I'm having issues I'm hoping someone can help with. I took my van in for inspection and both rear brakes measured at 250. The rear passenger parking brake measured 250, but the driver's side only 100. Needless to say I failed. Any idea why the parking brake on the passenger side works, not the driver's side?

I noticed that the automatic-adjuster screw on the driver's side was slightly stripped, but didn't notice anything else off. I'm guessing the rear left cable is stretched and needs to be replaced.

What's involved in changing it? Do I have to adjust the parking brake, or will it automatically tighten? Thanks in advance for your help.