· All hail the mighty ZOM
The O ring seals aren't the bit that leaks. Well sometimes. The little O ring is just a dust seal. The big O ring is a static seal that seals the spindle nut. On the underside of the nut there is a seat that the smooth shoulder of hte spindle sits on. That's the thing that does the sealing. Check it's ok. Usually a bit of a clean and lube sorts it out. You shouldn't even have to replace the 2 O rings unless they are damaged.