Farmall 450 hydraulic control valv

Revisiting my 450 hydraulics. (https://forums.yesterdaystractors.com/viewtopic.php?t=1392614). The fast hitch cylinder has been rebuilt. The tractor has two valves, Behlen power steering, and an M&W pump. I have had problems with foaming and decided to replace o-rings between valve bodies, column, covers, safety valve, and line connections. The column to reservoir gasket and column to steering gasket are not easily available so I made my own from a rubber fiber gasket sheet.

It has been an [u:8917c25a09][i:8917c25a09]unsuccessful[/i:8917c25a09][/u:8917c25a09] attempt.

To add to this, I made a big mistake - to keep dirt out, I had plugged openings with paper shop towels, then missed one while putting it back together. That piece has since gone through the system basically disintegrating. I ve replaced that oil, cleaned the filter in the reservoir, and cleaned the filter plug in the priority valve.

The pump is still loading unless I operate one of the valves. Power steering works well and does not appear to affect the loading.

The valve for the remote connection does not return to center when released. The valve is set for double acting. I removed it from the system temporarily and only had the fast hitch valve connected. The system still loaded.

While the remote valve was off, I opened each end of it but did not remove the valve from the valve body. I noted that the control valve guide appeared to be loose. It did rotate from the single to double position, but I wondered how loose this should really be?

My next steps are to open up the control valves and safety valve to check/clean them. Am I asking for more trouble? (as long as I don t leave another paper plug in it!)

Now what all is wrong here i am not sure as i am not the one that got into it in the first place . BUT here let me say this, When one is working on Fuel injection and hyd.'s , automatic transmission is that you NEVER have paper towels , rags layen around and or use them for whipping and cleaning . A tiny paper fibber can and will cause you a lot of grief a speck of lint off a rag will drive you bing bong . And you never work off a wooden work area . You want a steel surface that is washed down and blow dry . You have a way of washing off parts with CLEAN parts cleaning fluid next to your work area and a small container of hyd oil to dip the parts in as you reinstall . All parts are washed blow dried dipped and in stalled as you go No whipping with a rag or paper towel , your hands get to slimy then wash them off and Blow dry . making gskt. ya make gaskts out of the same thickness Metrial as Org. . Gskt making is becoming a lots art , but when i first started wrench twisting it was and every day deal . As a Kid working my first job i was doing a man's job working for a vary large construction company and was considered full time even though i was still in highschool , at the turn of my 16th birthday i was given a company truck and this was in the days before the fancy service truck that are out there today , But my boss along with the others at the main shop Built this new cab and chassis into what was like a service truck , we all worked on building the bed then came the 250 Amp PTo driven Hobart welder , then came the Garner Denver Air compressor that was run of the second PTO and it would pump the fuel , oil and grease , it would run the OTC porta powers , it would run two 90 pound jack hammers or rock drills , we could now split the tracks on the dozers and shovels as we not had a hdy track pin press that was on my truck . My self my boss and one shovel operator would also fill in as field mechanics when needed and we all had five different rolls of gskt paper and out in the field we would make the gskts we needed for most repairs other then engine . We had the tools to do this with as like any other job making gskt. does require some tools , yes as we called them ELF hammers were the first go to tool , then the hole punches , Circle cutters and Exacto knifes . The thin gskt metrial was the hardest to work with . Now it has been god only knows how long it has been since i was in a 400-450 hyd. valve set so i am a bit foggy on it but if i remember correctly the gskt used was thin and the use of the correct O/rings is a must .. Ya don't become and expert over night and unless ya haqve someone that has done this before standing there helping you your going to mess up , It's call tuission (SP) you pay to go to higher learning and so you shell pay to learn on something new , we all pay .

Do not remember the 400 valves as well but the 560 has a roll pin in a guide to hold the single/double position.You can check that. I believe the garter spring on the bottom end is broken on the ones that do
not center. Going on pressure can be the flow /pressure control. There is a small orifice and screen that can get plugged. My 400 I took it apart by taking two bolts out and putting longer ones in and then
taking the other two out slowly to relieve the spring pressure. The orifice comes out using a large screw driver. If there is a small ball in the end people discard that and I used a furnace drill kit to clean
the orifice out carefully. Gasket is cheap at CASE IH. Clean all the parts up and try it again.There is a pilot passageway in the control valves that turns the pressure on when moved. The flow control is what
monitors the pilot circuit. The valves may have a internal spring to center but am not sure.

In the regulator and safety block at the left end of the valve stack (part #5), there is a pilot valve that selects between demand and recirculate under low pressure. This is a spring loaded small diameter valve it has (sometimes) a steel ball that hammers the tiny hole small, and a screen that prevents the hole from plugging. The screen is pluggd, and the hole should be .038 to .040" (no bigger) that will fix it until plugged up again. Jim
diagram

Gentlemen, thank you for your responses.

Tractor Vet - thanks for the insight on the clean work area. I ll make adjustments as I go forward.

Roger/Jim - I have had the top cover off the regulator/safety valve. In the attached pic, I have removed and cleaned #10 (twice - nothing on it the second time) and removed and replaced the o-ring #20. I have gone no deeper than that. I put on a new top gasket #3.

I have the ends off one control valve, I did see the roll pin in the yoke. I ll get in to that valve when I finish with the regulator/safety.

Thanks again

Wonderful commentary Vet!

Dad had the same thing with our 450 after he had a shop that sand blasted and spray painted bridges and
Interstate over-passes in summer and blasted and painted farm tractors and other equipment in winter. I
won't comment about all the sand left under the fresh paint, but they blew the breather off the top of
the reservoir and got sand into the hyd system, not sure how or why the pump survived that but no amount
of adjusting the 2-way/1-way valves took the load off the pump. The pump itself would be too hot to touch
even with gloved hand in 5 minutes of idling. Think Dad had it hauled the 10 miles into town and 2 days
later it came back fixed. Wish I could tell you what they did.

I know I did this to myself. Yesterday I proved it by finding some of that paper towel I mentioned above in the safety valve.

I ve opened the control valves but cannot get them apart to check the orifice/screen.

Today I m putting things back together. I ll check back in when I have tested it.

Thanks for the replies.

Few more things on the hydraulic system. That orfice with screen, number 10 originally was .024.
When the 560 came out they increased the size to .031 and added a check ball above the orfice on
the screwdriver end. It was held in place with a roll pin.

First orfice with the ball had a soft seat and the ball peened it smaller. You could remove and
throw the ball away and easily drill the hole out . Later on they hardened the seat so ball would
not peen it shut. Those became much harder to drill out.

When I drilled them I usually went to about .040 but on some old beaters I had to go even farther
BUT, another thing here, the only way to clean that screen and orfice is to cut the end of the
screen off and after cleaning just roll it up a bit to close it off .

The operation of that assembly is that the flow through the orfice is directed to the top of the
regulator piston. This makes piston move and open the ball valve below piston and that provides a
direct route for the oil back to reservoir.

When you operate one of the aux valves, the first thing that happens is that you open a passage
that is hooked in parallel with the top of regulator valve. That passage way leads to reservoir.
When that path is opened, the oil going through that orfice now has a direct line to reservoir
so no pressure is applied to the top of the regulator piston. Thus, piston moves up from spring
pressure under the ball valve below piston and the oil is now directed through the aux valve to
load.

When aux valve is turned to single action, that passage never comes uncovered so system still
operates as if in neutral.

When lands on the aux valves wear, especially the land in a tele depth valve, more oil can escape
past the worn lands on valve than can pass through the orfice. That is why we drill orfice to over
come wear and provide enough oil to move that regulator piston down to unload system.

So, if orfice is too small or plugged, regulator piston just stays up and system stays on pressure
and gets real hot real quick.

There are no orfices in aux valve that will cause system to stay on pressure. There is a centering spring to return valve to neutral. There is a so called garter spring thats' purpose is to hold the valve in demand (pressure) position until unlatching piston kicks it back to neutral. That feature was never very good on those tractors.

Pete, thank you. I removed that screen twice and did not see a check ball. The screen appeared to be nearly new. Can t say about the orifice. I appreciate the detail you provided and intend to put a copy with my manuals.

I do have it back together. The system did not stay on pressure and the valves were working. There was a significant amount of foaming when I started it. I did let it run for 45 minutes or so and the foaming appeared to settle, so my guess is, I was seeing air that had been trapped in the system.

Thanks to everyone who provided assistance.