Replace or reuse worn hydraulic lift cylinder?

kylemorley · Apr 7, 2014

Any good guidelines on when to condemn a lift cylinder? I pulled mine today, and found the bore in lovely shape - but for one lone scratch running the length of the bore, measuring about .008" across and maybe .005" deep after I cleaned up a bit with a cheap drill hone.

I hate to spend money on new parts when old will do but I am not experienced enough with these things to know how much leakage that will translate into.

Tom N MS · Apr 7, 2014

Are you going back with steel rings or are u going
to upgrade to a new piston with rubber O-ring? O-
ring is more forgiving..You will get many opinions
but as for what I'd do--- I'd probably hone some
more and do the upgrade..

Royse · Apr 7, 2014

If you can hone it smooth and put in the NAA style that seems to
be the recommended way to go.
My 8N had some pretty bad scratches, I honed it, but couldn't get
them all out and I was afraid they would cut the new o-ring, so I
put the original three ring style back in it. Worked fine.
I don't have an answer to what is acceptable in scratches.
I guess it would come down to how many times you want to do it.
I experimented with mine, knowing full well I may have to do it
over and replace it. It's been about two years I think, so not bad.

kylemorley · Apr 8, 2014

That's my next question. If I go with a new cylinder I will definitely go with the NAA piston, but I haven't decided what to do if I reuse the old cylinder. Reading the archives the standard recommendation seems to be to use the metal rings with old/scratched cylinders, on the grounds that the scratches will quickly chew up rubber seals, but I notice Zane, whose opinion I would not lightly ignore, says exactly the opposite:
"I would replace the ram cylinder with the piston made for the NAA series tractor. It has the Neoprene rubber ring with the leather backup washer. It is lots less likely to leak. Just hone the ram cylinder good to smooth up the scratches in the bore. It will not be possible to remove all the scoring in the bore of the ram cylinder but you don't need to for the NAA rings to seal off the oil".

mhb@ufe · Apr 8, 2014

I would also recommend the NAA piston as it is more likely to seal. Just make sure the honing took off the sharp edges so the oring doesn't get cut.

Mark

TheOldHokie · Apr 8, 2014

(quoted from post at 09:30:06 04/08/14) That's my next question. If I go with a new cylinder I will definitely go with the NAA piston, but I haven't decided what to do if I reuse the old cylinder. Reading the archives the standard recommendation seems to be to use the metal rings with old/scratched cylinders, on the grounds that the scratches will quickly chew up rubber seals, but I notice Zane, whose opinion I would not lightly ignore, says exactly the opposite:
"I would replace the ram cylinder with the piston made for the NAA series tractor. It has the Neoprene rubber ring with the leather backup washer. It is lots less likely to leak. Just hone the ram cylinder good to smooth up the scratches in the bore. It will not be possible to remove all the scoring in the bore of the ram cylinder but you don't need to for the NAA rings to seal off the oil".

It is not about sealing. Surface finish on hydraulic cylinders is critical to o-ring life. The rougher the finish the shorter the life and scratches are well beyond anything acceptable in the way of finish on an o-ring cylinder. Smooth edged or otherwise they will increase abrasion on the o-ring. A new cylinder costs $85 - how lucky are you feeling, how badly is your budget being pinched, and how excited are you about the prospect of possibly doing the job again in a few years?

TOH

R Geiger · Apr 8, 2014

What was the old one doing before you pulled it? Was it leaking to the point it would not hold anything up?

The last two that I have done were scored pretty bad. I honed them out somewhat. Did not remove all the scoring and went back in with steel rings and they both are still working just fine.
One 8 years ago and the other 3 years ago.
I would not put o rings in anything less than a polished bore. Honed is not a polished bore.

kylemorley · Apr 8, 2014

Your adviee, is, as usual, reasonable. But got to admit that I have
a perverse dislike of replacing parts unless absolutely necessary,
especially when replacing them means substuting 3rd world junk
for good honest American parts from the glory days of American
manufacturing. And, in this case, the job is pretty easy enough
to redo should it not work out.

That said, intuitively I shrink (as do you) from the notion of
fitting rubber dynamic seals to a less than almost-perfectly
smooth bore. Hence my interest when Zane suggests it. He
probably has more long term experience with such things than
anyone else here, so I figure if he says so, it's worth considering.

Oh, another thing I am toying with is cutting my old 3-ring to take the later setup in one of the grooves, ala John Smith.
I recall you offering to cut one for someone here a while back,
did you ever, and if you did, how did it work out?

Jason S. · Apr 8, 2014

I did the original piston on my Ferguson TO-20 like that. I had the third ring grove machined on a lathe and installed the oring and backup washer in it with the first and second grooves with steel rings. I did use a cylinder that had scratches left in it after honing. Almost two years later it is still working fine with that set up and I use this tractor a lot. It does all my plowing,discing,cultivating,raking hay,and I'm getting ready to pick 3 acres of corn with it and the hybrid set up has worked fine for me. I previously tried just the NAA piston and oring set up in that tractor and after 3 months I had a bad leak from the cylinder. I removed the piston and the oring was chewed up pretty bad. When I redid it this last time I made sure I got an oring and backup washer from CNH. There is a difference in them. When I compared them there was a difference between a CNH and Tisco oring and washer anyway...

R Geiger · Apr 8, 2014

(quoted from post at 00:34:11 04/09/14) I did the original piston on my Ferguson TO-20 like that. I had the third ring grove machined on a lathe and installed the oring and backup washer in it with the first and second grooves with steel rings. I did use a cylinder that had scratches left in it after honing. Almost two years later it is still working fine with that set up and I use this tractor a lot. It does all my plowing,discing,cultivating,raking hay,and I'm getting ready to pick 3 acres of corn with it and the hybrid set up has worked fine for me. I previously tried just the NAA piston and oring set up in that tractor and after 3 months I had a bad leak from the cylinder. I removed the piston and the oring was chewed up pretty bad. When I redid it this last time I made sure I got an oring and backup washer from CNH. There is a difference in them. When I compared them there was a difference between a CNH and Tisco oring and washer anyway...

It would be interesting to see what the o ring now looks like now!

TheOldHokie · Apr 8, 2014

(quoted from post at 11:34:11 04/08/14) . When I redid it this last time I made sure I got an oring and backup washer from CNH. There is a difference in them. When I compared them there was a difference between a CNH and Tisco oring and washer anyway...

I have no way of knowing what you were sold by either of those suppliers. But I do have the specifications for the NAA lift o-ring and backup ring as shown on the original Ford prints. They are standard AS568A rings that you can obtain from any good supply house. The AS568A dash size is AS-330, nominal cross section of 3/16", nominal ID of 2-1/8". The actual callout from the prints as shown below is identical to standard AS-330 dimensions and tolerances right down to the flash.

TOH

NAA-533A O-Ring

• Diameter: 2.090/2.110
• Cross section: .205/.215
• Max flash: .003 high, .005 wide

NAA-473A Backup Washer

• Outside diameter: 2.485/2.515
• Width: .183/.198
• Thickness: .084/.104

Jason S. · Apr 8, 2014

(quoted from post at 17:00:19 04/08/14)

(quoted from post at 11:34:11 04/08/14) . When I redid it this last time I made sure I got an oring and backup washer from CNH. There is a difference in them. When I compared them there was a difference between a CNH and Tisco oring and washer anyway...

Click to expand...

I have no way of knowing what you were sold by either of those suppliers. But I do have the specifications for the NAA lift o-ring and backup ring as shown on the original Ford prints. They are standard AS568A rings that you can obtain from any good supply house. The AS568A dash size is AS-330, nominal cross section of 3/16", nominal ID of 2-1/8". The actual callout from the prints as shown below is identical to standard AS-330 dimensions and tolerances right down to the flash.

TOH

NAA-533A O-Ring

• Diameter: 2.090/2.110
• Cross section: .205/.215
• Max flash: .003 high, .005 wide

NAA-473A Backup Washer

• Outside diameter: 2.485/2.515
• Width: .183/.198
• Thickness: .084/.104

I did have the measurements between the two written down but I do not remember where I have put the paper. I do still have a pic of the two side by side. The CNH is on the right in the pic

688888DE-AA5D-4224-A56A-9CC92C90C392-18802-000016919A304225_zps0d2a0218.jpg

mike-ga · Apr 8, 2014

I'm just glad you got answers to a question I asked a couple of days ago!! Couple nice guys tried to help me but you are getting more in depth info.

Hobo,NC · Apr 8, 2014

I would ask myself what caused those scratches... Then set out to find it and get rid of it...

I like new if I am spending your money...

The next question is how long do you expect the lift to hold up a implement...

I can tell ya with new parts the lift will stay put for days/weeks for what ever good that is but in time they all will leak down new old are abused.. I would like to see a lift stay up at least 5/10 min. loaded engine off... About the only time I would like to see it stay up longer is when I have a bush hog attached and have to make a long drive even then all I would have to do is disconnect the cutter drive shaft and leave the PTO engaged.... Its your money your time you can be the test dummy...

If the implement does not drop to the ground when I shut it off normally I can work around it..

Anonymous-0 · Apr 8, 2014

The Ford Orings that are/was used in most locations in lift covers were 90 durometer in stead of 70 that are in aftermarket kits.
They are made of a harder compound.

4play · Apr 9, 2014

My lift would hold about 30-45 minutes with nothing on it with cold fluid from max height to bottom , a heavy 5ft mower or box blade it would fall within 2-4 minutes with hot fluid. I had what appeared to be the original cylinder with a few scratches you could catch with a finger nail and a few rust pits. The piston and o-ring were not real worn and obviously not that used, in fact the leather washer was installed on the wrong side, it was split too not that it matters.

I already had a piston, o-ring and back up seal so I decided to replace the worn cylinder too. With an empty load the arms stayed up almost 2 weeks, I actually dropped them because I needed to use tractor. It held my box blade up overnight even after sitting with hot fluid.

TheOldHokie · Apr 9, 2014

(quoted from post at 23:02:44 04/08/14) The Ford Orings that are/was used in most locations in lift covers were 90 durometer in stead of 70 that are in aftermarket kits.
They are made of a harder compound.

NAA-533A was a 90 durometer Buna-N o-ring and a bag of fifty (p/n 5308T361) from McMaster will cost you $12. Just in case I haven't been clear. The only thing "special" about the lift cylinder o-rings you get from CNH is the price.

TOH

mbramble · Apr 9, 2014

And I have a bag each of the McMaster O rings and the backup rings

I used them when I rebuilt my top cover a couple years ago. They work great.

TheOldHokie · Apr 9, 2014

(quoted from post at 09:21:59 04/09/14) And I have a bag each of the McMaster O rings and the backup rings I used them when I rebuilt my top cover a couple years ago. They work great.

I see a (small) profit in your future ;-)

TOH - The Oracle of Hagerstown

Replace or reuse worn hydraulic lift cylinder?

kylemorley

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Tom N MS

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Royse

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kylemorley

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mhb@ufe

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TheOldHokie

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R Geiger

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