Its easy to change the O ring seal. The seal is inside, just in front of the nut on the housing. Just get a new O ring from a parts store. They will match it up. Bring the housing and gear in with you.

The new fuel filters have a trend of seperating from the top mount. See the next pic that shows the spring.

There is a spring under the fuel filter. I got the spring from my local hardware store.

The O ring between the water pump and manifold is a problem area for leaks.
I use 2 O rings and a washer I have modified.
Find a washer that fits inside the hole on the water pump.

See the next pics for further details.

File out the inside diameter so the washer fits over the nipple on the water manifold.

The washer fits over the nipple. Notice that is does not go all the way down to the bottom. Then the water manifold is installed, the washer will compress the 2 O rings, creating a better seal.