Brake pedal goes to floor

[alfadave1]

Hi every one....
Hoping some one can help me, have an 02 v70xc.. Pedal slowly sinks to floor. Figured ok checked every were, no leaks found. Must be bad master cyl. Replaced with new OE ATE master cyl. Blended system, first with car not running then with car running . Car still has soft/goes to floor pedal. Any one have an idea if I am doing something wrong or might have missed something to check

Thank you
David

[ericjp]

Can you pump the brake pedal and it to firm up? If you can, you still have air in the brake lines.

[alfadave1]

No..... It doesent....wont pump up

[guymon]

Did you replace the pads and put the retaining spring on backwards?

[billr99]

I once had a front line blow out on an 850 and even with that the pedal didn't quite get to the floor despite having next to no brakes. Are you certain that the pedal goes to the floor and you have less than normal braking? I find Volvo brake pedals to be somewhat soft feeling anyway. Not to the extent of some American cars, but no where near the rock firm feel of, say, a Porsche or even a SAAB. Is there any evidence of a leak anywhere in the sense of a puddle on the floor or loosing fluid out of the tank? If you have no signs of a leak, especially by loosing fluid, then I'm thinking you don't have a good bleed. Did you bleed the MC by itself before you firmed up the line connections to it? Assuming all of this is good, then I would also suggest:

1) Not likely to be the cause but fairly common mistake...are the anti-rattle springs properly installed?

2) If you have no leaks at the callipers, any of the line junctions, or the master cylinder; then the only other hydraulic component in the system is the ABS pump.

3) The only other thing left after all of this is the vacuum unit and that doesn't cause you to lose pedal. Usually the opposite in that you get really good pedal but not much braking.

I'm betting you need to make sure the MC and the whole system is properly bled. Use a MightyVac or Motive Power Bleeder.

Good Luck,

Bill

[Astro14]

Did you bench bleed the master cylinder? If you don't purge the air from the master before connecting to the system, you may never get all the air out. Disconnect the lines at the master, purge it, reconnect, then bleed the system.

And post a picture of your caliper springs, though you don't say if you did pads, it's easy to install them wrong and the pedal will be very soft.