Brake issues

[Barrett Palumbo]

2500 2014. So I had a soft to the floor break pedal, so I replaced the master cylinder today. Same issue. NOW WHAT..thanks I do have power steering..

 

[jws123]

2500 2014. So I had a soft to the floor break pedal, so I replaced the master cylinder today. Same issue. NOW WHAT..thanks I do have power steering..

Did you bleed the system after you changed the master cylinder? Also did you check for blown/rusted brake lines.

 

[1999 White C5 Coupe]

2500 2014. So I had a soft to the floor break pedal, so I replaced the master cylinder today. Same issue. NOW WHAT..thanks I do have power steering..

The shutter valves in the ABS controller must be bled via a computer, in addition to bleeding the rest of the system.

 

[Barrett Palumbo]

so I had the same issue, prior to replacing the master. I do have a little brake at the end of the pedal. Could I have a ABS issue and there was nothing wrong with the master cylinder. No leaks or loss of fluid…
update I have no codes for ABS or brake system.
my ABS module is up by the firewall not down by the shock…

 

[Jeepwalker]

Hard to say what caused the initial soft pedal. That's a valid question. Master cylinders can leak internally between the internal seals. In fact, it's real common: corrosion build up inside the m/c bore (from moisture in the brake system), OR ..a seal on the piston breaks down or wears/tears, etc ..and then it can allow a small amount of fluid to leak by.

This is just a thought ....it's possible (and probable) you may have solved the main problem by replacing the m/c, but created another condition with air in the ABS. That's normal. It's almost impossible to replace a m/c *without* getting air in the ABS. So you just need to bleed the ABS. Then once the air is out of the ABS, re-bleed out the rest of the system. It's also possible there could be an ABS issue. IDK. I probably would have done what you did and replaced the m/c. That sounds more like a m/c issue to me. But I'm not there either.

There's videos on Y/T how a tech can do a real-world bleed by going on an abandoned country road or a long, abandoned parking lot where the vehicle can get up to speed, put two wheels on the gravel and slamming on, and riding the brakes hard (engaging the ABS on that side). Repeat for the other side. In lieu of a scan tool. Then bleed the air downstream from the rest of the system afterwards. Making sure the reservoir never runs out of fluid.

 

[Burla]

The shutter valves in the ABS controller must be bled via a computer, in addition to bleeding the rest of the system.

x2 gotta clear it, somehow air got in system. Very common to stay soft til it's cleared.