A little help please

hello everyone. I have a 2002 tundra sr5 and i am having an issue with the brakes. I have replaced the master cylinder, booster, calipers, and wheel cylinders. I have bled the system completely but the brake peddle feels weird . The brakes work but when i step on the brake peddle it kinda goes down too far and does not feel normal . it almost feels like there is a leak but there is not. With the engine off the brake pedal feels nice and firm but when it is running the pedal slowly goes almost to the floor with a hiss. any ideas ? thanks.

 

Could be air still present.

 

Sounds like its not fully bled. There is another post here about someone with a similar problem.

 

@Professional Hand Model @because_v8 @Casper421 @Darkness

 

This one?
https://www.tundras.com/threads/bleeding-brakes.41230/#post-1051875

 

Yup. Sounds like the same issue. Fixed by having the dealership bleeding the system. I following these brake threads closely as my front rotors are warped and I want to do the caliper conversion when I fix them.

 

Did you bleed the brake proportion valve in the rear?

Also, one thing I've never tried is bleeding the actual master cylinder. There is a bleeder on it but I've never seen mention of using it. Since you've opened the whole system up that may be worth a try, it's a high point where I could imagine air getting trapped.

 

All of this.

 

My fix in that other thread was actually having the rear brakes adjusted. I had the adjuster in all the way so the rears weren't catching.

 

Unless the master cylinder fluid level had gotten too low there wouldn't be any air in it. Brake systems are different in that the air won't migrate to the highest point it has to be forced out through a bleeder.

OP did you bench bleed the master before installing it? That would be a concern because the will hold a lot of air if you don't.

 

He replaced everything, that's why I would consider bleeding the master.