Re-capping old car stereo - does this affect bias?
Capacitors in that application perform one of several general functions:

Power-supply smoothing or decoupling. If you're putting in the same values you'll be fine.
Audio decoupling capacitors to block DC going from one stage to the next. A wrong value here might affect the bass a little but, again, substituting the same values will be fine.
Tone control capacitors are unlikely to be electrolytic so you won't be replacing those.
Radio tuning capacitors are also too small to be electrolytic so you won't be touching those (and that's where you'd most likely cause problems).

The only way you'll affect bias is that if the old caps were leaking they may have pulled the bias one way or the other. By replacement you should be restoring everything to the original values.
Have fun!
You should be fine.