Guys,
I had posted this in the LS forum with little response, therefore I'm posting it here as well.

It's a 93 LS400 with 60K miles. I've had it since it had 40K and I'm the second owner.
A few months ago it developed a wierd brake problem. The pedal travel increased by twice as much as it used to. It's intermittent meaning while driving the pedal would be perfectly fine but the next time you're thinking of applying brakes the pedal would've travelled down. During stop and go driving it's not a pleasant situation. More over at times when the pedal travel increases the pedal feels spongy as well. The pedal seems to have a mind of it's own where it fixes itself back to normal without any reason.

I've taken the car to the local lexus dealer and at this point they've done the following :
1. replaced master cylinder
2. replced brake booster
3. bled the system three times already, replaced the brake fluid with new.
4. checked the callipers and lubricated them.
5. checked all the rotors and brake pads.


After all that work and 2000dollars, the problem is still there. The dealer at this point has given up and claims that it is normal for this model car. I do not agree with that statement since i've owned a smiliar model in the past and it did not have the same problem.
Any suggestions will be appreciated. !

 

Have they/you tried replacing the oem brake lines with stainless steel lines?

 

No I didn't but the other car I had never had the steel lines either.
I have another question related to this, I'm thinking the only thing that has not been thought of is the pressure buildup system that is connected to the brake booster/master cylinder.
Could someone please tell me where the brake sytem gets it's pressure after everytime the brake pedal is pressed and released ?
thanks.

 

Lexs400,
See my post in the SC400 forum for your brake answer. THe brake system gets it's pressure from the mechanical leverage of your foot against the pedal.

http://www.teamscr.com/grmbrakes.htm

for more info

Regards