NAA Backup Washer / Buna-n installation ?

Ken(Ark) · Jul 7, 2016

I am ready to order orings and back up washers from McMaster-Carr . The expensive ones are split for easier installation and the cheap ones are not .

Question one , will the solid style back up washer stretch over the shoulder of an naa piston or are they only used on shafts with threaded collars or other ways of assembly ?

Question two , can I simply cut a solid backup washer or will that create a problem .

Thanks , I have only used the leather style and I remember it was a little sensitive and I have never worked on a hydraulic cylinder so I really don't know how most are constructed , Thanks - Ken .

Hobo,NC · Jul 7, 2016

I use the one piece backer from CNH no problem installing them. When I run out of those may give McMaster-Carr a go.

Ken(Ark) · Jul 7, 2016

(quoted from post at 11:22:30 07/07/16)
I use the one piece backer from CNH no problem installing them. When I run out of those may give McMaster-Carr a go.

I will order 50 baskup washers and 50 orings and post pic in a week or so .

souNdguy · Jul 7, 2016

I have used both the leather and the black cup shaped 'rubber' ones. both go on, both work.

Dean · Jul 7, 2016

Cannot comment regarding the units sold by McMC but the non "split" units sold by CNH assemble with no issues.

Dean

TheOldHokie · Jul 7, 2016

(quoted from post at 10:39:14 07/07/16) I am ready to order orings and back up washers from McMaster-Carr . The expensive ones are split for easier installation and the cheap ones are not .

Question one , will the solid style back up washer stretch over the shoulder of an naa piston or are they only used on shafts with threaded collars or other ways of assembly ?

Question two , can I simply cut a solid backup washer or will that create a problem .

Thanks , I have only used the leather style and I remember it was a little sensitive and I have never worked on a hydraulic cylinder so I really don't know how most are constructed , Thanks - Ken .

The ends of a "split" backup washer overlap. Sometimes called a spiral washer. Cutting a solid backup washer will no give you the same effect.

TOH

Ken(Ark) · Jul 7, 2016

Thank for all of the replies , I'll post pics when I get them in .

9452K49
Oil-Resistant Buna-N Multipurpose O-Ring, 3/16 Fractional Width, Dash Number 330, packs of 50 - $10.29

5288T359
Oil-Resistant Buna-N Backup Ring, 0.183" Wide, Dash Number 330, packs of 50 - $8.93

Merchandise $19.22

Hobo,NC · Jul 7, 2016

I know I have a bag of o-rings I picked up from mac-car I may have got the backers would have to look you will be OK with them.
I ordered them after TOH posted the numbers

O-rings are scary to deal with it has much to do with voodoo :lol:
I will admit I get lost once and awhile trying to figger out the dash number. I always figger it out once I pull my head out of my arse about all you need to know is the inside I.D. and the cross section.

http://www.marcorubber.com/sizingchart.htm

I got strummed a few weeks ago looking for metric o-ring specs in the link I posted there they were right in front of me :roll:

NAA Backup Washer / Buna-n installation ?

Ken(Ark)

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Hobo,NC

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Ken(Ark)

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souNdguy

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Dean

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TheOldHokie

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Ken(Ark)

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Hobo,NC

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