Brakes go down to floor - 1998 Lexus Gs 400

I use a vacuum pump to bleed lines stating pass rear drivers rear pass front then drivers front. ensure the the brake fluid reservoir never goes lo low, or you will introduce air into system. Purchase plenty of fluid and draw out all the old fluid. It will be replaced by new fluid. Sound like you have air in system

When you start the engine, the brake booster comes into play. Brakes to the floor indicate air is in the system, or master cylinder is bad.

Your brakes are probably worn down, and need new pads. Check the thickness of the rotors.

no year, no joy.!!!
what does brakes down mean
car stalls
or the foot brake falls to the floor boards?
breaks are not same word as brakes.

catastrophic failure , DO NOT DRIVE
so find leak, see leak location, that is BAD.
MC (master cylinder)
or slaves (calipers or drum cylinders.
or hoses. (any)
pipes, (aka, hard lines)
junctions.
aBS?

why not post source of leak, or better photos.
or better yet, call a mech. for help .

floor, floor of cab, floor of garage, just a tiny hint on floor
and what 4 corners of car. inside or outside.
,fluid can leak down both sides of any MC

usually an indicator of either a loss of pressure due to low fluid and/or air in the system (brake fluid leak) or extremely worn rear brakes (if drum brakes in rear). possible causes include master cylinder (internal fluid pressure leak), external fluid leaks (calipers, lines, wheel cylinders), rear drum brakes extremely worn down or severely out of adjustment. normally worn disc brakes may reduce pedal height SOME, but seldom "to floor". but the "mushy" quote combined with the "floor" quote suggests a hydrolic fluid pressure problem.

chances are the seal inside the master cylinder is blown (check for leaks before buying bits......)

The brakes just need to be bled properly which take 2 people or a bleeding pump,Please tell me how you are bleeding the brakes.

make sure brake fluid is full. then pump brakes for one minuite check the fluid to see if it went down or stayed full. if it went down then check the system for a leak . if it stays full then you will need a new mastercylender . i dont think you have a vacum problem cause this causes a verry stiff brake pedal not one that goes to the floor

You need to have the brakes bleed, there is air in the system, a special tool is required to bleed them, it holds the gate valves open in the ABS