Great to hear that I have been able to finally give back something to this incredible community.
It has given me so much over the years and saved me countless bucks
However, again a question, haha

Does anyone know a part number for the Teflon seal within the detachable outer valve body?
Its ouside diameter is ~21mm / .83"
I have tried to search for these, but couldn't get a match:
90560-19001 to 90560-19009
90560-18001 to 90560-18009
90560-17001 to 90560-17009
Same for the 90562-XXXXX range.
(21mm outside diameter - 1.5mm thickness = 18mm inside diameter, so following other sizing schemes XXXXX-18XXXX might be correct.
This is how I found the other ones.)
Also no other part diagrams I have checked show this as serviceable on any other model.
As this seal is a relatively static one (only a slight amount of twist here) and because I have seen images of very similar worm gears / valve assemblies that do not have a seal ring here at all, I think I MIGHT be able to substitute a normal o-ring.
However, I have not yet removed the original Teflon ring to measure groove depth and calculate a fitting o-ring.
If no one comes up with a fitting part number, I will let you know what I eventually did here.
The only two questions are if an NBR o-ring will have a long lifetime here as firstly the groove isn't properly cut for an o-ring and secondly the pressure might extrude and destroy an NBR o-ring here.
There must be a reason they used Teflon here.
I'm guessing to limit friction when turning the stweeing wheel?
Not sure how much NBR would affect this.
Simply looking at pressure, the power steering pump itself utilizes NBR o-rings, so there shouldn't be any difference in pressure here.
Does anyone know the maximum pressure of the power steering system on an 80 series in general?
Cheers,
Mark