I just replaced my master cylinder, front calipers and pads. All went well in bleeding everything, but now my brake pedal just sinks to the floor. Where do I start looking? Thanks.

How did you bleed them? The 10 bleeders have a specific order and you need to normally do at least two rounds.

Also, if you used the pump, pump, hold method to bleed and you used more than the normal travel of the brake pedal (what you normally use on the street) you may have trashed the master cylinder as the seal contacted the "corrosion zone" in the MC bore.

"Also, if you used the pump, pump, hold method to bleed and you used more than the normal travel of the brake pedal (what you normally use on the street) you may have trashed the master cylinder as the seal contacted the "corrosion zone" in the MC bore. "

True, with an old master. With a new master, pump away, because there's no corrosion zone yet.

Could be the the new calipers. This is the same symptom one gets with the mismatched halves. Looks like it bleeds, but leaves air in. Check the dimples.
--
Art Benstein near Baltimore

http://cleanflametrap.com/calipers/

It's likely the Master Cylinder has air in it.

To bleed the MC on the car
- crack open the brakes lines at the MC
- depress brake pedal (thus expelling fluid and air)
- with pedal held down with a stick or whatever, tighten brake lines
- release pedal (thus bringing in fresh brake fluid from the reservoir
- test brakes
- if problem persists, repeat again.
The process is similar to bench bleeding except you are wasting a bit of brake fluid instead of returning it to the reservoir. And it's easier and can be done anywhere.

Have rags and water ready for clean up before the brake fluid eats your paint.

--
1980 245 Canadian B21A with SU carb, M46 trans, 3:31 dif, in Brampton, Ont.