I installed new front calipers and pads on a 1998 Lexus ES300. I keep getting plenty of air bubbles when I bleed the brakes. I am keeping the master cylinder filled, so I'm not sure where all of this air is coming from. The pedal keeps going to the floor. The booster is Ok. I'm thinking bad master cylinder. Ideas????.

thanks

 

How are you bleeding the brakes?

 

If the master was dry after replacing the calipers you should pre bleed the master... with the lines off have sombody SLOWLY push the pedal down then BEFORE they let up hold your fingers over the holes where the lines go and let up on the pedal... repeat this until no air comes out of the master... make sure you have rags and make sure your helper pushes the pedal SLOWLY

 

Thanks for the reply.

I didn't change the master cylinder so I kept it full and continued to fill while I was bleeding.

I am having the helping push the pedal all the way and hold, then open the bleed screw and close it when all the air escapes, release the pedal. Repeat that step as often as air comes out, but even after a constant flow of fluid, on the next pump, more air.

 

before you bleed you should rapidly pump brakes about 6 times then hold the pedal down then bleed and repeat until bubbles stop

 

The other thing to note is that you should always bleed the caliper that is farthest away from the master cylinder first then go to next furthest one.

 

Exactly. One other thing to note, if you dont clamp off the line somehow before you remove it from the caliper, the lines will be air-bound like a ***** and will take forever to bleed out