Rebuilding the Case 580D Backhoe Control Valves – External Wiper, source/part number?

I have a Case 580D with very leaky backhoe control valves. As the complete rebuild kit is no longer available I have been attempting to put together an order for the replacement parts (o-rings etc.) for the different valves of the unit. I think I have found all of the parts with the exception of the "external wiper" located on the top of each valve. It, for some reason is not listed in the parts manual but is necessary to keep dust and dirt out of the valve. Any information would be greatly appreciated. If anyone is interested I will be glad to share the replacement part numbers from Hercules Seal Products that I have found thus far.