I just bought a 1984 245 DL as a beater car to get me around until I can finish fixing my Jeep. The only mechanical issue I've found with it is in the steering. When I go above 40 mph, the power steering seems to randomly give out. The steering will become tight and difficult to control, and it will usually want to go slightly left or right, but not forward. When this happens, in an effort to keep going straight, I end up weaving left and right within my lane, and I'm sure other motorists probably think I'm drunk. When the power steering kicks back in (which usually happens after hitting a pot hole or bump, or taking a sharp corner) the steering wheel could be facing any given direction when going straight. I think last time I drove it, the wheel was at 180º while going straight. Anyone want to help diagnose my problem? I can't afford anything too expensive. If it's going to cost more than the car's worth, I'll try and live with the steering issues for the next month or two until I can get back in my Jeep, but I'd really feel safer if it was working correctly.

One more note: I checked the power steering fluid, which was a tiny bit low. I added a little fluid, and checked the belt. The belt seemed okay, but yesterday I noticed an occasional screeching sound, which was obviously from a belt. The belt wouldn't screech at higher speeds though, which is where my problem is.