dillon81

Hey Guys,
I have a 1999 LS 400 with only 60K miles and the brake pedal goes all the way to the floor as you keep applying pressure. I have brand new OEM pads on the car. The cars seems to stop fine but you just don't have that positive feel. I have been told that it can be a wore out master cylinder. Any other members with a similar problem on there 1998-2000 LS 400? Any input would be greatly appreciated.

Thanks,
Dillon

trukn1

Possible air in the lines. Did you bleed the brakes? Low brake fluid? Start checking the obvious things first before you start to throw money at a master cylinder.

dillon81

TRUKN1,
Thanks for the reply. I did take the car to the dealer and they checked for air in the lines but didn't find anything.

91LS400LEX

Sounds like the master cylinder is failing. I had a car do this (not a Lexus) and it was the master cylinder.

One thing I can say is that I have never had a brake problem on either of my Lexus (1990 and 1991).

trukn1

HUH?? You took the car to a dealer, with the brake pedal hitting the floor, and they didn't find anything wrong?? 2 things,,,

1. Demand your money back, since there is obviously SOMETHING wrong with the braking system.

2. NEVER go back there again.

That is ridiculous. As long as you have no air in the system, and the fluid is full, then it may very well be your master cylinder. I would get a second opinion from a reputable mechanic.

dillon81

TRUKN1,
I agree with you 100%. I don't care what kind of car you have, the pedal should never go to the floor. They said they did emergency stops with the car and the car stopped fine. However, the pedal should still not go to the floor as you keep applying pressure. As far as money, they never charged me anything since they didn't do anything to the car. And YES, I don't go to that dealer anymore.

JimsGX

dillon81,

If you don't have a lot of experience performing mechanical repairs, working on a car's brake system isn't a good place to start. I'd find a good independent mechanic in your area and have them take a look at it.

PureDrifter

iTrader: (10)

brake fluid is cheap. even GOOD brake fluid is reaonably priced. a master cylinder is easily a couple hundred dollars USED. go flush your brakes properly (or have it done) including the ABS block, THEN decide if you need a new BMC.

skperformance

iTrader: (6)

leaking piston seals also cause the same issue, I changed mine and its all resolved with my pedal touching the floor.

celsiorlee

hey dillon81 i got a 1999 ls400 that is doing the same thing i bled the fluids and it makes a complete stop, but the pedal goes down to the floor when adding pressure to the pedal. did you ever resolve your problem?

chicov8

celsiorlee did the bleednig make any difrence?
i do have same problem with my 02 gs430
did you try to pump brake pedal 10-20 times? when do that i got all warning lights brake, abs,vsc,vsc off and they disapear in a second or two ifter i stop pumping

anesthesia

Any follow up on this? My 99 ls400 brake pedal is not as firm like before when braking, ithe pedal goes down further before stopping, wonder if changing brake fluid will help, my pads still have at least 50% left.

RA40

iTrader: (6)

Barring obvious leaks in the lines and at the calipers, the first suggestion would be to change brake fluid and check for proper fill levels. Then check the vacuum lines leading to the brake booster, ABS, trac...

BlkonBlk96

I'm in the same boat. Replaced brake booster, master cylinder, flushed brake fluid. New fluid and bleed brakes, still same problem! I push pedal to the floor and get an air release sound. I'm at the end of my rope. Any suggestions?