GS4_Fiend

iTrader: (22)

Looks looks like on our cars we cant manually bleed the master cylinder like other cars

streetz

Yeah, I spoke with a master tech at lexus and told me exacly that. You cant manually bleed it. just install it, pump 40 times, etc... pretty much what these instructions said.

toy4life86

iTrader: (4)

its a pain in the *** man but after like 4 containers i had finally got mine bleed properly i actually had to open the line at the master cylinder and then bleed from there first

streetz

Damn, do you remember which line? How did you bleed it? You left it loose so when u depress brake it leaks the air?

GS4_Fiend

iTrader: (22)

That's how you bleed the Master Cylinder on other cars too. Lexus works the same way?

streetz

So i put in the new unit, put some fluid, pumped 40 times, also while at it, bleed it via the two front lines (which leads to the front brakes), no more air came out just fluid, so good.

Then turn IGN on, pumped 20 times + and the beeeeeeep does not go away!
I can hear the actuator turn on every 5 seconds or so, then off, non stop. I do not know what to do at this point. I tried to reset ECU (pulling certain fuses and waiting a minute) and still nothing.

99 GS3

iTrader: (14)

Well reseting the ECU doesn't have anything to do with the brakes. The ABS/TRC/VSC module is seperate and controls the master cylinder you would need to reset that. I usually pull the negative lead off the battery for a few minutes, that will reset everything. (although it will reset your seat prepositions and radio stations as well)

I just finished a big brake swap front and rear a couple weeks ago and had to deal with this, it is a pain. I had the same problem as you at one point with the abs priming on and off when it isn't supposed to, it turned out there was still air in the system and it just wasn't blead enough..

These are the steps I used and it worked out fine, the brakes work great..

Do the 40 pumps, and turn the car on to let it prime then stop, then turn the key off. Then bleed the fronts like a normal car first, with the key off, RF then LF. (well a normal car is not RF/LF first, but normal as in just push and hold a couple times while someone bleeds the caliper a few times)

Then do the 40 pumps again, turn the key on acc let it run til it stops, leave the key on this time, then crack the bleeder RR and hold the brake pedal down til there are no bubbles and tighten, then do LR. No need to pump up and hold for the rears, the abs pump continues to try to build pressure and is pumping fluid down and out the rear.

Keep the cap tightened on the reservoir while doing the rear. And make sure it has fluid constantly, I used to 2 whole can's of ATE Super Blue to get all four brakes working properly and the abs to stop priming when it wasn't supposed to.

I tried to use a vacuum pump at the calipers like I do most other cars when I bleed brakes and clutches but it was a no-go on the GS.

streetz

Thank You very much for your input, it is very useful.

After doing some reading, I reset the ECU and all warnings went away, the brakes finally started working. I moved the car slowly and it was working. I also bleed the system at the master cylinder ports. No warnings, only got warnings when I would pump to about 20 with ign on, so its maybe due to a little air in the system. Tomorrow once rain goes away I shall finish bleeding the corners and call it a day. Thanks for the help yall.

GS4_Fiend

iTrader: (22)

interesting how you guys bleed the fronts first instead of the rears. I did rears first then fronts and my system is air tight.

streetz

I do not think it matters whether you do front or back first, there might be a reason alot of folks do the fronts first thought.

GS4_Fiend

iTrader: (22)

Well bleeding rears first is what the majority people would do. If you search about bleeding brakes, I would say 9/10 would say bleed rear first. I'm not trying to start a controversy, but just saying. If it works for u then kool.

toy4life86

iTrader: (4)

I also did the fronts first... but after that was doing back fronts there was alot of air in there, also I even used a vacuum to bleed. But what I do remember I was having an issue with 2 calipers one front pass side and one rear. So I also replaced those. Now that I think of it my master cylinder may not even had been bad it may have been my calipers. Because the pedal was soft but brakes still worked but now they are much better.

99 GS3

iTrader: (14)

Yeah all cars with standard vacuum booster master cylinders you bleed from the RR first (or the longest routed line)

Nobody is trying to reinvent the wheel here I'm only going by what the Lexus Factory Service Manual states the procedure is, and that is to do the fronts first. It's something to do with the way the Electronic Master Cylinder/ABS Module works.

The FSM actually doesn't tell you how to do it without either the Mastertech Computer or the SST.. Those devices enable an "Air Bleed Mode" in the Master Cylinder to bleed the brakes. That is where trying to do it otherwise "manually" can be a hassle.

Holding down the brakes for the rear is a way to have the abs pump to stay open and push fluid thru, which is similar to what air bleed mode does. But the fronts are not affected in the same way by the system, so for what ever reason since fronts are 'standard' in a sense they state to bleed those first.

It's really only an issue when removing the master cylinder as the OP had done, or like when I had to do it because of swapping all 4 calipers and lines, and also completely exchanged 100% of the fluid in the system all at the same time so the entire system was dry.

So typically when just bleeding the brakes, pushing through new replacement fluid without draining it, or swapping just front calipers, then all this is likely not needed and just a pump/hold/bleed like normal is fine.

streetz

Ok, it looks like success yall! I did the 40 pumps, key on till it stopped priming, key off, bleed front. Then pump again 40, key on and left on, pump and hold, bleed rears. Had minimal air.
Thanks for the help of everyone!

One last thing, as for the fluid level, I understand you have to pump 40 times in order to properly measure or fill. Does this mean that during normal operation the fluid will be below the Max line? (after 40 pumps it goes to the max line)

https://lh6.googleusercontent.com/-i...2/IMAG0335.jpg

99 GS3

iTrader: (14)

I'm glad the same steps worked out for you.

Yes, it may be below the max normally. Do the 40 pumps and check/add fluid like is printed on top the reservoir. If you just fill to max without pumping then it may overflow out from under the cap once pressurized.