Pump Losing Prime

My pump is often losing prime, so it isn't pumping water after it turns on unless I do one of the following:
1) open and close the filter basket
2) if 1 didn't work, I would add some water to the filter basket

Some observations I made:
- sometimes water comes out of the lid of the filter basket when I shut off the pump
- drips coming from the cartridge filter; seems to be from the gap of the metal casing clamp -- not sure how else to describe it -- see below for longer winded version
- a few drips from one of the pipe connections
- bubbles from the outlets

They didn't all come at once -- they came in the order I listed over a few seasons. I've checked that the o-rings for the filter basket and the cartridge filter don't have cracks.

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Suggestions from a thread I had hijacked :o
- lube o-ring and tighten the filter basket -- REALLY tighten it
- heat up pipe connection and tighten (?)
- check if o-ring has been "squared"

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The cartridge filter I use is a Quantum CM Cartridge Filter. It has a metal clamp that holds the cover and base together. The clamp itself has gaps (to allow flexibility?), and the leak comes from where the gaps don't cover. You see a diagram of the filter, but it's hard to see the gaps in the clamp: http://www.hydropool.com/cgi-bin/hyd...db/ml=100.html

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Tracking a thread I found that had a similar problem to mine:
http://www.poolforum.com/pf2/showthread.php?t=4131

Get a new o-ring, they're cheap. Then fix pipe leaks. The pump outlet side pipe leaks are easier to spot since you see water dripping. The inlet side leaks are harder to find but more important in solving your problem since the pump sucks in air through these. Try running a garden hose over the inlet side pipes to see if the bubbles in the filter basket window get smaller or go away.

I tightened the lid on the filter basket and the pump seems to be keeping its prime. Though the leak from the cartridge filter seems somewhat secondary, I'd still like to get it addressed at some point. What's a source of orings? I looked online and the one that fits the cartridge filter is about $20.