I installed new disc brakes sunday and now when I push on the brake pedal I hear a hissing sound and it is hard to press the pedal and stop. Any suggestions on what is wrong? I followed the Haynes manual to change my brakes. Please help

 

Were you ruff on them the first days they were on?

 

Not any more than I was the last time I change them about 1½ years ago.

 

Bleed the lines and check the fluid.

 

Do I need to bleed both front and back?

 

I would do both. Brakes are the most important system on your car.

 

Thanks. I will do that and let you know what happens.

 

The hissing points toward a vacuum or high-pressure-fluid leak, and the hard pedal could easily be caused by lack of vacuum to the brake booster. Check the vac line for the booster and also check to see if the booster itself will hold vacuum. The check valve may also be a culprit, but that generally doesn't cause a hard pedal.