I must start by saying that it's a relief to finally find a lexus Forum where people have an understanding and appreciation for the automobile. While lexus is a great car, this particular model is driving me nuts ! so here it goes...
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. changed all rotors and brake pads.
2. changed the brake master cylinder.
3. checked all the callipers and the lines for leaks.

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 ideas/advice would be greatly appreciated.
I can be reached at assumption01@hotmail.com.
Al.

 

lexs400,

sorry to hear of your trouble. from my limited knowledge, it sounds like a hydraulics problem, but it sounds like all of that has been replaced. perhaps a moderator could move this to the maintenance forum where it could get more visibility from the people with deep experience that hang out over there?

good luck

GA400

 

Yes, it's not normal! Take your car to another place and do a complete brake fluid flush and change. It sounds like you got a bad air contamination in the system. Fluid change should not cost more $100. If this doesn't help, check your brake booster/servo unit.

 

when it irratic and sometimes spongy its normally due to air in the system. How did the air get in there? there are a few suspects. Your bleeder nut has come loose on one of your calipers or you may have a break on your brake line. Check your brake lines and if they are torn replace them with (stainless steel braided brake lines(available aftermarket vendors)). This will last you longer. You als need to bleed the system. You need 2 people for this. or you can take it to a mechanic. They are your brakes so be certain that you know full well whats involved with the process or go to a trusted mechanic.

 

Gentlemen,
Thanks for the prompt replies. It definitely helps to have another persons' opinion on this matter.
Given the fact that I had posted this after I had picked up the car from the dealer yesterday, I called them again to raise the questions/concerns that were brought up. and here's what I was told :
1. Given that the master cylinder was replaced, the brake fluid had to be flushed.
2. The brake callipers were checked for bent needles, and also greased to ensure proper function.
3. The brake lines were checked for cracks or leaks and none were found.

So that to me sounds like they've done everything that we could think of. And the problem is still there. Now what ? ....

 

power brake booster? ABS mechanism? don't know what else could be wrong...

 

Your car is not safe to drive. Please take it to another shop! Very often, a shop will refuse to admid wrong doing because it costs them time, money, and their face. Lexus dealers are usually good and much better than others but it doesn't mean that they don't screw up things. It happened to me twice and I am sorry to say that your case is another example.
Saying that it's normal for your model year is just BS.
Very likely, another shop will bleed your system and go from there. The last thing that could go wrong is the brake booster (they have not change this right?) but do the bleeding first because it's a cheap test.

 

lexs400,

I would encourage to write down dates and names while it is fresh in your mind. Maybe call Lexus corporate (see contact numbers on Club Lexus front page) and ask them to recommend another dealer near you? After another shop fixes your brake problem, I would strongly encourage you to give the original dealership one more chance to refund your money (too bad they can't pay back the time you have wasted), involve Lexus corporate and, if necessary, your local better business bureau. This is NOT normal behavior and I hate to hear about you getting the run-around.

GA400

 

You're right.
I'm going to a private shop tomorrow because they acknowledge the fact the the pedal is a little too spongy and the brake response is not normal. Which is a good start since they see this as a problem.
I will let u guys know how it turns out.
I guess it's bleeding the sysmtem again, and if not that then as VSsc pointed out, either the brake booster or abs.
I havent had any problems with the abs so probably the brake booster is next.
Thanks again for everyone's input on this.
As for reporting this to Lexus, once I get this problem fixed I will definitely make some heads turn in the corporate office. !

 

Allright Guys, here's the latest.
The mech at the private shop did a much better job than the dealers. He bled the system and found air in it. He also adjusted the height of the pedal. So the breakes are much better than they were before. It just bothers my why the dealers couldn't do the same job.
The problem that is left at this point is : every now and then the brake pedal seems to require a lot more force than usuall to do the stopping. It's as if the power booster does only half the job and I'm required to do the rest.
but a minute after the brakes would go back to normal.
Does this mean I will have to change the power booster now ? if so, what is the cost that I'm looking at ? or is there something else I should try changing / getting done before hands ?
Thanks again. !

 

I am glad that they found air in your system! You should ask the shop to tell you what is your problem now. Yes, it could be either the booster and/or the master cylinder! None of us can tell you anything more without actually driving the car.

Since Lexus got an incompetent mechanic that worked on your car, he/she could possibly screwed up on replacing your master cylinder also, who knows?

The fact that Lexus got to change that many brake parts to find a problem - sorry, still not find your problem, scares me. All I can say it that you got screwed big time. A competent mechanic can pinpoint your problem with one single diagnostic. Brake system is not that complicate. Good luck.

 

Another question regarding the ongoing problem solving dilemma,
I've had the brake fluid flushed, but that didn't help the spongy pedal.
I however have noticed now that intermittently, I get the perfect pedal with perfect braking distance.. It happes perhaps two to three times a day at different times but then goes back to the spongy pedal with ineffective brakes with poor braking distance.
My question : what part of the braking system would cause spongy pedal but intermittently have a perfect pedal as well.
Could the callipers have anything to do with this ? The dealer has already lubricated all the callipers and checked for their proper function.
I'd appreciate anymore insight to this. For a change I'd appreciate more responses than I've had in the past on this problem.
thanks.

 

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.

 

It is my guess that the Lexus tech din't properly bench bleed the new master cylinder prior to installation. You will never get your brakes right if this isn't done correctly. Normal bleeding will not remove all the air trapped in the master cylinder no matter how many times you do it. The other, by very remote, possiblity is that the new master cylinder was defective. Things happen..

If your booster is bad, you will have to push with all your strength to stop the car. Luckily, they are fairly easy to replace and sometimes you can find them in junkyards fairly cheap (<$25). First you have to find a junkyard with a Lexus in it. A difficult task at best.

 

got a call back from the dealer today. it's unbelievable. the service assist manager had test driven the car with me last week and acknowledged that the brakes werent as effective. now I get a call today from the manager of service saying the tech's checked it out again and don't see any problems. I wasted half an hour trying to reason with him but he won't listen. As a last resort I did tell him that I almost got into an accident situation and want to take this all the way upto corporate lexus and he said I'm welcome to do that...
They claim they checked the system but I know they didn't since their assist manager told me they don't do anything besides test driving the car and checking for leaks of brake fluid.
The master cylinder was replaced last year by them. When I told them that other techs have pointed out to a possilby faulty master cylinder he said it didn't show signs of any problems.
I'm stuck and quite frustrated.
what should I do next ?
I would like to know what other compnonents could possibly be at fault here. the following have been replaced so far :
1. master cylinder
2. brake booster
3. brake pads and rotors
4. Calllipers have been checked for proper operation.
5. bleeding done 5 times by different mechanics
6. pressuer check valve

Anything else that comes to mind ?
symptoms are :
spongy pedal,
never touches the floor but stops about 2 inches away from it.
requires additional foot force to stop the car. the more foot pressure is applied to the pedal, the harder the pedal seems to get, it's as if the pedal is resisting the foot pressure while I'm trying to brake.

I'm in new jersey, and would be more than happy to take it to anyone at this point who specializes in brakes. I just need the damn problem fixed. but before I do that, I want to make sure that the $2750 that i've given the lex dealer for the same problem don't go wasted either...