philg Posted January 8, 2007 Posted January 8, 2007 The brakes on my wife's 98LS400 seems to be a bit too soft and mushy. We got the car about 1,000 miles ago and changed the brake fluid. When it went through inspection the mechanic did warn me that the brake booster may be near the end of its life as it was sqeaking intermitentily. When we first got the car I also noticed that the first 1/4 of pedal travel did not result in any braking action, since replacing the brake fluid that has reduced itself to the first 1/8 of pedal travel. When driving the car I notice that I push the pedal at least half way to 3/4 of the way down when making a slow gradual stop from 40mph or so. Is this normal?The pads and rotors were all within factory spec when the MD state inspection was done and I was told that they should have about 10-15k miles left on them before they need to be replaced. Does this sound like a problem with the booster or a more serious problem?
rick98ls400 Posted January 8, 2007 Posted January 8, 2007 Hello, I have the same issue with my 98. One tech said the master cylinder was bad, went to get it fixed, the other tech said it is fine (rotors and pads well within spec). Another dealer has checked out my brakes and said everything is fine and "that is the way they all are" . I have a hard time believing that. I don't like the brake feel at all. I could use some advice as well...
RCRFAN3 Posted January 8, 2007 Posted January 8, 2007 I also have a 98 LS and I'm a certified ASE brake tech and my pedal is the same. It just feels lower than it actually is.
philg Posted January 8, 2007 Author Posted January 8, 2007 What really bothers me in my wife's car is that there is literally no action for the top 1/8 of pedal travel and that it is VERY easy to get the pedal all the way down to the floor. Is that still normal?
blake918 Posted January 9, 2007 Posted January 9, 2007 The brakes on my '95 were extra mushy, and it turned out to be a failing master cylinder (that eventually broke while I was driving. Talk about a stress test. LOL). Mine was leaking where it mounts to the booster. I believe that the repair manual states how far the brake pedal should travel. Maybe someone with a '98 repair manual can post that info for you. I've grown accustomed to the mushy brakes in my car; it makes smooth stops much easier. When I most other cars, it feels like the brakes are either on or off. I guess it's all in what you get used to...
SKperformance Posted January 9, 2007 Posted January 9, 2007 I have to agree it is pretty muhsy. One contributing factor may be the calipers are larger and also have 4 pistons up front . This combined with the added pressure on the brake lines it will cause flex. I am trying to see if we can get the 95-00 model a set of braided Stainless Steel brake lines so that it will reduce the vague feeling. I have them on my other cars and the SS lines are the best for added pressure . Anyone ever notice that if you let go and press the pedal again real quickly the brakes will stiffen up 3-4 X more? Usually that is from either a bad proportioner , bad booster, or sticking brakes or mushy brake lines. Try it and post back.
cardona6569 Posted January 9, 2007 Posted January 9, 2007 I had the same problem, I even changed some of the rear pads myself and the problem kept about the same. That was so, until while inspecting the upper part of the engine, I found one of the air hoses cracked. Procedure, take the Lexus Plastic Cover the one with the 2 screws and 2 nuts, and check all the rubber hosing that goes to the brakes and all the related ones, if mine was cracked some of yours will be also, the hose that I had broken was a small one but it went towards the brake boosting area. Remember the engine has a lot of heat and the plastic cover do not help those hoses under it. CPR I have to agree it is pretty muhsy. One contributing factor may be the calipers are larger and also have 4 pistons up front . This combined with the added pressure on the brake lines it will cause flex. I am trying to see if we can get the 95-00 model a set of braided Stainless Steel brake lines so that it will reduce the vague feeling. I have them on my other cars and the SS lines are the best for added pressure . Anyone ever notice that if you let go and press the pedal again real quickly the brakes will stiffen up 3-4 X more? Usually that is from either a bad proportioner , bad booster, or sticking brakes or mushy brake lines. Try it and post back.
jakemt Posted January 10, 2007 Posted January 10, 2007 I had the same problem, I even changed some of the rear pads myself and the problem kept about the same. That was so, until while inspecting the upper part of the engine, I found one of the air hoses cracked. Procedure, take the Lexus Plastic Cover the one with the 2 screws and 2 nuts, and check all the rubber hosing that goes to the brakes and all the related ones, if mine was cracked some of yours will be also, the hose that I had broken was a small one but it went towards the brake boosting area. Remember the engine has a lot of heat and the plastic cover do not help those hoses under it. CPR I have to agree it is pretty muhsy. One contributing factor may be the calipers are larger and also have 4 pistons up front . This combined with the added pressure on the brake lines it will cause flex. I am trying to see if we can get the 95-00 model a set of braided Stainless Steel brake lines so that it will reduce the vague feeling. I have them on my other cars and the SS lines are the best for added pressure . Anyone ever notice that if you let go and press the pedal again real quickly the brakes will stiffen up 3-4 X more? Usually that is from either a bad proportioner , bad booster, or sticking brakes or mushy brake lines. Try it and post back. I have that same mushy feeling on my '00ls as well. Mine also travels down a bit before any actual breaking occurs. And this is with new breake pads. On my '94ls the breaks modulated a lot better because as more brake pressure was applied, it progressively slowed the car. It appears this is normal behavior for the 2nd gen ls400.
1999ls400 Posted January 20, 2007 Posted January 20, 2007 I just bought a '99 LS400 and the brakes do not respond as fast/sensitive as some other cars -- BMW is just the opposite. I was at first a little dissapointed at the brakes on the LS. I'm getting more used to it now but still the brakes do go down quite a bit before you can feel braking.
littlefield Posted February 1, 2007 Posted February 1, 2007 Hello, I have the same issue with my 98. One tech said the master cylinder was bad, went to get it fixed, the other tech said it is fine (rotors and pads well within spec). Another dealer has checked out my brakes and said everything is fine and "that is the way they all are" . I have a hard time believing that. I don't like the brake feel at all. I could use some advice as well... I have changed all of the pads and the master cylinder, bled the master cylinder and I cant get the rear brakes to bleed. I cant even get a drop to come out. I think I might need to bleed the traction system. Dont have a repair manual, and not sure where to bleed.
LScott400 Posted February 1, 2007 Posted February 1, 2007 You didn't mention if you bled the master cylinder prior to bleeding the remainder of the system. Bleeding instructions for brakes and TRAC on Pp. 2-4: checkandadj.pdf
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