I've been trying the last several days to remove my accumulator but i can not get the spring lock joint at the firewall apart. Today the little autozone brand tool I was trying to use shattered.

 

It's a pain in the aurse. You will need to push the hose gently toward the firewall whole pulling the tool toward the front of the truck if that makes sense.

 

The lock spring could also be corroded and dirty, which is why it is being so difficult. Try getting a little bit of wd-40 in there to help loosen things up. Also when trying to insert the release tool, give it a little twist as you apply pressure. As jstockert said, push in on the hose while inserting the release tool. Pushing in will relieve some tension on the lock spring.