Brake pressure lost or not enough

I have a 2009 tacoma single cab 4 cylinder base model. My taco loses brake pressure when I brake or when im braking the truck has not enough braking power I get a sinking pedal, I have changed my master cylinder from dealer part and my calipers are new and new rotors and pads. Any ideas what it can be!! Can anyone help out thanks

 

Mmm have you checked all your vaccuum lines to see if you have a vaccuum leak?

 

Air in the system. How did you bleed the ABS System?

Make sure the rear shoes are properly adjusted. The procedure is posted in here somewhere.

I'd bet air in the system.

 

Also make sure you dont have leaks anywhere

 

Have done all that dealer has bleed the system with the scanner and manually and still the same

 

Your rubber brake hoses may need replacing because they are expanding when pressure is applied. Just a thought.

 

If a dealer has been doing the work, they need to fix their work.

Keep in mind a bad master out of the box is not impossible. Additionally sometimes dealers sell reman parts to have a lower price option.

I had a devil of a time bleeding an '04 Highlander, and Techstream was really needed to clear the ABS. You say they have done that, but it doesn't mean it was done correctly.

 

Well see I had 2 different dealers and and 3 different mechanic shops look at it and they cant find it

 

^^^^THIS^^^^

 

The dealer has not done anything my truck, all they have done was check it and say it was ok

 

Is it ok? If they said it and it wasn’t then that should be on them

You might need to have the ABS bleed through Techscan or whatever it’s called.

 

Ill be honest I had my abs bleed already with the scanner 4 times and its the same thing

 

Are you new to the truck? My pedal in my 2009 Regular cab 4cyl has always felt softer than most trucks/cars that I've driven. Are you not able "lock" up the brakes if you needed to? Or do they just feel like there is a lot of pedal travel?

 

brake booster

 

Correct my brake wont lock up when i brake hard

 

The booster never changed it out but it has pressure when i release the hose

 

sounds like your brake booster is bad/going out.

 

OP do you have a manual? check for leaks on the clutch master cylinder / slave cylinder as they use brake fluid as well from the brake master cylinder reservoir

 

No mine is automatic

 

Hmm, pull the vacuum booster vacuum hose and see if its oily. Maybe you are leaking fluid into there.