Bled brakes twice, pedal still falling...

[cool breeze]

I did a full brake fluid flush recently and now have a falling brake pedal. Once the truck comes to a stop if more pressure is applied the pedal will go down quite a bit more until it stops but does not hit the floor.

Ive bled the brakes and lspv twice the old fashioned way with a helper and still no better. I did remove the fluid resevior to clean it out if that matters.

What do i try next?

 

[Skillet]

Did you bleed the MC?

If you completely drained the reservoir you need to bleed the MC.

I made this mistake once.

It is a bitch with one person but I have done it three times.

Read the FSM for the exact procedure.

 

[inkpot]

Howdy! As per Skillet, try bleeding the MC. If that does not help, then the MC is probably becoming corroded inside, and the seals are leaking down as they pass by the flaws in the bore. Time for a new MC. SOMETIMES they can be rebuilt and/or honed out as a repair, but it is not really worth it. Usually it will be doomed to fail again, soon. John

 

[thestallionq8]

I had a problem with my brakes and I had to change the brake booster!

 

[cool breeze]

I hope i dont need a new one, ill try this today. Do i need to bleed the brakes again after I do the MC?

 

[landtank]

I just went through something similar. It turned out to be bad SS brake lines. They were letting air into the system but not leaking any fluid.

One of the tell tale signs was that after a full pedals push and bleeding a caliper, on the next push the pedal would travel near the floor before there was any resistance. It had sucked air back in the system when you let your foot off the pedal.

I also tried the MC and have it in the for sale section right now as it wasn't the problem.

And you should bench bleed the MC and then you will need to bleed the entire system again as well.

 

[cool breeze]

Well update time:
Forgot to mention in the beginning when i removed the MC i also installed a rebuild kit(plungers) from toyota. Bench bled after suggested here..bled brakes, once, twice, three times using over two quarts of fluid.
Switched to new SS brake lines which i needed any way for lift but didnt help.
Checked rear drums to see if adjusted or sticking and were fine.
Finally after a year or so driving around with what i would now call half-brakes I had a 3k mile road trip coming up in which family was going to be riding in the car. Going to CO where mountains rule and dirt paths everywhere with precarious drop-offs I didnt want my brakes to be like this so i took it to a highly recommended shop here in SA.
Replaced MC with an aftermarket(not enough time for aisin but its only a single piston right, make me feel okay about this )

NOW I HAVE BRAKES!!
Im really impressed with how well the stop for such an older vehicle loaded down. Next pad change will be an upgrade to something more aggressive.

CLIFFS: toyota MC rebuild kit = worthless. After going through everyone elses problems it looks like new is the only way to go.