The React pump has one oil seal on the shaft that protrudes from pump body and 3 seals - one on each plunger. If you see an oil leak from any of these 4 seals at a service check (or you may notice that the oil level in pump body is falling), then these 4 seals will need to be replaced.
You can also buy the complete spare parts kit here.
Please read the user manual before servicing and watch our videos. If after watching you are not confident to perform this procedure we recommend finding a local engineering shop who can do it for you. If you are in New Zealand you can also send it back to us for servicing or join our service plan.