Quantity needed for a refill
1.7 litres are required for a refill of the steering pump
Source: Owners Manual 1968 - 2nd ed - 1975 reprint

Check level
The steering pump oil level can be checked either hot or cold engine. Carefully read on the dipstick : two level marks (HOT / COLD engine) are displayed.
If an appreciable amount of fluid is necessary, a leak should be suspected.
Source: Diverse