RE: $1,000.00 bounty offered to fix COMP ARF A4 steering
The twin cylinders on the servo are the main problem. Trying to match the two cylinders is a monkey humping a football operation. If there is ANY difference in the geometry you will have a differential between the fluid on each side of the steering cylinder. This will cause leaks, sucking air into the system, etc. Ditch the two cylinders on the servo and use one larger cylinder. This is the only way to make sure fluid in equals fluid out on both ends of the system. It's will solve most of your problems. Put a T with a valve on one lline to fill and bleed both sides of the system. Put them at the high point and the air will tend to migrate there. Also use a decent hydraulic fluid that is comparable with the plastics and orings in your system.