801 hydraulic problem

[Clint(oh)]

Mowing grass over the weekend and all of a sudden my
3 point hitch wouldnt raise, when I started mowing it worked fine.
I can hear something coming from the hyd. pump when I attempt to raise the hitch but it is hard to hear over the engine noise.
I just bought this 801 powermaster 4 months ago and this is the first problem I have had with it, dont really know the tractor that well so any help is appreciated.
 

[Larry NCKS]

hydraulic oil level?
(dipstick by your left heel)

If Ok you have multiple possibilities, including but not limited to; failed pump, broken linkage, blown o-rings, blown pressure lines, etal.
 

[Clint(oh)]

The oil level is fine, and is there any way to rule
out one problem or the other?
 

[Larry NCKS]

This thought just occurred to me. Does it have a remote hydraulic valve? If so, might it be dislodged from the neutral position? A remote on demand will render the 3 point inactive.

One other thing you might check through the fill plug is for excessive oil spray in the compartment indicating leakage.
 

[Kurt-NEPA]

As Larry Said, Multiple possibilities here. Time to do some diagnostics.

Question, once the tractor cooled, is the lift working?

Three easy checks to make.

1. Make sure the Draft/Position control lever is in the Position control (horizontal) position.

2. Pull the round plate on the left side of the tractor. The one with the hydraulic dip stick. Start the tractor. Look inside with a flash light and mirror. Do you see any leaks near the cylinder opening. If you can lift, hold up some weight and turn the tractor off and check again.

3. Loosen the pipe plug on the hydraulic pump (just a little) and start the tractor. Do you see any bubbles? (Caution - gets messy, get a catch pan and rags). You may have to loosed the plug a bit more until you see oil, but don't remove it, If you do, you'll need many more rags. If you see bubbles, let them clear, then tighten he plug and check the lift.

These two step can identify the two most common problems. Blown piston O-ring and Piston pump seal leaks.

A third possibility is a broken cam follower pin or broken linkage. Checking that out involves removing the top cover.

Seem strange the lift would stop "all of a sudden" was it normal before it failed. Piston O-Ring and pump seal problems usually come on gradually. A broken cam follower pin would happen all of a sudden - This is my guess here.

Post Back
 

[souNdguy]

yes, systematic diagnostics.


now, back to larry's first question.. do you have any sort of diverter or remote valve fed off the top cover of your hyds cover. including power beyond 'sandwich' plates.

if not, then time to see if you have oil at the pump head by removing the plug in the top/front of the pump with engine off and run her over / crank.. if oil comes out.. stop.. put plug in, then remove plug under seat in 3x5 option cover and do same test.

if oil there.. then stop, plump in a 3000 psi gauge into that hole.. chain a lift arm tothe axle, and start tractor and run 3pt lever up ( if you have remotes you can also pressurize a remote with a hyd gauge in the lift port.. etc..

post back what she makes.

at this same time I'd hav ethe fill plug out and using a strong led flashlight and a mirror , look in to see massive oil spray / squirting going on from anywhere inthe top side.... especially if the psi made on the gauge is lower than 2100 psi..

also note if running the lift up whiule chained labors the engine any.


ps.. if it has a proofmeter.. is it working?

post back
 

[Clint(oh)]

The tractor doesnt have any remotes, and when I initially started the tractor to mow I raised the deck, everything was fine,got to the area to be mowed and lowered the deck and everything was fine. Within 10 minutes I had to cross the driveway with the mower turning went to raise the deck and nothing.
I will pull the plugs and see if oil comes out and check the psi as well and report back, but it is weird that it just all of a sudden happened.
 

[souNdguy]

if you have depth limit chains holding the deck at cutting height .. then it's also possible the unlaoding valve has simply stuck as well...
 

[John-30]

I had the hydraulics quit on my 801 diesel and here is what I found. My tachometer stopped so I knew the problem was at the pump. The inner splines on the drive gear had stripped. The parts man at the dealer has been around forever and he informed me that worn timing gears causing too much backlash contributes to this and the diesels are much worse than the gas models. With the problem I had getting the timing right after a fuel pump overhaul, he may be on to something. This winter I'm going to tear the front off the engine and see what kind of shape the gears are in. This tractor has been in the family since 1971 and never been apart. Sound likely I think. Hope this helps someone.
 

[Kurt-NEPA]

Wow! John, I've heard of stripping the gear to wobble shaft splines before, but its one of the last things I would have expected. At least its not too bad of a fix.

Are you going to attempt the pump rebuild? If yes, I've done mine and can give you some pointers if you want them. If you have a shop press and some mechanical background, its not too bad of a job. I think most everything is available after market. I'll have to check on the gear.
 

[John-30]

Kurt, if you are referring to rebuilding the hydraulic pump, that was not necessary. I only replaced the drive gear, and it was in stock! Less than $100 for gear, o-rings and a gasket.
 

[Kurt-NEPA]

John, You got lucky, Only the gear was stripped. Good news! Just wrench turning that way!