80s Satoh Bull Tractor Hydraulic Problems

[mattg781]

Keep in mind, I don't know much about tractors, especially hydraulics...but I know how to turn an wrench and apply techniques to put things back together.

Anyhow, I am going to make this short. Tractor was lifting 3 point fine after it sat up for 15 years. I added #80 gear oil to the fill plug and checked it with the check plug. 3 point started working again then stopped. Drained fluid, cleaned filter screen, and added new fluid. Still no go. So I parked it.

-Checked valve on top of hydraulic plate. Bolt, piston, spring, O ring, etc looked fine. Nothing clogged.

-Took off top hydraulic plate (see pics). Took Valve off and two bolts holding valve and springs in. Everything looked OK. Maybe I should have inspected it further.

-Reassembled and still nothing.

-Loosened hydraulic pressure (?) line, cranked engine...fluid came out fine. So I guess pump is primed and working.

-Loosened bolt on other side (feed to piston?), nothing came out.

-Tried adjusting control lever on top...nothing. I'm stumped. Maybe I need to remove top plate again check those valves because I am assuming hydrualic fluid should be going from left side (feed) to right side (goes to piston chamber?).

Thanks!

 

[mattg781]

I also used an air compressor to make sure any hydraulic line was free. I am guessing maybe there is a stuck piston inside that valve chamber possibly? Any tips would be awsome as I am learning so much playing with Dads old tractor

 

[mattg781]

One last thing. Only thing I didn't check was a flat head screw that fit flush. I didn't unscrew it, but maybe this could be the culprit.

 

[Rock knocker]

80w? Most trans/hydraulic sump combos take a substantially thinner oil.

 

[4570Man]

I'm pretty sure you should have used hydraulic oil which is 20w.

 

[Leejohn]

There is some O rings under the valve, if one is leaking it might not get pressure to the piston.

 

[Dave M7040]

I too think you used the wrong oil. Likely clogged intake screen/filter for pump.

This site sells manuals for $30

Mitsubishi tractor manuals to download

Might be a good investment so you know what to use and how much you need.

Kubota UDT fluid would be my choice if I was going blind.

Dave M7040

 

[mray16]

Well I changed out my hydrolic/transmission oil on my satoh s630d and used tractor supply universal 10-30 hydrolic.transmission oil, and it will try to lift but stops. just looking at manuel and it calls for 80 weight gear oil. I think i have found my problem.

 

[mray16]

Well oil not the problem, valve was stuck in the control , sludge and metal particles, guess i'll take control and piston apart and clean everything.

 

[kbjorn]

You guys ever get your stuff working? I'm in the middle of this now, about to tear it apart further but trying to check simple stuff first. Took apart flow control, cleaned changed orings (close as I can get em?)/ Checked relief valve. Ordered guage-- be here Monday.

Manual says to let it run 30 min before testing. I have lift on 3 pt but not if its loaded. Bleed procedure poorly described in manual. But this seems to keep getting air even after being bled? Maybe I just gotta run it longer?

Inherited this tractor and it sat outside with cracked boot on tranny for years, I have changed oil/water one time. going to flush and try again. Definately milky/ cruddy at round one. Thought about putting a splash of diesel in oil but then realized i might blow up pump

Isn't learning fun?

Looking like I need a total overhaul. it seems fairly well described in manual. well actually the manual is more riddle than anything. But the line " if oil is in good condition" kind of has me at a stopping point. at 100$ an oil change, i thinking i should pressurize or vaccuum the system.