Ford NAA Unloader Valve O Ring Question

RAYWILSON · Aug 6, 2015

Folks,

Working to get my Jubilee hydraulics up and running. I have multiple problems I'm working through. One of the problems caused me to buy a new lift cylinder from an eBay seller. Neither the 'new' lift cylinder or my original lift cylinder had a unloader valve with the O-Ring present. Nothing there. Not even debris, residue, nothing.

Q1; What the heck happens to the O-Rings?! Hydraulic pressure chew them up and spit them out?

Q2; Are the Unloader Valve O-Rings necessary? Some say to make sure you get the New Holland O-Ring or you'll be sorry. Were/Are the missing O-Rings non-New Holland?

Q3; Where does the O-Ring go? The parts breakdown implies the O-Ring goes over the shortest stub at the end of the Unloader Valve. I would appreciate confirmation that indeed it goes as shown below.

Verus this:

Q4; I have no desire to redesign the Jubilee hydraulics, but it's real hard to see what the O-Ring does! <rhetorical question>

Appreciate the help!

Best regards,

Ray

Dean · Aug 6, 2015

Most O-rings are synthetic materials. Such materials deteriorate with time even if not a wearing item. Design engineers rarely specify unneeded parts.

Do yourself a very big favor and buy the proper O-ring from CNH.

If you do the job properly, it is likely that your grandkids will not need to do it again.

If not, you will likely be pulling the lift cover within a few months.

Dean

JMOR · Aug 6, 2015

I do not have a clue what you have there! All I know of used rubber/synthetic O-ring, except some early hundred series & they used a steel ring like the one pictured. The NAA would look just about like that but have the O-ring in the same place that the steel one is here.

Bern · Aug 7, 2015

I don't know what valve you have there, but it's not the unload valve. Might explain why you didn't find an o-ring on it.

WayneIA · Aug 7, 2015

It sticks in my mine that the first NAA's had an unloading that was metal to metal with no o ring. That pictured could be the valve .The pictured o rings are somebody's nonfunctioning afterthought. I believe this system was replaced with a valve, with a o ring in a groove fitting into the original bushing in the cylinder housing

RAYWILSON · Aug 7, 2015

Folks,

Appreciate the input - although I've gone backwards with respect to unloader valve clarity! We'll get there.

In almost all discussions with regard to non-functioning NAA hydraulics, somebody will recommend ensuring the unloader valve is cleaned up and does not stick. And wears the OEM O-Ring. Does anybody have a picture? Seems everyone overhauls this part - perhaps a picture of this beastie exists.

Meanwhile, I've found a Ford promotional video that shows hydraulic fluid flow through the system. The valve I picture above most resembles the valve Ford calls a By Pass valve in the video. The video has no such valve labeled "Unloader Valve".

All I want to do is to get this critter back together and workin'!

Here's the hydraulic faults I've found so far on this Jubilee:

1) The Safety and Check valve had a broken spring. This is the critter that has the ball that can be either glass or metal.

2) The Control Valve spring was in pieces.

3) The lift cylinder mount threads were stripped/rethreaded to a coarse thread that prevented the lift cylinder from being tightened adequately against the lift cover.

4) And because of Number 3 above, the gasket between the lift cylinder and top cover was blown out.

5) The lift cylinder itself was gouged and scored rather badly.

6) The rear section casting has needed 4 Heli-Coils to repair stripped or soft threads for the top cover bolts.

7) Specifically, the two threaded holes on either side of the pressure tube (the most critical!) were not capable of holding torque. Worse yet, one of the two had a broken out piece of the casting leaving only a couple three threads for the bolt closest to the pressure tube. I've made up a screw stud for that particular hole, JB Welded in, with a nut down below. It should be man enough to hold against the pressure.

Appreciate all your help!

Ray

JMOR · Aug 7, 2015

(quoted from post at 06:32:51 08/07/15) Folks,

Appreciate the input - although I've gone backwards with respect to unloader valve clarity! We'll get there.

In almost all discussions with regard to non-functioning NAA hydraulics, somebody will recommend ensuring the unloader valve is cleaned up and does not stick. And wears the OEM O-Ring. Does anybody have a picture? Seems everyone overhauls this part - perhaps a picture of this beastie exists.

Meanwhile, I've found a Ford promotional video that shows hydraulic fluid flow through the system. The valve I picture above most resembles the valve Ford calls a By Pass valve in the video. The video has no such valve labeled "Unloader Valve".

All I want to do is to get this critter back together and workin'!

Here's the hydraulic faults I've found so far on this Jubilee:

1) The Safety and Check valve had a broken spring. This is the critter that has the ball that can be either glass or metal.

2) The Control Valve spring was in pieces.

3) The lift cylinder mount threads were stripped/rethreaded to a coarse thread that prevented the lift cylinder from being tightened adequately against the lift cover.

4) And because of Number 3 above, the gasket between the lift cylinder and top cover was blown out.

5) The lift cylinder itself was gouged and scored rather badly.

6) The rear section casting has needed 4 Heli-Coils to repair stripped or soft threads for the top cover bolts.

7) Specifically, the two threaded holes on either side of the pressure tube (the most critical!) were not capable of holding torque. Worse yet, one of the two had a broken out piece of the casting leaving only a couple three threads for the bolt closest to the pressure tube. I've made up a screw stud for that particular hole, JB Welded in, with a nut down below. It should be man enough to hold against the pressure.

Appreciate all your help!

Ray

Bern · Aug 7, 2015

The NH parts book does not support your theory. Having said that, Ford parts books have never been the last word on much of anything.

Bern · Aug 7, 2015

Follow the dashed line of #6 into the cylinder. Is that where yours came from?

RAYWILSON · Aug 7, 2015

(quoted from post at 07:38:34 08/07/15) Follow the dashed line of #6 into the cylinder. Is that where yours came from?

AHA! Yes - same bore, just different part... WayneIA mentioned there was a 'old style', and I am jumping to the conclusion I have the old style - my actual Unloader Valve is pictured at the beginning of the thread. So my original Unloader Valve was the old style, as is the replacement that came off eBay pictured. Thank you JMOR for posting pictures.

In my travels I came across an old FORD parts manual that clearly shows the old style such as mine. I'll scan the page in post to the thread for completeness.

By the way, I need to add Item 7 to the list of things found wrong on this Jubilee hydraulics. The Hydraulic Pump Relief Valve failed a test with 110PSI compressed air. This is the valve down in the casting right above where the two hydraulic lines bolt up from the bottom. For post mortem, we took the valve apart and the little steel ball in there was crudded up with some sort of grunge that wouldn't polish off, and the inner spring was broken into three pieces.

Now, I'm don't begrudge replacing something that has been in there since 1953 - but what I am not particularly philosophical about is paying $96 to replace it! The similar valve on 100 series is less than $30.

Best regards, and thank you for all the help.

Ray

RAYWILSON · Aug 7, 2015

As promised, here is the apparently early Parts Book page that shows the original Unloader Valve. Same as in this thread's first post.

A couple of take-away points:

1) New Holland's online parts book may not show you the 'early' versions of some parts.

2) There was no O-Ring on the early style of Unloader Valve - so no mystery as to where they went. They weren't there in the first place!

3) Early styles were/are rarely the 'more reliable' versions. Gotta wonder how this will play.

It is what it is.

Much appreciate the help.

Best regards,

Ray

Bern · Aug 7, 2015

Looks like you solved the mystery. Another thing I noticed between your old diagram and the current online version is the lift piston seals. The original version used cast iron rings, much like engine piston rings. The current picture shows the more modern o-ring and backup washer, with no mention of the old style, most likely because the vast majority of the lift cylinders have already been converted over to the new style seals. I suspect the rational was the same with the unload valve.

Makes me wonder if there's a really old service bulletin out there somewhere about upgraded unload valves for the NAA/hundred series tractors.

NoNewParts · Aug 7, 2015

good info in this thread.
got me curious, so I looked in my various NAA books.
My parts manual, and the later IT manuals show the newer version and o-ring.
but the old IT shop service manual I have, copyright 1954, price printed on the cover of $2.00 shows the early version and metal rings.

again, good thread, thanks for the info

WayneIA · Aug 7, 2015

I'll bet you are right on a old service bulletin as I seam to remember replacing the valve to the o ring style if you were there for other reasons. But, I do not remember the steel piston rings

Doug (OH) · Aug 9, 2015

Looks like you have your work cut out for you, Ray. Good thread! Please let us know how everything turns out. Thank you!
Doug

Ford NAA Unloader Valve O Ring Question

RAYWILSON

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Dean

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JMOR

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Bern

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WayneIA

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RAYWILSON

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JMOR

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Bern

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Bern

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RAYWILSON

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RAYWILSON

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Bern

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NoNewParts

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WayneIA

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Doug (OH)

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