07 Scag has no control resistance on the left side

I have a 2007 Freedom Z with the B&S motor. I replaced the hydraulic fluid later in the season last year and had no problems once the system was bled out. I recently fired it back up for the first time this year and found that the left side control has no resistance. Almost like it is not hooked to anything. It does drive the wheel, but it's a bit jerky and the power is definitely diminished. I tried to bleed it per the manual again, but that didn't help. It was parked on cement over the winter and there is no evidence of oil leakage on the ground, though the reservoir was slightly low.

Any thoughts? Please let me know if anything is unclear and I'll try to explain it better. Thanks!

07 Scag has no control resistance on the left side