Getting ready to do hydraulics

[grhouse]

I'm getting ready to do the hydraulics, due to very weak lifting power, and watched a video about it and read the shop manual and though that it wouldn't be much more expense to put in a Valve Chamber Repair Kit while I had the fluid out and it isn't too expensive (about $50). But, I've generally said, "If it isn't broke, don't fix it".
My question is: Should I look at this as a sort of preventive maintenance and go ahead and do it and save on the cost of possibly having to do it later and replace the fluid again? This is a 1950 8N front mount.
Of course if I put the chambers in I have to pull the PTO and it would be a good idea to replace the shaft bushing, seal, and gasket while I am at it so I can add another $25 or so.
All thoughts would be appreciated. Gene

 

[Gramps in NM]

I can only speak in generalities as I'm no authority on the N's. It has however in all aspects of maintenance been my policy/experience that if you are at a certain point and it only takes a little more money/time to do the whole works---- Do the works!!!

 

[Plane Bart]

If you have it apart and have play at the PTO bearing I would deffinetly replace it.
I just rebuilt my pump on my 9N probally could of got away with just new Pump relief valve and control valve but decided to rebuild the pump while it was out.
the new land of the lost rebuild kits were not that great the cam blocks would not work to thick to let the pistons seat.
on trick I learned was to use a Torx T-25 driver to pull out the sockets from the pump chambers mine were stuck at the bottom.
also new relief valves do no look anything like the original ones.
good luck.

 

[rmlarsen]

I agree with Gramps in MN. My maintenace philosophy has always been to consider the amount of time to get it apart and put it back together. If more than a few momeents, fix or at least inspect any wear item while you are in there. You don't want to spend several hours a second time replacing that $2.00 seal you could have replaced the first time. My $0.02 worth!

 

[TheOldHokie]

(quoted from post at 16:22:42 07/12/10) I'm getting ready to do the hydraulics, due to very weak lifting power, and watched a video about it and read the shop manual and though that it wouldn't be much more expense to put in a Valve Chamber Repair Kit while I had the fluid out and it isn't too expensive (about $50). But, I've generally said, "If it isn't broke, don't fix it".
My question is: Should I look at this as a sort of preventive maintenance and go ahead and do it and save on the cost of possibly having to do it later and replace the fluid again? This is a 1950 8N front mount.
Of course if I put the chambers in I have to pull the PTO and it would be a good idea to replace the shaft bushing, seal, and gasket while I am at it so I can add another $25 or so.
All thoughts would be appreciated. Gene

We can argue the quality of the current crop of replacement parts until the cows come home. The value of replacing old worn parts with fresh new ones of reasonable quality versus a spit shine of old worn parts is not arguable.

TOH

 

[dont_know_a_thing]

I would replace anything that you could while you was doing it now. More then likely you'll never have to worry about it again for a long time...

I was always told if you don't have time to do it right the first time, you must have the time to do it over later....

 

[ZANE]

What makes you think working on the valve chambers will make the lift stronger? That is the last place I would start. First I would replace the pressure relief valve and maybe the piston rings.

Do my lift trouble shooting first and then proceed.

TROUBLE SHOOTING THE 8N HYDRAULIC LIFT

BEFORE DOING ANYTHING TO THE LIFT IT SHOULD FIRST BE INSPECTED FOR ANY INTERNAL LEAKAGE. GOOD ADJUSTMENT CAN BE DONE WITH A LEAK IN THE SYSTEM BUT FOR GOOD OPERATION AND IN ORDER TO TAKE FULL ADVANTAGE OF GOING INTO THE LIFT IT SHOULD BE DONE FIRST BEFORE ANYTHING ELSE IS DONE.

BE SURE THAT THE LIFT IS FULL OF OIL AND THAT THE OIL IS CLEAR AND HAS NO WATER IN IT. WATER CAN CAUSE FREEZING AND VALVE SEIZINGS ETC. NOT GOOD!

BE SURE THAT THE PTO IS ENGAGED UNLESS YOU HAVE ONE OF MY LIVE HYDRAULIC DEVICES WHICH WILL ALLOW YOU TO USE THE THREE POINT HITCH WITHOUT THE PTO IN OPERATION OR THE CLUTCH ENGAGED.

THERE IS ALSO THE REMOTE POSSIBILITY THAT SOMETHING IN THE PUMP DRIVE MECHANISM IS BROKEN SUCH AS THE SCOTCH YOKES THAT THE PISTONS ARE ATTACHED TO.

TAKE OFF THE RIGHT SIDE INSPECTION PLATE THAT HOLDS THE DIP STICK FOR THE DRIVE TRAIN OIL LEVEL AND START THE TRACTOR WITH AN IMPLEMENT ON AND LOOK FOR A BAD LEAK COMING FROM ABOVE OR THE ABSENCE OF MOVEMENT IN THE CENTER OF THE PUMP AREA. IF NOTHING IS MOVING IN THE CENTER OF THE PUMP AND THE PTO IS TURNING YOU PROBABLY HAVE SOMETHING MAJOR BROKEN ON THE PUMP. YOU CAN LET OUT ENOUGH OIL TO SEE THE MOVING PARTS OF THE PUMP TO BE SURE WHEATHER OR NOT IT IS IN FACT WORKING OR NOT. HARD TO TELL WHEN COVERED BY A COUPLE OF INCHES OF OIL.

I think that you are probably having a combination of problems which is common to the 8N lift. One of the worst offenders when it comes to the adjustment is the cam follower pin which is what the position control receives it's input from. If it is badly worn the lift can’t possibly work right until it is replaced.

The other thing is to look for a leak in the system @ the ram cylinder rings etc and the pressure relief valve. Also there could be a gasket leaking somewhere such as under the ram cylinder where it mates to the lift cover housing.
If you decide to take the lift off to work on it be sure not to remove any bolts or nuts except for the ones around the outside perimeter of the cover. If you should remove a bolt that has fine threads it will be from the inside pattern and you should put it back in the same hole it came from. You can remove them after the cover is on the work bench if it becomes necessary to remove the ram cylinder for repair.

When the lift won’t come down it is a sure sign that you have dirty oil in the hydraulic reservoir or that the return spring which is under the intake valve is weak and needs to be replaced or stretched out again to increase it’s tension.

EXHAUST CONTROL VALVE SPRING DAMAGED OR MISSING
There is a more rare condition that will really put a monkey wrench into the operation of the lift on the 9N/2N AND OR 8N. This is when the retaining spring that is an integral part of the exhaust control valve breaks or becomes too weak to actuate the exhaust valve when it is moved by the control linkage. The spring is located on the exhaust valve itself and has to be intact in order to move the valve when the linkage is moved. It may be necessary to pull the pump in order to inspect and repair the exhaust control valve.

134 oil is great but it can make a small leak worse because of it being a lot less viscose.


You should first take off the right hand inspection plate under the seat on the side of the lift housing. First inspect everything by eye and with a mirror to look at the upper parts for any obviously damaged parts. Move the touch control handle and observe if the control valve is moving in and out of the pump. If the valve is stuck you may be able to get it to working by moving it back and forth with the hand inside the housing till it is loose enough to move with the touch control only. With an implement on the lift start the engine and with the lift in the up position look inside and see if their is oil leaking from the end of the lift ram cylinder. If their is only a slight drip this is normal. If their is a fairly steady stream this may be the trouble. If the oil is coming from somewhere else try to pin point its origin. If you find no appreciable leaks on top in your view then you may have a pressure relief valve leaking. It is located just under the PTO shaft on the vertical back of the pump .Sorta shaped like a spark plug and an 11/16" box end wrench fits it. You can check it for leakage by first finding it with the engine off and then with the pump running and with a load and hot put your finger over the end of the relief valve and if it is leaking enough to be a problem you will be able to feel the oil push your finger off the end of the valve slightly. You can check it by first removing it from the pump then washing it up and soaping it real good with some dishwashing detergent and water and apply air to the end that goes into the pump. If it is leaking you should replace it with a new one. The part # used to be 8N638.

There is always the remote possibility that the pump housing is cracked. This ain’t good! To my knowledge a cracked housing is just about done. The cracks usually appear where it is impossible to get to weld and the housing must be replaced. Don’s Just 8Ns has them I think or could tell you where to find one if needed. I have a method for testing for a crack. I tapped the outlet pressure hole to accept a 1/4" pipe thread so a grease fitting can be screwed into the outlet hole in the pump flange. Use a grease gun to pressurize the pump with the control valve pushed in to the up position and observe if the grease gun can continue to be operated slowly until the relief valve allows grease to escape out the end of the relief valve. If it can’t be pumped up enough for the relief valve to open then look for grease escaping somewhere behind the relief valve and usually under the pressure chamber behind the relief valve. This is a crack if it shows grease escaping anywhere else in the housing and can't be fixed to my knowledge because of the placement of most cracks I have seen in the N pump.
The housing must be replaced usually.
There could also be a gasket blown out and leaking. If it is in the upper portion of the lift you will be able to see the oil streaming down and this will give you some idea of where it is coming from. Then you can fix it when you get into the cover. Sometimes the pump gasket itself can blow out where the pressure line inters the lift housing on the bottom of the housing. When it blows inside it is just about impossible to determine what the cause is of a very weak lift until the pump is pulled from the tractor. If no other source of a leak can be found it is always possible that the pump gasket has failed internally. The only way to fix it is to remove the pump and clean both the mating surfaces of old gasket material and replace the pump after cleaning with a new gasket and hope for the best.
The side pump chamber gaskets can blow out too causing a slow throbbing lift.

Hope this will give you some starting places. Zane in Al.

If the lift does not lift to the top of it’s travel when the touch control handle is raised all the way up then you have linkage problems. Wear and or abuse can bend and wear parts of the linkage to cause this condition.
If the lift needs to be adjusted you will need instructions and a jig to allow you to do the adjustments.

See my web site at
http://my.att.net/p/s/community.dll?ep=16&groupid=220626&ck=

 

[grhouse]

I guess I should have pointed out that I am changing out the ram piston to the NAA530B and the Relief Valve since those seem to be the most common problems. But I will be looking through the access panel first to see if there is any visible leakage. If there is no visible leakage then I'll remove the top cover to replace those two items.
I've already got Zane's Jig and cam follower pin and plan to carefully follow those instructions for alignment.
My question was to determine other member's thoughts about going ahead and do the chambers and PTO seal, bearing, gasket, and bushing while I had the fluid out of the tractor and partially broken down as a preventive maintenance step. The total for additional parts for the chambers and PTO will run about$80.

Another question: Do I need someone to help me get the hydraulic off and reinstalled. I was told it weighs about 100# and has a rod that must be put precisely into a socket at the bottom. I had planned on using a shop crane and webbing to lift it and reinstall it. I can let the crane down very slowly while I am guiding the rod into the socket.
To drop the pump, I would use a platform attached to a floor jack.
Of course, if I find severe scoring or anything cracked them I'll have to stop and order additional parts or try to repair what is broken. I do have a neighbor with a machine shop about a mile away.
As an aside, I do wish that the pictures in the Zane guide were clearer and easier to follow. I think I'll make some pictures while I'm doing this and make them available here on-line. Gene

 

[ZANE]

You still have not addressed the pressure relief valve's condition???? This is the most common item to give problems with a weak lift. Unless a spring is broken in the valve chamber there is little chance of it being a problem and even if a spring is broken it will only effect that one cylinder and will not effect the lifting power to any degree. It will just cause the lift to chatter or pulse as it raises and will not cause any leakdown.

Zane

 

[grhouse]

I plan to replace the Pressure Relief Valve along with the Piston since these are the two most common problems. I will have to determine if there are more issues after I take the inspection plate off and look at it.

My main question here was simply if the members thought I should do the chambers as form of preventative maintenance since I am going to have the tractor down and the fluid out anyway.

As an addition to that, if I am going to pull the pump to clean and do the chambers then I have to pull the PTO (no problem) and I can replace a leaky seal and gasket there and if I go that far go ahead and replace that$6 bearing and bushing.

Of course, after I open up the inspection plate I may see issues that suggest a different plan of attack but I don't think so. The lift will bring a double 14" plow up with no problem and will lift a King Kutter Bush Hog off the ground. It will not lift my 550# disc. Therefore I do not think it can be anything major and believe it is probably just the Pressure Relief Valve. But if I have to open it up I'll change the piston and cam follower pin and do whatever else needs to be done so that I don't have to open it again (hopefully) during the next 15 years or so after which it probably won't matter since I'm 60. Of course, everything depends on actually looking at the parts.
The reason I'm asking these questions is so that I can go ahead and buy the parts I think I'll need so that when I do open it up I won't have to wait for parts if the only issues are the ones I believe it to be based on everything I've read in this Forum. Gene

 

[DollarBill]

[color=darkred:220d63c625][b:220d63c625]All thoughts would be appreciated[/b:220d63c625][/color:220d63c625]

Gene, my two cents here.... I wouldn't order parts until I had it apart.

I also prefer original parts that worked over shiny, new, furran junk.

When you reassemble it, put the lift cover on first and then install the pump - It's easier to line up the control rod laying on your back than from above.

You will be doing yourself a favor if you troubleshoot the problem before disassembly.

 

[ZANE]

A 550# disc is too much for it to lift even in top condition. Most of the disc is way behind the ends of the lift arms and that is where it is capable of lifting 550# Not way back there. Way too much leverage.

Zane

 

[Hobo,NC]

You can man handle the cover are the pump,,, that's the way I do'em.... a engine lift does take a lot of the pain out of it,,,, NO you do not have to nail the rod to the socket,,, you can lift the rear of the cover once its laid in place and reach in and guide the rod into the socket,,, a couple of guide pins help,,,,are install the pump with a few bolts in the front by a few threads and reach in and guide the rod in the socket,,,its a one man show,,,, theirs nuttin to it (8N)if you are a man

 

[grhouse]

I really should have thought of putting the cover on first and then putting the pump in. That makes a lot more sense. D***, this epilepsy medication the doctor has me on really messes with my thinking. Thanks for that time and trouble saver. Gene