always had a shimmy on the highway and had the tires balanced repeatedly. After I replaced the upper CA's the car is smooth now. So checking the suspension components is definitely a good idea. I never would have thought the CA's could cause a shimmy.

My brakes used to do the same thing as yours and after I resurfaced them they were and have been fine. Good luck.

alufront

I appreciate all your comments-!!!!!!!!!

I have just done the following today:

1- new shocks and spring (all oem)
2-new upper and lower control arm,front and rear.(oem)
3- new links front and rear(oem)
4- new engine shoes
5- new engine mount
6-my tires are new from my Gs 300 2007.
7-bleeded the brake lines by opening ALL the valves OF AL 4 WHEELS and let it drop by gravity.

I had a test drive right after, the whole car is tighter ,but the brake is better, but when I brake , the first step is low, and then the second(pumping the brake) step is always higher, but still not a solid as when I got it new. even a camrys or corollas brake feels better.

PLEASE HELP.

ALUFRONT

skperformance

iTrader: (6)

If it takes a second push to get firmer that is normal as with all cars.
Change your brakes and don't do a gravity bleed it needs to be pressured out by pressing the pedal. Change your lines for the most drastic difference.
Normally it is the booster that has a failing seal when the booster reacts that way but you said you changed it already. I would make sure your booster is getting enough vacuum as well.

CK6Speed

iTrader: (1)

What I have noticed with all the Lexus cars I've owned (93 SC400, 94 ES300, 99 LS400, and 04 RX330) is that the brake pedal feel isn't really that great compared to other cars I've owned. It never felt as firm and also seemed to sink further down than my other cars. What I have noticed though is they all had great stopping power. Too me they never felt good, but they sure stop the car well.

alufront

Skperformance:

agreed 100%. What lines do I need to change,just the rubber ones that is attached to each of the calipers????????

alufront

alufront

Mostly true, in order to discard that possibility, I drove another ls400 1999, and the brake pedal was slightly higher and retained more pressure. My Ls at idle, I can press the pedal all the way to the floor. I dont think that is normal, when I put the trans to drive then it will gain heigh

alufront

I will definetly do a whole system bleed. But should my brakes go all the way to the floor when the car is at idle, (of course you must press the pedal hard)
at driving speed, it will retain more altitude(pedal).

alufront

I meant bleeding the system. Since the whole purpose is getting all posible air particles in the fluid. Which I believe it caused the first pres to the pedal to be lower than the second one/.

JBrewster

Sounds like you have air in the lines now. Start with the brake that is furthest away from the master cylinder and have somebody pump the brakes while you open the bleeder valve. Then move onto the next furthest away brake and continue until you've bled each line.

skperformance

iTrader: (6)

I am going to try an see if the fittings are close to a rubber line from an IS 300 if they are we will know what is needed to order a set that are stainless steel which are way beyond the rubber ones.

alufront

Im going to purchase the Oem brake lines(rubber ones for the 4 calipers)
I will let you know my results. Thanks

skperformance

iTrader: (6)

Can i have your old lines?