My brain is melted and I'm running around in circles like a dog trying to catch his tail. What started out as a brake overhaul turned into a total brake system rebuild. I started with new pads, rotors, calipers and brake lines all the way round. Bled the entire system and couldn't get a stiff pedal. So with 121000 on the od I replaced the Master cylinder with a new oe. Bled the entire system again, still no @#$#@ pedal!! Bled this thing every way possible with no luck. Performed component test and narrowed it to the Hydroboost. Replaced with new oe. Ran about another gallon of brake fluid thru the system. NO PEDAL !!! There is NO air or leaks in the system. Never a problem with brakes before this jus the normal maintenance stuff. pads, rotors. They were no issues with system before this. Jus worn out pads. The pedal goes to the floor very easy no matter what i do. HELP!! I have Autoenginuity diagnostic software. There's no DTCs or cel, nothing. Never had this much trouble with brake job. What am i overlooking or not doing??

 

I know when we have lifted trucks and done new lines it has taken a while to bleed air. Just to be sure, you did bleed at each caliper?

 

Yes, I bench bled the master, more than once, and then each caliper in proper order, more than once. I've pressure bled at 15 psi, more than once, and also used the wife for pump and hold bleeding. I get that this was going to be somewhat of a challenge to get all the air out but this is ridiculous! Is it possible that i still have air trapped in there somewhere? During all the bleeding processes I did make note that the flow of fluid/air from each component was without restriction. However the flow never comes shooting out like a pressure washer its more of a controlled steady slow stream. Thank you for your help!

 

It sounds like there could still be air somewhere or maybe somethings wrong with the new master? I'm surprised you had to replace the master cylinder at 121k. We always did the 2 person bleed, until the fluid shot out of each caliper.

 

New master is good. Confirmed by component test. Removed the lines, blocked off outlets, depress pedal. Firm, no leak down. Is there some valve or senor or something to be turned on/off, open/closed or something in the abs thru the dlc with Autoenginuity?? Recalibrate the hcu??

 

Ok, deep breath & relax.......yes, assuming all the components are good, there is air in the system.....sometimes tiny air bubbles can be a living PITA!!!! and the only way to get them out is with a "pressure bleeder"....sometimes the small hand-held little guys work but, what is typically required is a true commercial/professional type unit that has a fluid reserve in it....and sometimes it can take days, including reverse bleeding to get em out.

 

I'm cool just frustrated. In serious need of some useful insight. I'm using a Motive pressure bleeder with a 2qt reserve tank pressurized to 15psi.

 

Yeah, that's really not much different than having someone pump the pedal for you...it works except when you have a bubble that's floating in the system. While I am not promoting this product (and I don't know anything about this mfg specifically), here is what a true professional shop will have.....

Pressure Brake Bleeder at National Tool Warehouse

Don't feel bad about having to possibly take it to a "professional shop"....my dad (aka fonzie---really) whose engines were very well known, turning up to 211 mph in the mid 50's at El Mirage, had a car in the 60's IIRR, he did a brake job on it, bled the brakes for days, could not get the bubble out....ended up taking to a local garage (knew the mechanic there), who said, no problem, I'll call ya when it's done...........3 days later he got it........never had a problem before of after with that car.

 

If the consensus suggests there is still air in the system I can accept and resolve the issue with my "unprofessional" tools and equipment. This is my first experience with major repair on an hydroboost assisted brake system. In the few hundred brake services I have performed successfully, this is the most stubborn by far. I just needed to step away from the job and get a outside assessment of the situation and my procedures to confirm that I'm not overlooking something and I'm not over diagnosing. The result of my efforts here on the forum has been successful in that I realize I mispoke when I stated that I have bled the system every way possible because I havent tried reverse bleeding. So this will be my next procedure. I would like to sincerely thank those of you who took the time to respond and help.

 

Are your bleeders on the top or bottom of the rear calipers?

 

They are on the bottom.

 

They need to be on top you have them reversed

 

You have done what I did!!!😛

 

The part store gave you two of the same side

 

THANK YOU T for insight/experience with a BIG hammer to my dum head! As soon as I read and answered your question I knew. The ultimate rookie mistake,(shame). I threw things together so fast and under a ton and a half of stress. That I didn't even notice! When things didn't work I was blinded even more by panic. Good grief!! Thank you Thank you Thank you!!! On the bright side, I guess, I have a totally rebuilt brake system and won't have to worry about that for a long while! Also thanks to all who took time and chimed in to help. That's why this is the best forum in the world hands down!! Great people and a massive wealth of experience.