Hey folks, I'm kinda at the end of my rope and i figured I'd ask yall before just bypass stuff. Here's whats going on.

Got my 97 SC400 almost a year ago. 200k on the clock but very well maintained, everything works, all services done at a toyota dealer by the schedule. Hell, most of the parts under the car have bar code stickers on em. When i got it the brakes were a problem. No leaks, the car stops fine, but after you've come to a stop the pedal would slowly go to the floor. I bled them several times with no real success. It would sometimes feel like things got better after bleeding, but the problem remained. I eventually put a master cylinder in it. Some oriley's one, forget the brand. That felt like it got it for a couple days, but then it started to lose pressure again. Bled it again with no change. Thats where I'm at.

I was wanting to ask yall about bleeding the abs system. The abs actuator has a bleed screw, but it doesnt seem to do anything. I read online to keep the tires off the ground and let the rears spin to engage the abs/trac pump and then bleed everything but I'm either doing it wrong or its not helping.

Does anybody know the exact way to bleed everything including the abs pump/actuator? I wanna know how Lexus says to do it. I just wanna try everything before I just bypass the damn thing.

Thanks!

 

The new master cylinder could have a manufacturing defect. I once put an Autozone clutch master cylinder in a car and had completely failure within 90 days so I learned by lesson to go OEM on such critical stuff. My theory is that when they rebuild master cylinders they are off by a fraction of a millimeter when it comes to internal seal measurements. Since you just bought your brake master cylinder they should just swap one out under warranty. If you install the new one and have good brakes you will know that was the problem. Even if it fixes your problem I would say buy a new OEM master cylinder since the brakes are not the part of the car to save money on.

If the brakes are still bad then the ABS modulator can be the problem if it has internal leaks. Years ago I had total brake failure in my 98 SC300 and hit another car at low speed. Bosch manufactured the modulator and they are known to go bad around 20+ years in multiple makes and models of cars. When I had my failure Toyota had discontinued the part so I had to reluctantly put a used one in and it fixed the problem. Toyota brought back the part later but as of today I am not sure if you can buy a new one.

 

Yea, might as well try another one. I'll do that before bypassing it.

Does anybody have the procedure for bleeding the abs modulator?

 

There’s an Advics master cylinder through RockAuto for $137. Advics is the OE supplier for Lexus’ brake components today. I’d give that one a go. I only ever buy OE manufacturers like Advics, Aisin, Denso, etc etc…if it’s not from a big boy like them, it’s not ever worth installing.

Nick

 

Sure sounds like master cylinder again. There is a procedure for bleeding the abs system in the Lexus manual but I can't find the pdf file now. Too many lost computer hard drives I guess. But I can say, with all of the brake system work I have done on these cars I have never had to do it.