Resolving Farmall 60 Series Hydraulic Problems.

(or How to Succeed by Really Trying)

Background

Ever since Dad bought the 460 in 1975, it was continually plagued with hydraulic system problems.  My recollection of Dad's first complaints about it was the Fast-Hitch seemed to have a mind of its own.  The hitch height wanted to hunt up and down resulting in very uneven plow depth. Add to that the fact that the only hitch point for other implements is on the Fast-Hitch drawbar, and you find yourself with a rotary mower scalping the sod after a while or cutting too darned high. Another complaint was water finding its way into the sump sludging and freezing up everything. Over time the system degraded to the point where it would not develop enough pressure to lift the drawbar if the mere weight of a person were standing on it.  I noticed its poor performance when I re-acquainted myself with the 460 three years ago while disking.  The system would barely lift the disk and this only if the throttle was pegged.  Two years ago I had to cut short my first-ever Plow Days because the 460 would not lift the 3-bottom plows out of the ground.  I had to let the system cool, start the tractor and rev it like crazy for just enough plow clearance to embarrassingly limp home. Fortunately home port was only 3/4 mile away. Additionally the power steering performance wasn't the greatest either but worked OK. We consider the 460 as our ‘lead’ tractor, but in its condition it seemed a poor relic of itself. This is hypocritical on our part if we want to call ourselves IH experts.

I set two 460 upgrade goals for this year (2004): getting the TA and the hydraulic system fixed. Since the TA worked fine on the high side, but the hydraulics were non-existent, the hydraulics would come first.  There are a good number of questions posed on the Antique Tractors web site (YT) regularly about problems with 60 series hydraulics.  Seems like this is a weak point of these tractors.  This write-up is meant to be a guide in fixing these problems.  Hope it helps.  -- Joe

Here We Go (April 2004)

It was quite obvious to any idiot that the pump simply wasn't doing its job, but was the pump OK? Just because there was no pressure doesn't mean that the pump was shot. There was the possibility that the pump wasn't picking up any oil, or the control/relief system was letting the pump's output just dump back into the sump. Since the hydraulic system was nearly non-existent, but the power steering still worked adequately, I suspected that the two systems were served by individual pumps. The I&T manual confirmed that.

For starters, when troubleshooting and servicing a Farmall hydraulic system, a manual is a must-have item. The I&T manual for this series tractor does an outstanding job in stepping you through the particulars, but it comes up a bit short in some other areas which I will cover here. 

The hydraulic pump and the power steering pump (if so equipped) are located behind a roughly 8" x 10" mounting flange on the low left side of the TA housing.  A rather large (3/4) hydraulic hose connecting to the rear side of the mounting flange quickly identifies where the pumps live.

The I&T manual instructs you on how to check the output pressure of the pump, but this involves inserting a valve between the pump's 3/4" output hose and the port entering the left dash support bracket (this also serves as an oil passageway to the hydraulic system). Getting the valve connected in line requires a hydraulic fitting adapter.  The test pressure gauge (should be of adequate range-3000 PSI) for the pump test screws into a very handy port threaded into the pump mounting flange oil passage.  However, this test port is a machine thread so another adapter is required if the test gauge has a pipe thread stem which mine does. The idea behind all this is to isolate the pump from the rest of the system.  Start the tractor, give it a little throttle and watch the test gauge as the test valve is slowly closed.  If the pump is OK, pressure will quickly climb on the gauge as the pump is beginning to work against a valve that is closing down.  Pressures should register in the neighborhood of 1900 PSI. WARNING! Do not completely close the valve! If your pump is good, it will soon not be by deadheading oil into a closed valve. That oil must go somewhere--if not through the valve, then through a now broken hose or  worse yet, a grenaded pump casting! I've seen this happen. If the pump pressure registers OK, then the hydraulic system's problem(s) lie elsewhere.

Another way to check the tractor's hydraulic system was suggested by Mike and it makes sense: rig a test assembly using hydraulic hose, a tee, pressure gauge and shut-off valve.  One end of the hydraulic hose needs to be equipped with the appropriate quick-disconnect so that it will plug into one of the remote hydraulic outlets.  The tee provides the port for the test gauge, and the shut-off valve provides the resistance.  Plug the assembly into a remote port and let the other end dump pumped oil back into the sump by way of the system's fill hole (near the shift lever).  Following the instructions in the above paragraph, this will let you see if the tractor's hydraulic system will produce pressure.  Testing this way does not isolate the pump from the hydraulic system's regulator control, but it is a quicker hook-up and will eliminate questions as to whether an attached implement's cylinders are bad leakers and not allowing things to work properly.

Well...I didn't do any of the above. I didn't want to mess with buying hydraulic adapters. Besides...that test was going to tell me what I already knew: the pump was gonzo.

Got to hand it to IHC--removing the pumps by way of unbolting the mounting flange from the TA casting is a piece of cake. Simply begin by removing the 3/4" output hose by unscrewing the (3) cap screws from the special hose connection flange and remove the hose entirely from the dash support casting by unscrewing the swivel O-ring seat fitting. There is an O-ring in the hose connection flange. Don't drop it in the crud as I did. Inspect the O-ring on the swivel fitting. This can get out of "O" shape after time allowing for mucho oil weepage here.  Remove the two cap screws from the steel power steering line's adapter flange--there's an O-ring in there, too.  Don't drop it in the crud as I did.  There is nothing else you need to do with the power steering lines as they flex enough to allow removal of the hydraulic pump mounting flange.

1. Pump mounting flange.  2. Power steering outlet. 3. Power steering pressure test port. 4. Hydraulic system pressure test port.  5. Hydraulic outlet flange adapter.  6. System hydraulic level test plug.

The hydraulic pump and power steering pump are bolted to the mounting flange with the (4) large cap screws surrounding the pressure test ports.  The mounting plate flange with the pumps will pull out similar to a file drawer. 

Remove all of the 3/8" cap screws from the pump mounting flange. Pay attention to one of these. It's longer than the others and is located toward the middle-rear of the flange. This one is sneaky--it looks likes a test port plug.

After all the mounting flange bolts are out, whack the pump mounting flange to loosen it.  Pry bars will probably be necessary to break the gasket's death grip. Our 460 likely has never been apart here since it was built 45 year ago.  Old farts do not like change!  Don't even try to save the gasket--it'll only cost you about $4.00 and, yes, they are still available.  The mounting flange and the pumps will pull out of the TA casting similar to a file drawer. This is a nice design.

Before going any further, special note should be made of the pump mounting flange gasket. The I&T manual says that the thickness of the gasket should allow for 0.002" to 0.022" of backlash between the PTO drive gear and pump driven gear. Combinations of different gasket thicknesses should be installed to meet this requirement. Well...how in the hell do you measure this backlash once the pump flange is bolted up!! Don't sweat this. Measure the thickness of the old gasket. The factory set this up correctly during assembly, so just buy a gasket or combination thereof that matches what you micrometered. In my case, the old gasket miked 0.025". I got one gasket ($4.00) that was 0.023" thick. Close by-gum enough!

I got the pumps with their mounting flange in Mike's shop, and we both had a look and made comments about that stuff not seeing the light of day since sister Peggy was born--1959. The power steering pump is piggy-backed onto the hydraulic pump via (4) bolts and is a tidy arrangement. Rotating the pumps' drive gears by hand was very easy, but Mike noticed a considerable amount of side-to-side movement of the drive gear end of the hydraulic pump's shaft.  Knowing that hydraulic pump clearances are typically in the range of 0.00", we felt we had found the problem. Unbolting all this stuff from the mounting flange and disassembling the pump is as easy as pie, and we quickly had it apart. While the gear rotors looked great, Mike's index finger revealed very deep gouges in the housing bore probably in the neighborhood of 1/32". As far as hydraulic pumps are concerned, 1/32 of an inch may as well be the Grand Canyon. Well...this pump simply could move no oil if any resistance were applied. The power steering pump felt fine. We didn't disassemble it but set it aside.

Bill was in Mike’s shop getting his 400 back together trying to wrap up the major rebuild.  While Mike and I were musing over the pump’s condition, Bill shed some light on the situation; "You know the 460 always got water in it, and I remember Dad coming home one time to plow snow out of the driveway.  The hydraulics were frozen up again.  He got mad and jerked the filter out of it, drained the oil and dumped 10 gallons of diesel fuel in the sump and ran it.  I figure he ran it that way for 10 years." Jumpin’ Jehosephat!

We blew Taps over the shot pump and within four days had a rebuilt pump in the shop courtesy of Steel Wheel Ranch. It should be noted here that the 460 was equipped with either a 12 or 17 GPM pump-- the latter usually is installed in the 460 Utility to facilitate loader work. Check the S/N of your tractor for the correct pump sizing. Ours was the 12 GPM unit. Also, these tractors were equipped with Thompson or Cessna pumps and both are used interchangeably. Ours was a Thompson: may it rest in pieces. We received a rebuilt Cessna.

Installing the new pump and the old power steering pump onto their common mounting flange was as easy as the removal. One very important piece of the hydraulic system pie is the suction pipe. This simply plugs into an O-ringed port in the hydraulic pump and provides a common source of oil for both pumps. Renew the O-ring in the pipe port located in the hydraulic pump—might as well while you’re there. Inspect the pipe for gouges or dings. The longer end of the pipe is what goes into the hydraulic pump. The other end has a small flange backed by a rubber sealing ring. Inspect this also. The sealing ring provides an air tight connection inside the TA housing’s pump feed port. By the way, a new pump comes without the drive gear so you have to use the old one. This swapped easily—no pullers or pressing was needed here.

Got to hand it to IHC again. Re-installing the pumps onto the tractor was very straight forward. Be sure the new mounting flange gasket is oriented properly and not covering some bolt holes. The gasket can easily be flipped the wrong way 180 degrees—yes I did this! The whole assembly just plugs into place. Recognize that there are two index pins on the pump mounting flange and just don’t force anything. All should plug into place very easily. Forcing things will likely result in a dinged-up suction pipe allowing the pumps to suck air instead of oil.

This is a good place to talk about the hydraulic suction side of things.  A pump that is cavitating (sucking air) will sound very whiny, there will be little to no pump output and the oil will look milky.  This is from air bubbles mixing with oil. Cavitation will damage a pump over time. The I&T manual is clear about careful re-installation of the assembly.  Dinged suction pipes are usually the result from horsing the assembly into place.  If you suspect cavitation, first check the oil level.  A plugged filter will not allow oil to flow to the sump, so check this, too.  To be safe just replace it. If this is OK, then look for a bad suction pipe and suction pipe sealing ring. This is easy to do as the assembly slips out pretty easily.  If all this is

These pics show where the filter is located and where you fill the system (left).  The fill port is in an unhandy place but is paradise compared to where the W-9 has its tranny fill hole!  Sorry for not cleaning up the operator's deck for this pic, but this just shows you the Old Gal still can do some work wacking corn stalks.

fine, and you still suspect cavitation, then you’re in deep poop! The only other thing it could be is an O-ring that seals an oil passageway between the TA housing and the transmission. It’s tractor splits-ville to fix this bugger.  By the way, milky looking oil is not solely caused by air entrainment.  If water is getting into the system, quality universal hydraulic fluid will trap and isolate moisture causing a milky-colored look.  However, this color is accompanied by a gooey, monkey snot feel to it--you know...slimy.  IH tractor operator platforms are notoriously bad leakers.  Best to keep them under shelter when it's wet.  The 460 suffered dearly from being out in the elements too much.  Snotty oil will plug the filter, too.

I got the hose and power steering lines on and topped off the oil.  Now the moment of truth: will decades of diseased hydraulics be behind us?

I had a difficult time getting the 460 to fire. The battery was low, but I had a start booster clamped on.  Despite this, it just didn’t want to crank easily.  It DID finally start and immediately a terrible chattering, screeching sound was heard.  I killed the tractor instantly, and my first thoughts were that I had wiped out the pump drive gear. I looked down at the fast hitch and noted that it had raised up a bit. That indicated the pump had picked up prime and was moving oil. Good. That proved all was OK on the suction side.

I started the 460 again and the terrible noise returned. I didn’t panic this time, and the noise registered to me as the relief valve blowing off. The noise would cease when I was moving the hitch up and down. The instant hitch movement stopped—oil flow to the lift cylinder stopped—the noise would return and the tractor would nearly stall out. Apparently the control system somewhere kept the system in a high-pressure condition all the time except when oil was flowing to a cylinder. This explained why the 460 cranked over so damned hard. I didn’t feel any closer to resolving these hydraulic problems at all.

I threw some questions out to the wonks on the YT website, got some ‘things to look for", and studied the manual. The following weekend Mike towed us up to his shop with the 504 where we could do some serious trouble shooting.

This first thing to check when experiencing a continual high-pressure state is the position of the remote cylinder spool valves. Our 460 has two, and in IH parlance these are called the Hydra-Touch valves. The spool valve control bank is located beneath the dash and behind the sheet metal cover that the brake set pull rod attaches to. There are two holes (if you have two Hydra-Touch valves) in this cover, and exposed ends of the valve spools stick through these holes. The spools have flats on them enabling the spools to be turned for selecting operation of two-way or one-way remote cylinders. Remove the sheet metal cover. You will see (or should see) roll pins through the spools and small keeper spring clips that index the roll pins. Sometimes the roll pins get bent, are gone, or the indexing clips are broken. This condition quite likely will allow the spool selection position to be incorrect and be "between" settings. This will confound the hydraulic system and cause a continual high-pressure, engine-bogging condition.

Well…our Hydra-Touch spools, roll pins and clips looked factory fresh, so we looked elsewhere for solutions. The system relief valve/pressure regulator control block looked like the next forensic adventure. The control block is bolted to the left dash support casting bracket mounted low and close to the tranny. There is a cover cap that faces rearward held in place by (4) 5/16" cap screws.

We pulled the gear shift for a less cluttered work area and began loosening the cap screws. This cap compresses the system pressure relief spring so we didn’t remove the screws-just loosened them. I popped the cap a couple of times with a hammer to break the 44 year old gasket grip. Once the gasket let loose, the spring popped the cap out against the screw heads, and immediately about a half-cup of water flowed out of the cavity followed by hydraulic oil. Mike was jerky about losing something down the gear shift hole, so we elected to remove the entire control block for a thorough inspection on the bench.

Once we had the control block on the bench, we used a sequence of gradually longer 5/16" bolts two at a time to slowly allow the pressure relief spring to relax and not launch the cover cap through the roof tin or into one of our jaws.

Removal of the cap exposes the heart and soul of the hydraulic system’s pressure control. The main components are the pressure relief valve, regulator valve, and the orifice plug and screen. There was a lot of crud everywhere. We pulled the regulator valve out of its bore to give it a look. IH provides a small nib on the piston so it can be gripped and removed from its bore. The piston and bore looked great, and its O-ring looked serviceable considering. The piston actuates a ball check valve, and its operation appeared flawless. There was nothing special to see when we looked at the pressure relief valve and spring. There are some specs in the manual regarding the spring’s free length and such. We didn’t bother with measuring. Oh, yes…it appeared to us that the pressure relief setting is non-adjustable unless a heavier rate spring is installed. Shimming the spring looked entirely impractical.

Most of the feedback from YT said to look for problems with the orifice plug and screen. The orifice plug is located very near the regulator piston, and its body is slotted. This was quickly threaded from its port with a large screwdriver helped out with a 5/16" wrench applying torque on its shank. Aha! Found the problem! The orifice was plugged with crap and corruption (one of Dad’s sayings) as well as the screen. In addition, the screen was collapsed or squeezed shut much like a flattened straw and was partially torn away from the orifice plug. I rodded out the orifice hole with a torch tip cleaner. This proved difficult as the blockage was stubborn.

I called the quasi-local Case-IH parts people and ordered the repair parts. They are available individually—a kit is not. Satisfied we had found the source of the continual high-pressure condition, we began to noodle out how the control works by spraying WD-40 into the various ports and watching where it came out. Here is our humble thesis:

Hydraulic system pressure from the pump must actuate the regulator piston so that the ball check is open at all times except when flow is diverted to a remote cylinder or the hitch cylinder. The regulator piston gets its signal to actuate by oil pressure coming through the orifice.  If the orifice and/or screen is plugged, the piston will not open the ball check to ‘unload’ the system. Failure to open the ball check results in the system being in a hi-pressure condition causing the pressure relief valve to 'dump' resulting in a squealing noise.  If pressure drops on the piston’s top side—actuating the fast hitch cylinder for instance—the ball check closes diverting pressure and flow to the cylinder. The small bore of the orifice controls the rate at which the regulate piston retracts and ball check closes.  The pressure relief valve protects the entire system, especially the pump, from damaging hydraulic lock.  The pressure relief actuates when a remote cylinder is held at full retraction or extension and when the regulator piston ball check fails to open.

Based on the above self-hypothesis, I concluded that the collapsing of the orifice screen occurred the instant the new hydraulic pump found its prime and began moving oil.  The screen and orifice were so dirty (some big surprise there!) that no oil could pass to the regulator piston side of things to equalize pressure on both sides of the screen.  Now that we had a pump capable of thousands of pounds of pressure, the screen smooshed in on itself.  I am very curious as to how long that 1/2 cup of water rested in the regulator valve cavity and how it got there.

All-in-all, what we examined was in pretty decent condition. I cleaned up everything to await the call from Case-IH. When notified of the parts arrival, I went to the store and was disappointed. Most of the parts that were tossed on the counter in front of me were unrecognizable. There obviously was a mix-up. Corrections were made, but I would have to wait a few more days for the correct items- the most important being the orifice plug and screen.

That following weekend found me itching to get the 460 back together despite not having the parts.  I DID manage to come home with a new regulator piston sealing ring and block cap gasket.  No more problem than it was to access the control pressure regulator block innards, I decided to fully clean the damaged orifice screen and reinstall it temporarily to see if progress was afoot. Bolting up everything else was a snap.  No gaskets are required other than for the cap—all other block surfaces have O-ring sealed ports--another nice touch by IH.  I have to add that considering the age of the system, the O-rings were in remarkably good shape.  Obviously quality components were used at the factory.  I should have replaced those O-rings while I was in there, but I saw no need: they didn't appear to have a problem, and they're easy to access if they do.

Everything was in place. Was this going to be it? I fired up the 460 and noticed immediately the high-pressure squealing was absent. Hooray! The hitch worked up and down just fine but…I noticed the tractor still was laboring. Not much but it still was.  I noticed the tach was indicating a low idle RPM of 300—much slower than the normal 500. RPM picked up when the hitch cylinder was actuated.  This isn’t supposed to be.  If anything, the RPM should drop some when the system is called on to do work—raising the hitch for instance. Mike seemed to think everything was OK at first, but the more he listened, the more he agreed with me that the 460 was laboring. Something still was not unloading the system.

The Fast Hitch system utilizes a feedback linkage IH calls Tel-A-Depth.  This linkage connects to the hitch lift cylinder and through a system of rods, lever arms  and shafts, a mechanical feedback signal goes to the Tel-A-Depth spool valve to tell it to shut down when a hitch height is selected.  The early versions of the Tel-A-Depth system used a cable—newer versions use a rod.  If this linkage is not adjusted properly, the hitch spool valve won’t get the proper signal to shut off, and the system will remain on high-pressure.  The I&T manual will step you through the procedures for making these adjustments and will step you through the many versions of the feedback variants that appear on the different versions of the IH 60 series family.

At right is a pic of the Tel-A-Depth feedback linkage adjuster.  The feedback rod has been broken and welded.  This happened prior to Dad acquiring the 460.  Bill informed me that for quite some time this rod was not even hooked up.  This certainly explains why the fast hitch had a mind of its own and wanted to "hunt" up and down.  Sure made for frustrating plowing.  Bill said he connected this one day and the height hunting stopped.

We made our adjustments to no avail. We couldn’t find that sweet spot where all the controls and linkage were in equilibrium.  Well, there is another place to look for the problem, and that is in the Tel-A-Depth spool valve itself.  There is another version of this control, but our 460 is equipped with the Tel-A-Depth differential gear box.  This is located within the spool valve body just behind the rear spool valve body cap. Two cap screws hold this in place.  I haven’t quite figured out how the gear box does what it does, but if the gears are damaged and/or the axles and pins for the gears are wacky, again the proper "shut me off" signal will not be relayed to the spool, and the system will remain on high pressure.  Sound like a broken record yet?

No problem with the gear box. It appeared as good as new. Well, what now? Disappointed and seething that this 460 was satanically cursed with a bad hydraulic system, I buttoned everything up and got some coffee. "You know, Mike," I pondered "this system hasn’t seen oil flows like it’s seeing now in decades.  We could be stirring up a bunch of crap inside the system.  That damaged orifice screen ain’t screening like it’s supposed to.   If that’s plugged up again…"

I deftly removed the orifice plug and lordy-be what do we have here?  Another chunk of deleterious material that Bill judged as being a wood chip was blocking the orifice!  I removed the gunk, assembled everything again and fired up the 460.  Something sounded better, and my eyes shot to the tachometer—500 RPM!  The hitch could be positioned at any height, and the Tel-A-Depth linkage did its job—no squealing, laboring or jerking.  I let out a whoop and hopped down on the floor doing a dance similar to Darrin McGavin’s winning a prize in the movie "A Christmas Story". At last, at last…free…at last!  I backed the 460 out of shop and ran it around the lot beside the shop whacking the throttle open just to hear the six-cylinder growl.  I also ran the Fast-Hitch up and down amazed at how smoothly it worked.  I parked it and walked back into the shop and was greeted by a smile from Mike. "Alright," he said. "NEXT!"

Some other notes: if the control/regulator block cap is removed to service the orifice plug and screen, a small amount of oil will escape.  There is no way to fill this area (regulator valve piston top) with oil prior to re-installing the cap.  Air is trapped in this cavity so initially a squealing, high-pressure sound will be heard.  This is the result of the trapped air being compressible and not transmitting the required hydraulic pressure to the regulator valve piston to fully unload the system.  Cycling the fast-hitch a few times will eliminate the trapped air.

Ahem…well there you have it. An almost complete step-by-step rundown of troubleshooting and repairing the 60 series hydraulics. The only thing I didn’t explore were the Hydra-Touch spool valves.  Finally after all this time, the 460 is getting its health back. I look on it with a sense of how strong it is now.  Before, I just pitied it and scolded myself for not tackling this problem sooner.  Dad would be proud.

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