I replaced front discs, calipers, and pads. Bled the brakes and pedal still went to floor. Replaced master cylinder. Pedal still went to floor. Hooked it up to scanner and cycled it 5 times. Pedal still went to floor. Hooked it up to a vacuum pump and sucked out more air. Pedal still goes to floor. Suggestions? I'm at my wits end!!

 

Help!

 

Ran into the same problem. Im at my wits end as well.

 

Did you bench bleed the replacement master cyl before installation?

 

Bench bleed and the master cylinder was purchased at a dealer. Pedal still goes to the floor. Also changed the abs pump.

 

Your reply is not clear.

Did you bench the replacement master cyl at the place of installation?
If not, a huge amount of air was injected into the hydraulic system and now has to be removed.

 

Did you ever find the problem? I’m in the same boat. Had a soft pedal so changed the master cylinder bench bled it and ever since the pedal goes to the floor changed the abs pump and hooked a scanner up to bleed and still no pedal even changed back to the old master but still no change, I can’t figure it out!

 

If the replacement master cyl was not bench bled, you can play all day hoping to get all that air out and waste a lot of good brake fluid.

Every time you get the air close to the exit point you stop and refill the master cyl. .
While doing that the air in the line is working it's way back to the highest point and the cycle repeats.
What you should do is use a pressure brake bleeder that keeps the master full and keeps the pressure constant so it all goes to the exit.. Most folks don't usually have this piece of equip and the job can become a real hassle.There are places in the newer brake systems that trap the air unless constant pressure and valves are kept open to allow the air to exit can be a real challenge.
Brake work today should be left to the places that have the necessary equip and knowledge of what is in the system..

 

the replacement master cylinder was bench bled multiple times but still no luck.

 

I wouldn't say at this time the master cyl is defective, but more than a few times I have had a few that were not good, .
And we get trapped into that feeling , it can't be the master because I just installed a new one, but it was JUNK.

All I can suggest is ,,,,,,,,,if you know how it is supposed to work and you did everything right and it still had a problem, Yes, it is a bad master cyl.

Something to keep in mind,
If the brake pedal on a present master cyl goes all the way to the floor, plan on replacing it.
Sediment settles in the bore after the normal place it used to stop. Once the rubber cups pass thru that grinding sediment it destroys the sealing capability of the cups and the master cyl is done. Hope this helps solve some of the problem(s).