L3600 GST Hydraulic Problem

[coderbond]

Okay, This isn't really a new problem as much as a.... assembling for the first time problem.

A little back story, I bought this L3600 GST that was partially disassembled by some nose candy loving meth head. Basically the owner found the tractor being stripped, took it to the local Kubota shop and the price to fix the tractor was such the owner just bought a new. The dealership sat on the tractor for about 5 years and finally decided to sell it.

I bought it with no top cover or instrument panel. The tractor sat with no top cover the whole time, they threw some cardboard over it and duck taped it down. I took the mid PTO shaft off and ran about 45 gallons of diesel through the transmission, rear diff and what not using a sprayer. I cleaned it up as best I could.

Fast forward 6 weeks and I've re assembled the tractor.

My knowledge falls short when it comes to hydraulics and that's what I'm dealing with now.

Basically, when I started the tractor the 3 point worked, or lifted once anyway. It doesn't work any more, I loosened the knob under the seat and it went down. I've tightened back up and still nothing from the 3 point. The loader gets jerky after using it for a couple minutes. The tractor doesn't drive, I can feel the transmission engage slightly and try to roll when I place the speed selector in 3 or 4 and push the shuttle into forward or reverse but it just kind of lurks forward. When the transmission is engaged I loose almost all steering, sometimes it just free spools and other times it's jerky.

So, after all this, I cracked the hydraulic filter and got a considerable amount of debri from the filter. I screwed it back on and ran through moving the all the hydraulic components and cracked the filter again, more of the same. I didn't this about a dozen times until I stopped getting crap in the filter. I drained the forward transmission and got more debri, I drained the mid case and got more debri. I drained the whole system, rinsed and repeated. At this point I've been running the fluid through strainers to clean it before putting it back into the system. Last night I threw a new hydraulic filter on it, same problem.

I have planned to do a complete swap of the fluids once I'm sure things are working.

After doing all this I'm still having hydraulic problems throughout the entire system. Is there a pickup screen, pressure relief valve, bleeders valves or something I should be checking now?

I've ordered a shop manual and an owners manual, they're on their way.

a little tractor porn.

 

[North Idaho Wolfman]

GST's rely on hydraulic pressure to do everything, so the #1 thing you're going to need to get is a good hydraulic pressure gauge setup.
You can get the gauges off of EBay (http://www.ebay.com/itm/New-Hydraul...ic_Hydraulic_Valves_Parts&hash=item3a8e26c699) get a couple in 0-500, 0-3000 are good ranges, get a grease gun whip (hose) and a 1/4" female pipe to 1/8 female pipe adapter, and then you will need to get a 1/8" BSPT to 1/8"MP adapter:
http://shop.hoseandfittings.com/catalog/Fitting/Steel/Metric_-_British/Straight/MBSPT-FP.html
This setup will allow to test the pressures that are needed for the system to work right.

 

[coderbond]

Hey, Thanks for the reply.

Can you look over my cart, make sure this is what I need.

http://www.amazon.com/gp/registry/wishlist/3R0HCFASJQ5VQ/ref=cm_wl_rlist_go_o

 

[North Idaho Wolfman]

Change the second fitting to female to female and 1/8" NPT to 1/4" NPT and you've got it!
That fitting connects the whip to the gauge.

 

[coderbond]

Okay, Cool~

Next question, where do I hook it up and what kind of pressures am I looking for?

Thanks Again, BTW.

 

[North Idaho Wolfman]

When you get the service manual it will point out all the locations and pressures to look for.
There are 8 different locations on my model to test.

 

[coderbond]

I pulled the pickup tube and verified its clear of obstructions, There's no pre-screen in the system either. But sounds good though, I'll check back in a week.

Thanks for your helps so far. I'll let you know what I find.

 

[coderbond]

I got the three point working, the valves need tuned. Who'd uh thunk.....

So here's what I gather from the book. The Hydraulic pump is actually two pumps in one, at least that's how the diagram seems to read, two set of gears etc. They're divided into two systems, the Hydraulic side and the Transmission side.

The Hydraulic side runs the Three Point and Loader.

The Transmission side runs Steering and the GST Transmission.

The Hydraulic side appears to be fine. There's a page in the manual, it gives a kind of flow chart diagram on the transmission. It says, to test the GST System, I pulled the plug and tested the pressure, came back 0.... Yea.

So I went and tested the pressure at the relief valve and it read 390, I turned it up to 420. The sheet said 412 to 427lbs. I went back and tested the GST port and it reads 0.

I went back to the relief valve and pulled the Pressure Reducer, no residue or nasty stuff on it. I assume its clean. Put it back together, tested the GST port again, reads 0

 

[coderbond]

I went back through the system with the tester and it looks like the hydraulic system is working.

I took a picture of the Hydraulic Circuit and diagram'd it out in MS Paint and attached a copy of it. My pressure readings are listed and I drew a blue line the "way i think" the flow is going. There's a green line that shows another way the fluid can flow, I think. But if the fluid flows along the the blue line and green line why would you need (16) Line Filter, it seems like the fluid could flow around it.

So I'm not sure what to do from here. Pull the GST Cover, check the wet clutch and clean the GST Cover and its assemblies? I hate to tear that thing off there if I don't have to.

 

[North Idaho Wolfman]

The line filter part does look odd, I'll have to check on the purpose of those as they must be doing more than filtering as the are not really easy replaceable.
The fact you are getting a zero pressure reading where you would expect to see a # make me wonder too.

 

[coderbond]

Yea, its weird alright. I read another article and it turned out be the keeper for the wet clutch failed, the pack had separated and the pressure was pouring through the clutch assembly.

I just, I don't want to tear the thing apart without an objective.

Thanks for looking Wolfman

 

[coderbond]

The clutch is blown.

 

[North Idaho Wolfman]

Ouch sorry to see you had that happen to you, that's a very rare thing to have happen.
I hope your clutch pack is cheaper than mine!

 

[coderbond]

the whole clutch assembly is 600$. The retainer and spring costs about 120$.

I figure since the tractor needs split I should just throw a whole new assembly in it

 

[North Idaho Wolfman]

Oh yea yours is a whole lot cheaper, Mine runs $1400.

With the amount of steel that it looks like it tossed, clean the guts of the trans really well!

 

[coderbond]

Looks like I'm not so lucky, they discontinued my 600$ clutch. The new clutch is 1000$. Let you know what happens. Thanks for the help so far.