Argus c3 shutter speeds not accurate?

I bought a vintage Argus c3 recently. It looks like it was hardly used. The problem I have is with the rangefinder wheel and the shutter speed knob. Both of them are hard to turn. The shutter speed dial will not turn pass 25. Also, it seems that no matter what speed i put it on, the speed is still the same. Is there a way to fix the speed dial?