craneauto Posted April 25, 2009 Share Posted April 25, 2009 Just replaced LS430 brake master cylinder. During the procedure, 2 brake lines has to be removed from master cylinder to ABS Solenoid. After install the master, I bleed the master and got some air out of it. Then I bleed all 4 wheels over 30 times. Just don't seem to get air out of the system. At the first pedal pump, the pedal is slightly low and 80% firm. Second pump, pedal rise up and 90% firm. Any suggestion ? Quote Link to comment Share on other sites More sharing options...
17LexusOwner Posted April 25, 2009 Share Posted April 25, 2009 My suggestion is your pedal is fine. Have you even tried driving it around yet? It's a luxury sedan, it doesn't have a stiff pedal like a ricer, you're sposed to be able to smoothly put on the brakes. Quote Link to comment Share on other sites More sharing options...
SRK Posted April 25, 2009 Share Posted April 25, 2009 If the pedal pumps up, it is NOT fine. By bleeding through to the wheels you have introduced air into the entire system. The master should have been bench bled, and then bled at the pipes leading to the ABS unit only. That would have prevented air migrating in the system. Try bleeding at the ABS and master cylinder lines only now. The air may move vertically in the system and end up at the highest point, the MC. I've installed hundreds of master cylinders, new and rebuilt, and never pulled a wheel. Quote Link to comment Share on other sites More sharing options...
17LexusOwner Posted April 25, 2009 Share Posted April 25, 2009 When your replacing a MC you should always bench bleed it, fill it back up, bleed it a little again to be sure, and install it. Then bleed all the lines (2 or 4) to make sure that the system didn't get any air in it while you had the MC off... And as far as the pedal pumping up, i'm pretty sure he's talking about having the car off and then pushing the pedal. If he is talking about that then the pedal always gets harder to push down because the pressure builds up and you have no power brakes. now if it's getting tougher while the cars driving and your stopping is getting choppy than that's another story. Quote Link to comment Share on other sites More sharing options...
craneauto Posted April 25, 2009 Author Share Posted April 25, 2009 I did bench bleed the MC and then bleed it again before tightening the 2 lines. I don't really want to take out the MC again. So can I remove one line from the MC and bleed it and then do the second line ? Like SRK says maybe I have already push some air into the system, how much bleeding will it take to get the air out of the system ? Already done 30 pumps each wheel. Quote Link to comment Share on other sites More sharing options...
17LexusOwner Posted April 25, 2009 Share Posted April 25, 2009 Umm just bleed each wheel starting with the passenger rear wheel and then move onto the driver rear, passenger front, and driver front. Make sure to bleed each wheel until only fluid comes out. (helps a lot if you got a buddy to watch while you pump, so get a case of beer or something) Also it might help to get fresh brake fluid and flush the entire system and replace all the old stuff. Quote Link to comment Share on other sites More sharing options...
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