1955 PTO Issue

Cash4Toys

Member
Hoping that someone has some insight into this PTO issue. Bought this a few months back, 1955-2516xx, had some issues with the hydraulics, which case they have all been resolved. Started with the fact someone replaced the unloading valve, and the excess Teflon tape was all bound up in the pressure valve (s) spools. Removed and cleaned, replaced all the O-rings, run the tests and pressure's were reset, low pressure side as well. Thought maybe this was a cure for the PTO to be able to be stopped by hand. No help. Teed a gauge in at the pressure line on the PTO valve, plugged the return line to the reservoir, engage the PTO, had 0 lbs pressure. Found that the pressure line that feeds the junction block on the low pressure side had rubbed on a cooler line, wore a hole but didn't leak to the outside. Replace the line, now have 240 psi at the valve teed in, still won't run. Valve engages the clutch, minor leakage from the return line when engaged, and the brake will hold when applied. Pulled the pto, pulled it all down. Clutch discs looked as "new", and measure within new specs, both friction and the steel. Thrust bearing and plates show "0" wear, not even a wear pattern. Did a mag particle on the clutch and brake housing, no cracks or holes.
Have reassembled the darn thing, but I haven't really fixed anything, so where do I go from here? Don't really want to put it back in knowing nothings changed. pretty sure I must have missed something simple, so maybe someone can point out where I went wrong. It is 2 speed, and in 540 with 540 shaft now.
 
I would check the 2 snap rings in the control valve (#14) page 103 in the parts book. Seen them break before and cause the same problems your describing
 
I had the apart, cleaned and inspected the parts. Spool and no signs of marring, with exception to the area that the ball for the detent rides. The sleeves, both the 13/16" and 3/4" looked good, fine scar on the smaller one, cleaned up the scar with 420 grit easily.
No where have I found, nor has anyone been able to tell me how the bolt and lock-nut of the bottom of the valve actually is to be adjusted. Not discussed in my original Oliver service manual at all. It goes against the "feel" disc. Question? If in "neutral", there should be no oil returning to the reservoir, per the service manual. Then when you engage the PTO the spool moves upward, and the detent ball comes into play once the pressure increases. To apply the brake, the spool moves downward from neutral. So, laying on the bench, the spool is bottomed out. Does this mean then that "neutral" is a point where the oil pressure centers the valve/spool in neutral?
 
Pretty sure you should have no oil going to return when operating. The return line is for the pressurized oil to escape when the pto is put in neutral or off. If you plug the return line when the pto is engaged is should work properly. You should be able to use regular shop air the pressurize the clutch pack and look for visual leaks or listen for leaks....I still think the problem is in the valve.
 
(quoted from post at 15:16:20 12/27/18) Pretty sure you should have no oil going to return when operating. The return line is for the pressurized oil to escape when the pto is put in neutral or off. If you plug the return line when the pto is engaged is should work properly. You should be able to use regular shop air the pressurize the clutch pack and look for visual leaks or listen for leaks....I still think the problem is in the valve.

I agree with that statement. Per the service manual, as you engage the PTO oil pressure will compress the spring thus allowing the sleeve to close the return oil port. The service manual also says that in neutral, the port is closed, and there should be no return oil. When you apply the brake, the spool is pushed down and the oil goes to the brake cylinder. I still don't quite get this part, as I stated the spool is bottomed out as it lays here on the bench, so how do you lower the spool to apply the brake? Does oil somehow center the spool with pressure? There is friction plate or anything on the linkage to hold it mechanically, so I don't understand this part of it.
The valve is assembled as it illustrated in the parts book as well as the instruction's in the service manual. On the bench, air will apply the clutch and the other port will apply the brake. I did replace the quad-rings by the way, and really saw nothing wrong with the old.
 
(quoted from post at 15:47:31 12/27/18)
(quoted from post at 15:16:20 12/27/18) Pretty sure you should have no oil going to return when operating. The return line is for the pressurized oil to escape when the pto is put in neutral or off. If you plug the return line when the pto is engaged is should work properly. You should be able to use regular shop air the pressurize the clutch pack and look for visual leaks or listen for leaks....I still think the problem is in the valve.

I agree with that statement. Per the service manual, as you engage the PTO oil pressure will compress the spring thus allowing the sleeve to close the return oil port. The service manual also says that in neutral, the port is closed, and there should be no return oil. When you apply the brake, the spool is pushed down and the oil goes to the brake cylinder. I still don't quite get this part, as I stated the spool is bottomed out as it lays here on the bench, so how do you lower the spool to apply the brake? Does oil somehow center the spool with pressure? There is friction plate or anything on the linkage to hold it mechanically, so I don't understand this part of it.
The valve is assembled as it illustrated in the parts book as well as the instruction's in the service manual. On the bench, air will apply the clutch and the other port will apply the brake. I did replace the quad-rings by the way, and really saw nothing wrong with the old.

The only thing left that I did not look into before I took the PTO out of the tractor, was to see if by chance the linkage/lever was bottoming out on the console, preventing full upward travel. Clutch and brake operate fine laying on the bench with air applied, so I guess I going to have to put it back in and look for some issues elsewhere, be it linkage or valve, which case I should not have to remove the whole darn thing. Would you not agree?
 
Yes I would agree....it's usually the simple things....you may also have some play in the lever that pulls the valve up (the roll pins wear with age)?.don't be to hard on yourself for removing the pto unit. I've gone through the same problem on a 2-105....if you have access to a 2-85/2-105 shop manual the pto section is far and away better than the "55" series manual and has all the updates (to that point of manufacture) listed. The adjusting bolt on the bottom of the valve is for "feel", ie, the resistance your hand has against it at the point of clutch engagement. Because the pto clutch is hydraulic, there is no resistance on your hand as there is on a manual clutch (the caming over), so this adjustment is to create some increased force at the same time the pto engages so the operator can slightly "ease into it"
 
There really is no detent in the on position. Hydraulic pressure keeps the spool in the one position. Thee is a slight detent in the off position to hold the lever/spool there. Moving the lever off to neutral to on postion, all you will feel is pressure against the lever wanting to return it to the off/neutral position. Also, is the 540/1000 pto fork totally engaged and locked? The bolt on the bottom of the shifter should be in a small detent hole in that shifter.
 
(quoted from post at 19:02:39 12/27/18) There really is no detent in the on position. Hydraulic pressure keeps the spool in the one position. Thee is a slight detent in the off position to hold the lever/spool there. Moving the lever off to neutral to on postion, all you will feel is pressure against the lever wanting to return it to the off/neutral position. Also, is the 540/1000 pto fork totally engaged and locked? The bolt on the bottom of the shifter should be in a small detent hole in that shifter.
I had that section apart as well. Replaced the seal(s) and inspected the bearings. Both bearings and their race show no sign of wear. Also confirmed that the safety pin was working for the 1,000 side of the spline/shifter collar and all is good. replaced the seal on the shifter fork as well. Double checked it when it was altogether, works fine
 

You say the newer 2-85/105 service manual covers this better than old 55 manual. I will just buy the manual and read through that as well. Thought about it anyway, bought the "hydraulic" part of it to get the pressure valve figured out.
My PTO valve diagram still shows a spring and ball on the detent, and yet the parts book does not even list a spring and ball. Took a while to get around that. Oh, and that's another thing, 18/19/2255 parts says the piston for the detent uses a 1/2" x 1/16" O-ring, 85/105/88/110 says it is a 3/8" x 1/16" O-ring. 1955 is kind of a Heinz 57, parts says it should have same rear axle housing (s) and axles, bolted inner retainers and bull gears same as 1950T & 2050/2150 non planetary, but in fact it has 2-105 housings, axles and gearings, and this one has the later style "snap ring" inside retainer. For sure you don't order anything until you have the old part in your hand.
I don't know what to think, maybe I overlooked the obvious when I pulled it down, guess I will put it back in and try it. If it works, gonna buy a lottery ticket same day!
Appreciate your time here, thanks!
 
Are you sure the 2 hydraulic lines are hooked up to the right PTO valve ports?
There where some upgrades to the PTO valve over the years.
On the last 1855 I bought the PTO lever did not want to hold in either the On or brake position,.turned out there was a poppet valve missing that goes between the valve and the PTO housing.
That poppet valve does not exist on my other two 1855's
 
(quoted from post at 13:02:35 12/28/18) Are you sure the 2 hydraulic lines are hooked up to the right PTO valve ports?
There where some upgrades to the PTO valve over the years.
On the last 1855 I bought the PTO lever did not want to hold in either the On or brake position,.turned out there was a poppet valve missing that goes between the valve and the PTO housing.
That poppet valve does not exist on my other two 1855's
This one has the detent plunger in it with a ball. It holds the spool up when PTO is engaged. Service manual says it was a spring and ball, shows in the breakdown in the service manual, but there are no part numbers for it. Discrepancy in the parts books from the 55 series to the 85-110 series as to the O-ring size, so I am installing a new one with the latest version, poppet and O-ring, but I don't believe it will change anything. It is rebuilt now, works good with air on the bench, with out the valve installed. Air pressure must not be adequate to operate the valve, as it just by passes and exhausts. When I took it apart, all of the quad rings looked to be in good condition, so I just don't quite get it. I assumed that when the pressure line started to leak through the hole worn in it, the clutches started to slip and were just worn out or burnt up, but they were just like new. I am going to put it back in and hope for the best.
 
Our 2-150 that is newer than the 1955 has no detent in the on position. Hydraulic pressure holds it there. With the engine off the pto lever will not stay in the on position unless hydraulic pressure holds it there. If Pressure drops below about 160-170 psi and you tap a brake the pto may shutoff unexpectedly when pressure drops too low. That detent is for the off position not on. You actually have to hold the lever front long enough for hydraulic pressure to build and hold the spool in the on position, and no air pressure will not be enough to hold it in the on position.
 
(quoted from post at 09:56:11 12/29/18) Our 2-150 that is newer than the 1955 has no detent in the on position. Hydraulic pressure holds it there. With the engine off the pto lever will not stay in the on position unless hydraulic pressure holds it there. If Pressure drops below about 160-170 psi and you tap a brake the pto may shutoff unexpectedly when pressure drops too low. That detent is for the off position not on. and no air pressure will not be enough to hold it in the on position.


(You actually have to hold the lever front long enough for hydraulic pressure to build and hold the spool in the on position),

You are correct.
On all 3 of my 1855's I have to hold the lever forwards for a few sec before it locks in.
 
(quoted from post at 08:28:20 12/29/18)
(quoted from post at 13:02:35 12/28/18) Are you sure the 2 hydraulic lines are hooked up to the right PTO valve ports?
There where some upgrades to the PTO valve over the years.
On the last 1855 I bought the PTO lever did not want to hold in either the On or brake position,.turned out there was a poppet valve missing that goes between the valve and the PTO housing.
That poppet valve does not exist on my other two 1855's
This one has the detent plunger in it with a ball. It holds the spool up when PTO is engaged. Service manual says it was a spring and ball, shows in the breakdown in the service manual, but there are no part numbers for it. Discrepancy in the parts books from the 55 series to the 85-110 series as to the O-ring size, so I am installing a new one with the latest version, poppet and O-ring, but I don't believe it will change anything. It is rebuilt now, works good with air on the bench, with out the valve installed. Air pressure must not be adequate to operate the valve, as it just by passes and exhausts. When I took it apart, all of the quad rings looked to be in good condition, so I just don't quite get it. I assumed that when the pressure line started to leak through the hole worn in it, the clutches started to slip and were just worn out or burnt up, but they were just like new. I am going to put it back in and hope for the best.

Don't forget the 2 small 0 rings between the 2 castings of the PTO housings. :wink:
 
(quoted from post at 09:56:11 12/29/18) Our 2-150 that is newer than the 1955 has no detent in the on position. Hydraulic pressure holds it there. With the engine off the pto lever will not stay in the on position unless hydraulic pressure holds it there. If Pressure drops below about 160-170 psi and you tap a brake the pto may shutoff unexpectedly when pressure drops too low. That detent is for the off position not on. and no air pressure will not be enough to hold it in the on position.


(You actually have to hold the lever front long enough for hydraulic pressure to build and hold the spool in the on position),

You are correct.
On all 3 of my 1855's I have to hold the lever forwards for a few sec before it locks in.
 
(quoted from post at 10:12:18 12/29/18)
(quoted from post at 08:28:20 12/29/18)
(quoted from post at 13:02:35 12/28/18) Are you sure the 2 hydraulic lines are hooked up to the right PTO valve ports?
There where some upgrades to the PTO valve over the years.
On the last 1855 I bought the PTO lever did not want to hold in either the On or brake position,.turned out there was a poppet valve missing that goes between the valve and the PTO housing.
That poppet valve does not exist on my other two 1855's
This one has the detent plunger in it with a ball. It holds the spool up when PTO is engaged. Service manual says it was a spring and ball, shows in the breakdown in the service manual, but there are no part numbers for it. Discrepancy in the parts books from the 55 series to the 85-110 series as to the O-ring size, so I am installing a new one with the latest version, poppet and O-ring, but I don't believe it will change anything. It is rebuilt now, works good with air on the bench, with out the valve installed. Air pressure must not be adequate to operate the valve, as it just by passes and exhausts. When I took it apart, all of the quad rings looked to be in good condition, so I just don't quite get it. I assumed that when the pressure line started to leak through the hole worn in it, the clutches started to slip and were just worn out or burnt up, but they were just like new. I am going to put it back in and hope for the best.

Don't forget the 2 small 0 rings between the 2 castings of the PTO housings. :wink:
I replaced them.
Just did a bench test on this, took one of my 3" x 8" cylinders, stroked it out with another tractor, so the piston side had all the oil. Disconnected it, then reduced the rod end down via Pioneer coupler, etc down to my air chuck fitting. The piston end I used another coupling and reduced down to the flare fitting, teed in my gauge. Put an air regulator on it, dialed in my 225psi with about 33 psi air, operated the valve by hand and it seems to work fine. Now I placed a 1/4 turn valve in the exhaust port, left pressure on it, for about an hour or so on the clutch and the same on the brake, with no leakage, clutch or brake.
Of course there is no way I can tell if will "pull", but at least I know the clutch and brake are good.
I went ahead and bought the 2-85, 105 & 150 service manual, and in there it said to use another tractor with a 200 psi system to test this, so I improvised. The 1/4 turn valve is so I could let the clutch or brake exhaust when I switched them.
 

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