In Reply to: NAA piston pump O-rings choice posted by BlasterStumps on January 26, 2024 at 10:16:52:
The correct parts for the NAA HYD Piston, Wiper, and O-Ring are:
NAA-530-B HYDRAULIC PISTON
NAA-533-A O-RING
NAA-473-A LEATHER BACK-UP WIPER
ALL will also work on the 9N/2N & 8N Hydraulic Systems as well. The NAA piston was a better design than the original 3-Steel Ring Piston style. The Rubber O-RING is supposed to encroach a bit externally out of the piston groove to help form a seal. The leather back-up washer/wiper helps clean any debris when moving in and out. There is a neoprene wiper supplied by CNH, p/n 87051231 as shown, that some have used in place of the leather wiper. The jury is still out, (show me the data) if this was a better design or not. I've rebuilt several N's using the NAA parts with both the OEM
Leather Wiper and the CNH Neoprene Wiper with satisfactory results using both. I also recommend you spring for a new cylinder as well when rebuilding your system. An old worn out cylinder will only create headaches and you don't want to keep pulling the top cover and redoing it do you?
I can't verify if the CNH Wiper is still available or not, suggest you call your local CNG dealer first. You may have to special order it. Your call on what you want to use but these parts are right and all except the CNH wiper available at JUST8Ns.
CNH NEOPRENE WIPER, p/n 87051231:
Tim Daley (MI)