front brake problems...not sure whats going on

my brakes were working fine until i changed the pads a few days ago.
i have done this a million times on other vehicles and dont know what happened this time on the volvo. removed the clip and the alignment bolts on the back of the caliper, pulled the caliper off, pulled the old pads off, opened the brake resevoir, pushed the piston back all the way, installed the new pads (with anti-squeal on the backing), reinstalled the calipers, tightened the alignment bolts, reinstalled the clip, and pumped the brake pedal a few times to get the piston where it needs to be. i felt both sides to verify my work. the passenger side was good, however the driver side rotor had play and was able to move around quite a bit. if i applied brake pressure the piston would grip, but it seems as soon as i let off it would recess a little bit allowing some play. now when i drive, it causes the car to shake at speeds above 30mph until i hit the brakes and it smoothes out.

why does that piston seem to recess itself a little bit if there is no brake pressure applied? is it something with the ABS?
also...the brake pedal travels further than it used to, and if i pump it a few times it builds up and doesnt travel too far, but if i stay on it hard, it falls the whole way down as if there was a leak (which there isnt).

what can i do?

thanks in advance!

matt

you may want to check that rubber pressure line to that side sometimes they collaps inside ad cause the piston to stay out aginst roter or cause slow release of piston

I found out what the problem was with my brakes. Make sure your caliper tension spring is on correctly. They can be put on 2 ways. One correct and the other is not. when they are put on incorrectly they will excessive travel on the brake peddle. The spring should go under the mount so it is pulling the caliper down onto the rotor. I hope this info helps you out.