AngelFJ

Let me get straight to the point, i suspect a bad master cylinder but let me explain my situation and i am looking for advice as to what to look for apart from that. 2002, 243k miles. About a week ago the red brake light would come on when i would hit the brakes and it would disappear when i let go, fluid had dropped a good amount so i assume its a leak. I planned on bleeding on the weekend. Comes Friday and as I'm going home, all the dash lights come on and a constant beep. Brakes worked fine for the first min but when i pulled over, they had lost all pressure. Fluid this time was actually maxed out so there is definitely some weird leak situation going on. I got home as safely as possible and the pressure came back (dash and sound still on) for a minute then left again. I'm pretty sure it's leak/master cylinder related but could it be something else? Abs? Switch? Any input is greatly appreciated, thank you!

Harold57

Just for reference, what year SC430 do you have?

Do you have access to a Techstream or an OBDII code reader? If so, read the fault codes being generated.

AngelFJ

2002, no codes come up when i plug obd-2 scanner

DshngDaryl

Yes,that makes sense. I believe it is a Lexus/Toyota specific code. I think your diagnosis of a bad master cylinder is very likely. Especially the beeping part. Very few things in our car beeps and that is one of them.

Google "clublexus sc430 master cylinder" and you can get some options. A new MC is very pricey. Lexus sells a rebuild kit. Other people call junkyards and sometimes get a used one for the price of a MC for a "normal" car.

GmanSC

Classic case of failed MC.