Brake mystery

[Juamgv]

Hey guys!
I bought a 2009 Tahoe Z71 and on my way home realized that needed new brakes. After a month I can't get the truck to brake properly. I will start to numerate what I have done, so you guys can help me to troubleshoot it:
1. Installed new brakes calipers (since 2 had rusted/stuck pistons), thinking it will be the main cause of not braking properly.
2. New brake pads and bleed all old fluid.
3. New hoses (2 front and 4 rear ones) since the fluid was contaminated with small old rubber particles.
4. Pressured air cleaned brake metal lines.
5. New front hubs (came with new abs sensors).
6. All four shocks and coils (for z71).

Everything was good until I turned it on and bleed it, the issue persists... I press the brake and goes all the way down to the floor. At this point no abs light or stabilitrack light on. Next steps:

1. Replaced MC with new one
2. Replaced booster with new one
Issue persists...
Removed EBCM and cleaned it, just in case old fluid clogged it.
Did the bleed again (both, with the scanner and old school way) recovered a little of resistance on the pedal but still takes 3 to 4 pumps to fully stop at low speed.

Lastly... getting back to the garage after testing it the code C0131 popped and both ABS and stabilitrack light are on and seems to stay there forever.

I will appreciate your help!!!

 

[B-train]

Are you sure the system wasn't contaminated with something other than brake fluid? I've witnessed this happen, and did all the repairs. It ruins everything from the MC to the end (calipers/brake cylinders). Everything had to be replaced, ABS and all.

I only ask/mention this because you mentioned small rubber particles in the fluid, and no luck adrer tunnjg throuh the bleeding process. If that's truly the case, you will be replacing everything......again. How did the master cylinder look? Can you see rhe cups - look for swelling and weird fitment/not symmetrical shapes. Same with brake calipers. Basically anything that was in contact with brake fluid and then ANY oil will be F'd and look weird after exposure.

 

[Dustin Jackson]

@Juamgv I'd say you still have air in your lines, it can be hard to bleed it all out. Did you install the new calipers with the bleeder zerk on top? Sometimes people get them on the wrong side making it so they don't bleed properly

 

[Juamgv]

Thank you guys for the info!
@B-TRA everything was removed and new parts installed, the only thing left from original setup are the metal lines, which I cleaned with pressured air from MC all the way back to the rear ones. MC looks good, the piston, the seals and the reservoir, I changed just to be 200% sure it was not it.

@Dustin Jackson you made me check for this one lol. They are with the zerk at the bottom, should they be facing top?

Now I have a question, why with the old components the ABS and stabilitrak light were off?

 

[Fless]

Thank you guys for the info!
@B-TRA everything was removed and new parts installed, the only thing left from original setup are the metal lines, which I cleaned with pressured air from MC all the way back to the rear ones. MC looks good, the piston, the seals and the reservoir, I changed just to be 200% sure it was not it.

@Dustin Jackson you made me check for this one lol. They are with the zerk at the bottom, should they be facing top?

Now I have a question, why with the old components the ABS and stabilitrak light were off?

Tagging @B-train since he wasn't....

They're not zerks, they're bleeders. And they should be oriented up, not down, in order for the air to be pushed out of the lines and calipers when bleeding. Swap those calipers side to side.

 

[donjetman]

you made me check for this one lol. They are with the zerk at the bottom, should they be facing top?

UP

2x what @Fless said

 

[89Suburban]

t-i-t-s up!!!!!

 

[rdezs]

I'm assuming you did a bench bleed on the master cylinder? And used a Tech 2 or similar device to bleed the ABS?

I always pressure bleed the system. Much faster and more effective.

And yeah, the bleeders point up.... If you have them down you have a whole bunch of air in each caliper.

 

[j91z28d1]

@Juamgv I'd say you still have air in your lines, it can be hard to bleed it all out. Did you install the new calipers with the bleeder zerk on top? Sometimes people get them on the wrong side making it so they don't bleed properly

nailed it

 

[Dustin Jackson]

I know this because even with the calipers on the correct side they can be a pain to bleed