My one is green label 5HP18, parts number ZF 1056-000-104 , BMW 24002228631, serial number C538578 from ZF/Getrag, as far as I could see today from the pit, as I repaired the hydraulic hoses for power steering, was leaking, now I replaced the crimped return line with hydraulic hose and clamp, also the flow restrictor I found.
Apparently that is a bigger issue, BMWCCA even made an annoucement that they check the race cars for this self made mod
E36 power steering hose leak repair
E36 power steering hose failures

Over the past couple driving seasons we have seen a number of on-track failures of the power-steering-return hose on E36 '92-99 series, including M3. The failures we have seen were all the same; the return hose pulled off of the power steering cooler, right at the factory-crimped connection. This failure results in the fluid content of the power-steering system being disgorged in a few seconds, creating quite a hazard on the track surface for the afflicted car and following vehicles. Of course, power steering assist is also lost as well. Why these failures did not commence earlier in the E36 life cycle remains somewhat a mystery. Please note, that we have seen a new, OE hose assemblies fail on their first track session, so replacing the power-steering cooler/return hose assy with stock parts has been shown to be ineffective in addressing the problem.
Although there is not a complete consensus within the BMW repair community as to the cause of these failures, many feel that the primary problem is that the return hose should be longer, and that engine movement (probably more severe in the on-track environment) exaberates the problem. Deteriorated engine and / or transmission mounts can allow increased engine movement, and some feel that high temperatures may be an extenuating factor.
In preparing your E36 for a track event, it is imperative that you carefully check your engine and transmission mounts for deterioration, separation and for excessive motion of the engine and / or the transmission. This inspection is facilitated by the use of a long pry bar.

You should also seriously consider replacing the power steering return hose with a suitable piece of hose a few centimeters longer. BMW hose # 32411131524 (12 mm ID (inside diameter), cut to length) is known to work in this application. You will also need two hose clamps # 11151727509 (15-18mm). Some claim success with aftermarket high-temperature hose of 1/2 inch ID, but be advised that the BMW hose fits the nipple on the steering cooler more tightly than do some nominal 1/2 inch ID hoses. The ferrule is where the failure occurs.

Replacing the return hose is a straightforward operation. After the car has been secured on jack stands or a lift and allowed to cool, begin by cutting the return hose and allowing the contents of the system to drain into a pan.
Note that the return hose is the SMALLER of the 2 hoses attached to the power steering fluid reservoir. Then, CAREFULLY slit and remove the ferrule/hose from the power steering cooler outlet. An abrasive wheel can be used, but a cutting pliers will suffice. Ensure that the hose nipple under the ferrule is not damaged by slitting operation. If it is damaged, you will need to procure a new cooler return hose assy.
When the ferrule and hose have been removed from the cooler outlet, you should see the hose nipple.
Continue by removing the other end of the return hose from the power steering fluid reservoir, then cut the new hose to the appropriate length and install to the cooler and reservoir with two hose clamps. You may find that your removed hose contains a restriction orifice located about 10 cm from the reservoir. You can remove this orifice and push it into your new hose, securing the orifice with a third hose clamp. Refill the system with Dexron ATF or other suitable fluid and bleed the system. Check for leaks and you should be done. Copyright 2011-New Yersey Chapter, BMWCCA,Inc.
Power Steering Hose 12 X 18 mm (Per Meter) 32411131524 list price $36.87
hose clamp (actually for cooling system # 11151727509 (15-18mm) $1.30/piece