The parking brake is not working well, I adjusted it few times but is already adjusted to the max.
What it could be? I need to replace the cable?

 

How good are the Rear pads?

The E-brake setup is part of the caliper on the S40's.

If the E-brake isn't used for a while then used it might be seized in the caliper.
The only way to fix is replace the caliper.

 

The brake pads looks good but the dics not at all. By the way when I adjusted it I saw that the compensator (where the cable from the hand brake is connected withe the two cables that go to each wheel) wasn't straight.

 

Then you might have a bad cable if it is really off.