I have a very hard brake ped! I have a 12v and i think my vac pump is on the blitz? sometimes i have vac and sometimes i dont. Can anyone help?

 

It's very rare to have a fault with the vacuum pump itself, the most common problem is a vacuum leak somewhere in the system. The first thing to do is to tee a vacuum gauge into the system. At idle, you should have over 18 inches of vacuum. If not, you can isolate different branches of the circuit to see where the leak is. A common place is in the line that feeds the cruise control servo, located under the driver side battery. Battery acid can eat through the plastic vacuum line.

 

I isolated the problem, i took the mail line off the pump and sometimes it works and other times it doesn't?

 

The acid will also eat through the servo. That is what happened to mine.

I would check the brake booster as well. Had a blown diaphram on my Ford.