First, a little context; I have an M52B28 swapped E30 touring project car.
I originally had a regular E36 rack installed. It was hooked up to the P/S pump with a stock E36 high pressure line, which was [poorly] bent to fit (routed around the back of the subframe). The return line was stock E36. I had no issues with this setup at all.
A few months ago, I got my hands on an E46 Purple tag rack. With the install, I figured I would replace the bent high pressure line with a custom one made with AN fittings. The new line routes between the subframe and sump, next to the low pressure cooling loop. Everything seemed to go smoothly with the install.
I bled the system by going from lock to lock with the front wheels in the air, first a few turns without the engine running, then several more with. I dropped the car on the ground and did a few more turns. At that point in time, with the car not moving, I believe the P/S felt fine.
I took the car for a quick drive around the block, and that when I started noticing the issue. It felt like the power steering assist was "lagging behind" my steering wheel input. And it seemed to be getting worse as I drove, so I quickly went home and turned it off. I assumed it was just a leak at one of the banjo bolts, but they all looked fine. I noticed some fluid had managed to get out of the reservoir via the vent hole. The fluid looked cloudy with lots of tiny bubbles. Perhaps it's just air trapped in the system? I attempted to bleed the system again, but nothing changed. I left the car to sit so the air bubbles would clear out of the fluid.
After more testing, the steering is still very heavy when turned, but if turned and held at a position, the power assist seems to "catch up" and the steering wheel goes light again. Possibly the result of an "air spring" somewhere in the system? The power steering pump doesn't seem to make any noise, although it is hard to hear with only headers for an exhaust.
I ran out of time to work on the car, and left it for a few months.
Last weekend I started her up again, hoping the issue had magically resolved itself. It hadn't.
So I'm thinking the issue exists with the purple tag rack, or my custom AN line. I threw away the old high pressure line, I can't easily swap that out. I still have the old E36 rack though, so I could swap that back in. But before I go through all that effort, I wanted to ask the community for input. Has anyone seen P/S behaviour like this before?
Any help would be greatly appreciated.