Power Steering Failure

I was at a lapping day yesterday when after about 7 laps, I noticed the power steering reservoir starting to tear up. I could see drops of fluid dripping from the cap. After a little bit of cooldown, I put the car back on the track and after about 8 laps the car lost all power steering. Limped it into the pits and there was ps fluid sprayed over the driver's side of the bay. Let the car cool down, topped up the fluid, turned the car on and rotated the wheel side to side to bleed the system. No such luck. Was there trying to bleed/get it working for about 3 hours. Nothing helped. Even this morning I had to drive to work with no power steering at all, which is a BIG pita.

Question is, what could be the problem?

The wheel is actually easier to turn left and right when the car is off. When I turn it on and let it idle, it's much more difficult to turn the wheel.

Car has bpu mods including fmic. All fluids flushed and refilled before the track day, including the power steering with Dextron III synthetic ATF

I've also replaced the pump with 2 other used pumps and the car is still having the exact same problem. It's down for the winter now, but I drove the last 2 months without power steering at all because of the problem above. Could it be the rack? Any tests I can do to deny/confirm things?

There are a few things that are mentioned in the link below that may help?

http://www.mkivsupra.net/vbb/showthread.php?t=160908&highlight=reservoir+filter

For hard track uage, especially on tight circuits you NEED a decent power steering fluid cooler. The fluid was boiling! It WILL kill the rack seals! Most elegant way if you have a manual is to buy a water rad from an automatic and use the built in auto box cooler in the bottom rad tank as a PAS fluid cooler. Otherwise add a decent heat exchanger wherever there's space in a decent air flow, the LH aperture in a stock bumperis often a good option.

Sorry, I forgot to mention that I am already building a power steering cooler setup.

I bought this cooler: http://store.summitracing.com/partdetail.asp?autofilter=1&part=PRM-1001&N=700+0&autoview=sku

I'm planning to fit it where the stock-uk spec supra diff cooler sits, and run the lines along the frame somewhere protected (maybe near fuel lines, etc) to/from the rack and the reservoir.

What are your thoughts of running the ps cooler this distance away from the pump?

In any case, I still really need to fix the power steering issue, as I would need to know how to diagnose what the problem could be.

I guess it HAS killed the rack seals, unless a hose has collapsed internally (unlikely). I'd find a good used rack for it from somewhere. It seems ridiculous to run huge hose lengths to a rear mounted cooler, an the pump may well not like it at all. Stick it at the front of the car. You would have been better using a small engine oil cooler, IMO, that one may be marginal on track.

I guess it HAS killed the rack seals, unless a hose has collapsed internally (unlikely). I'd find a good used rack for it from somewhere. It seems ridiculous to run huge hose lengths to a rear mounted cooler, an the pump may well not like it at all. Stick it at the front of the car. You would have been better using a small engine oil cooler, IMO, that one may be marginal on track.

Isn't the pressure in the return line (coming up from the rack) pretty high anyway? I was planning to use that (right before it goes to the reservoir) and run that to the cooler in the back, and that back to the reservoir.

As for the PS problem, I also forgot to mention that when I take off the thick hose from the pump (the one that goes to the bottom of the reservoir), there is no pressure. I'm under the impression that it's supposed to be spewing out (it did when I bled it a few months ago when it was working), but now it's barely even dripping out.

Bump for above question

Just put a new or reconditioned pump and rack on it, and check the hoses for flow and degradation. Don't take chances with PAS on heavy cars

Update: Fixed the problem.

It turned out that it wasn't the rack or the steering assist unit on the rack.

There is a plastic anti-foaming device inside the reservoir, and when the fluid boiled over, it got so hot that it melted the plastic, clogging the feed tube.

Replaced it with a new reservoir and it's back to 100%.