Old D-5 Clutch Lever Adjustment

I have an old Cat D-5 about 1974 vintage. It is a powerdrive machine with hand clutches for the tracks - levers you pull back to release clutch.
The levers have a spring return that puts them back in the drive position after you release the lever. Recently the left clutch lever suddenly stopped returning as it should. I traced the mechanism and found under the seat where the return springs are located. The left spring is completely retracted when the clutch lever is in the engaged...

Old D-5 Clutch Lever Adjustment

Old D-5 Clutch Lever Adjustment