Replaced all hydraulic lines on my hoe (SN in sig), boom, dipper, etc Three of the lines are 5/8 ID hose and fittings come out standard fittings for 5/8 hose fittings I'm trying to find out what size O ring is used on the male side of the fittings. Looking at CAT I'm finding part number 6V-9746 but unsure that is the correct one. Picked up a couple from a local NAPA and they sold me #10 rings. Took them home and they are to big. I have some Nitrite rings and #9 is working but being Nitrite it won't last in Hydro oil. Can anyone convert it to a standard size ring?
If it an SAE size: AS568 Size Chart www.mroring.com
Aside from Cat part numbers, AS568 is the most common o-ring size standard for fittings used in the US, including SAE o-ring boss fittings. All AS568 size o-ring part numbers start with 568, then you have the series, 000 (ought) series, then 100 series, then 200 series, each series graduation is a thicker cross section. So a typical part number for a 568 o-ring would be like 568-014 ought series, or 568-114 100 series, etc. As for o-ring boss they specifically require 900 series o-rings, like 568-906, or 568-910. The 9 denotes 900 series, the numbers after denote the dash (-) size. If you have a 5/8 tube size SAE o-ring boss fitting, then that would be a -10, o-ring would be 568-910. If you use any o-ring on o-ring boss fittings other than 900 series it will fail.
ok, but unless the NAPA guy gave me something larger than a 10 , it was to big. I ordered new hoses and they all fit just by specifying hose ID and type of fitting Do agree the ring I have in there now will fail, and this is why I'm trying to find the correct ring Figure it has to be Buna-N or Vitron
Also when I search AS568-910 it comes up as Nitrel and Buna-N so could be my current O-ring box is ok. I thought it said nitrite but may have said Nitrel, will have to look
Measure the male thread OD of your o-ring boss adapter fitting, not the hose side of the fitting, the straight thread OD size where the o-ring goes. 5/8" tube size use 7/8-14 threads, and would be -10. If that's correct, the o-ring would be 568-910. No other o-ring other than that part number will work. Buna or Nitrile will work, Nitrile is just more abrasion resistant, which really isn't an issue with ORB fittings.
3/8" tube size, -6 ORB, 9/16-18 threads, 568-906 1/2" tube size, -8 ORB, 3/4-16 threads, 568-908 5/8" tube size, -10 ORB, 7/8-14 threads, 568-910 3/4" tube size, -12 ORB, 1 1/16-12 threads, 568-912
I am not 1oo% sure, but If I am understanding your problem, this is what you need. Has bailed me out on my old hoe! https://www.ebay.com/itm/173242899836?chn=ps&norover=1&mkevt=1&mkrid=711-166974-028196-7&mkcid=2&mkscid=101&itemid=173242899836&targetid=2274951440814&device=c&mktype=pla&googleloc=9007071&poi=&campaignid=22105563093&mkgroupid=172954124283&rlsatarget=pla-2274951440814&abcId=10164879&merchantid=101981954&geoid=9007071&gad_source=1&gad_campaignid=22105563093&gbraid=0AAAAAD_QDh_V-zD0Jz-8CX8GnAqTQzPP_&gclid=CjwKCAjwvNfSBhBiEiwAyaGMCb2_jBLFoHRSs6mluwxlasjUvHGnv4lSpIrGkrT5B7BS5BUZtf6s7hoCmxoQAvD_BwE
Didn't measure the male threads because I didn't want to mess with loosing oil again, measured the just behind the threads and it was 0.75 Wrench size is 7/8 on male and 15/16 on female fitting Looks like I had all the o-rings I needed to begin with, they are Nitrile / Buna-N
Oh, and note #9 is AS568 111
I think we need to back up and and clarify that we're all on the same page, because it's a distinction that's critical. Are you looking for the o-ring for SAE O-ring boss threads? Or are you looking for the o-ring for o-ring face seal (ORFS) fittings? The title of your thread clearly states ORB, which is industry abbreviation for O-ring Boss fittings.
Don't know how to answer that, I have hose fittings on my backhoe which have O rings and I asked and now we are here
It would help greatly if you could take a picture of the fitting you're working on that needs an o-ring and post it here. We really need to clear this up to properly help you out as ORFS and ORB are two totally different fitting connections.
Hopefully I didnt screw up this thread. What I posted is for ORFS fittings. That is what is on my NH backhoe.
It's a ORFS fitting, sorry for the mix up
So then, my post was the correct O-rings.
No worries, and easy enough. As other have suggested, you just need an ORFS o-ring kit. If you have a machine with ORFS fittings you're gonna need it.