Brake fluid taking on air

I'm working on my fathers second gen Tacoma its a 2005 4x4 with a 1GR-FE. I replaced 2 of the brake lines that had been rusted and leaking I also replaced the master cylinder. I just cant get the pedal feel to be consistent I've been over all the brake lines there no leaks. I've bled the lines like a thousand times but even when I made progress the system would just take on air again and not hold a good brake pedal feel. Is it possible for air to get into the system without fluid leaking out? I used a fitting on one of my brake lines that I think may not have been a perfect fit even though it doesn't leak and felt like a good fit is it possible air could be entering through there somehow? I had also questioned if air could be entering around the front bleeder screws because on one of the front calipers I had a series of bubbles come out that was definitely greater than the volume of the brake system. I cant find a leak anywhere and even driving it and watching the fluid level I don't seem to be losing any fluid at all. Thank you all in advance for any help you can offer.

 

If there’s no leak. the system can not get air in it. There must be some air still in the lines from opening up the system.

 

but if that was the case how would I be able to make it better only for it to get worse again is it possible for air to bleed in without fluid bleeding out?

 

Did you use the required computer thingy to bleed the ABS system or did you do it old school?

If brake fluid isn't leaking it's not taking in "new" air.

 

Yup, gotta have somebody with the proper laptop bleed it due to the ABS system.

 

I work at a toyota dealership I could easily do that is that something i would have to do since i replaced a line into the ABS module?

 

Yes. If you removed a line from the abs module you probably have air in the module that needs to be removed. That’s were I’d start.

 

Some folks get away with doing brake work on Tacomas (with or without opening the system) and have no problems. Others - even when they don't open the system - need to get the "laptop bleed." I wish I knew why.

 

I linked up the Tacoma to a scan tool and used Toyota techstream to try to bleed the abs but the program told me that function isn't available on the 2005 is there anything else I can try to get the air out I have monitored the fluid level and its not leaking at all so it has to just be trapped air.

 

Man, I'm stumped. Have you asked a Toyota Certified Technician? I know folks love to hate dealerships, but the techs do work on Toyotas every single day. Chances are, they've seen your problem.

 

It's not a *GREAT* solution but I had some success getting up to 30mph on a dirt/gravel road and locking up the brakes repeatedly then quickly two man bleeding or using speed bleeders to bleed the system. By locking it up you get the ABS block system to pulse and it can force some air out over time.

Another solution is to have something manually keeping firm pressure on the brake pedal over night, a spreading clap or the like against the seat or steering wheel, keeping pressure on the fluid can help to suspend air into the fluid in micro bubbles that can then more easily be carried with the fluid when bleeding but this is only of the ABS block isn't bypassed when not under ABS conditions.

I have a hard time believing that ABS Control is not available on your 2005 when my 2000 had it, I suspect the tech is not performing the order of operations correctly and I would take it into a shop that has experience in this.

I had to take mine to a Mom-N-Pop-Shop as even my local dealer was too incompetent to bleed the ABS block with the solenoid activation, they kept just doing a normal bleed.

One last solution that's possible is if you have a TRD off-road with A-TRAC if not don't worry about it.

Last consideration, the brake fluid reservoir is a two stage reservoir and it's possible to have fluid in one half that you can see and be sucking air in the other half that you can't, never let the reservoir get under 3/4 when bleeding.

And if you haven't already invest in speed bleeders and a bleeder bottle even if you make your own it's a game changer.

There's also a tutorial on her for a "Street elbow and sink reducer" "power bleeder" on here that can help a lot but will get you in trouble quick if you use too much pressure or aren't paying attention.

 

Somehow I get the felling you're not a dealer tech, but being employed there, you might be able to get one to help you with this problem.
For what's it's worth, I am uploading bleed info for 2 different types of systems - those with and those without VSC - vehicle stability control.
There's no mention of techstream on the "without" version. There is mention of an "intelligence tester" for those with VSC. The intelligence tester is not techstream.

 

Did you bench bleed the new MC?

 

X2

Edit: if the master was not bled before install and has air remaining inside, you will never have good pedal feel.