Brake pedal to the floor?

[k.daddy1]

I have a 99 chevy 1500 truck. I replaced all the front end steering components to include the front brake calipers and rotors. I have bleed all the brakes starting at the RR wheel and working my way up to the LF wheel. No air bubbles are present in the line to the bleeder pot, but once I have bleed the brakes and let the truck set for 5 minutes or so, when I push the brake pedal it will go all the way to the floor. I can pump the pedal 3-4 times and it will build the pressure back but will not hold it. I have went around and bleed the system 3 times now, but wont clear up the soft pedal. What gives any help would be appreciated! Thanks ahead of time.

[lalo56]

You pumped your brakes while vehicle is off build the pressure back and still would not hold the pressure?

[lalo56]

Also have you checked to make sure your brake fluid is at proper level?

[Mean_Green_95]

I've heard of needing to cycle the abs pump to get the system to bleed properly. But IDK for sure. Is it a NBS or and OBS?

[k.daddy1]

The truck is not running and has new fluid in the reservoir. I have bleed one wheel top off the reservoir, bleed another, top off, so on. Talked to a guy at a local brake shop and said its possible the seals in the master cylinder are bad. The brakes were working fine before I replaced everything, but now won't keep any pressure on the pedal. There's no leaks front or back and no air bubbles in the fluid flowing through the tube. Has me stumped! Maybe 160k miles has worn out the master cylinder??? The Kaiser H. ABS box doesn't have a bleeder port on it, but also the ABS light is not on, so I don't think there is air in that system~could be wrong. Could it be bad (new)calipers or master cylinder??

[lalo56]

I had a master cylinder go bad on me and i always had to pump before it would break to build pressure, it wouldnt hold it. My guess if you have tried all that you have done, guessing its the master cylinder. Hope you get this resolved soon.

[k.daddy1]

Thanks for the input, I'll try the master cylinder after work and post results tomorrow.

[lalo56]

have you gotten it resolved?

[k.daddy1]

Got it fixed over the weekend. It was a combination of the master cylinder full of contaminates and the right front caliper. The new caliper didn't have a full stream of fluid when I cracked open the bleeder, but when I replaced it again, it would bleed good. I have good pedal now. Thanks for the input.