Brake Issue! Help Needed

I have 16 Sport 4x4. I had my brake master cylinder go bad. I would brake and the pedal would just keep going to the floor. I replaced the master cylinder and bleed the brakes 4 times. The issue that I am getting now is that my brake peddle will go almost all the way down to the floor every 5 or 6 times of pressing it. All the other times it works fine. I don't think it the master cylinder is bad because even when it goes down it gets to a certain point it stops and does not keep going. what could be the issue or what do I need to do?

 

Did you bench bleed the new master cylinder before you installed it? Sounds like you still have an air pocket in the master cylinder itself.

 

did you bleed the brakes? could be air in the lines.

how is the fluid in the MC, still full?

 

yes I bench bleed the master cylinder before install. Fluid is still full. No leaks anywhere.

 

Did you check toyota.com to see if there were any recalls? I remember hearing about one:
https://news.pickuptrucks.com/2018/04/2017-toyota-tacoma-recall-alert.html

 

https://www.tacomaworld.com/threads...ng-for-dummies-me.602575/page-3#post-20277534

 

Make sure the caliper slide pins are not froze up. Happened to my Rav 4. I was ready to replace master. Piston would cock in caliper and create a soft pedal. replaced pads and freed up sliders. Has 200k on it and original master and rear brakes.

 

Ok so I just got my brakes bleed and having the same issue. Brakes work good every few presses then all of a sudden goes down and gets soft. Master cylinder was replaced and everything bleed properly. No air in the system. Anyone have this issue?

 

Factory Toyota master cylinder or OEM replacement cylinder?

 

replacement. toyota did not have a oem one and was not sure how long it would take to get

 

Replacement master cylinders are like replacement steering racks you need to install four or five before you get one good one it’s probably a Dorman product real piece of shit. Go on EBay or local boneyard and get a used oem one for $65 or less and be happy good luck

 

Like @Ronzio said. I would suspect a dud m/c. A friend saw this with a dead nuts simple caliper for his Bronco. The piston was seized in the bore right out of the box.

 

When u did the bleed job did u wait for the brake fluid to settle before attempting to bleed again . If not sounds like u have air in the lines . You might need to take it to a shop to have them run a pneumatic bleed system to get all the air out of the lines .

 

This is what they just did