hydraulic help please at witts end!

[LOOMER]

i have a 73 1530 jd. I am getting shutter and then quits working all togather. the fel goes first, then the 3pt. then the steering, and finally the trany will stop. it is completly random. will do this cold or warm.

What i've done: fluid flush with new filter and cleaned all screens.
rebuilt hydraulic pump


since i've done this i've clocked about 16hrs with no issues. today ran it for about 8 hours then it crapped out on me again. exact same issues. When the tranny finally stopped today i let it sit for about 10minutes and it was able to make it to the trailer. it seems if i let it sit shortly it will function for a very short time then act up again. i also noticed today air bubbles coming out of the hydraulic fluid dipstick. i don't know if this is normal or not.

It has been in the barn since the fresh fluid water isn't the issue. i am stumped. The hydraulic rebuild was just o-rings and i don't see any obvious issues.

thanks for your help!

 

[Gary Fowler]

That sounds a lot like my Yanmar 4220 hydraulic issue that I am having. I have flushed and changed the oil 3 times now and it still barely operates. The hydraulic screen was stopped completely up with gray greenish slimy material and some black goo. This caused first a jerky FEL movement and 3 ph took 5 minutes to raise. The Power steering was hard to move and finally it would not move. It has a shuttle shift with a hydraulic clutch so when it get no oil, it stops. Anyway, while cleaning the screen, I pulled out about 1/2 cup of grey sludge with my fingers. I am sure there is more in the hydraulic reservoir. I am going to flush it several times with diesel fuel, to try and dissolve the sludge and then flush it out, then flush out the diesel fuel with some AW 32 that I have left over then use JD303 to refill. Then I will install a new paper hydraulic filter and hope it works.I think the greymarket dealer put the wrong oil in to start. If that doesn't fix the problem, the last option is replace the hydraulic pump with a new one.

 

[kennyd]

I think seeing the air bubbles is the answer...If after the machine acts up the fluid is foamy looking, then I would suspect a leak on the SUCTION side of the system. This "foaming" condition causes the pump to cavitate.

 

[LOOMER]

Anyone have ideas on how to trouble shoot air leaks or where to look? I don't understand how it could run all day then crap out and the cause be an air leak. i have a new vented resivor cap and have tried running it without the cap.

 

[woodlandfarms]

Heat maybe? something warms up to the point of letting air in... Will be a real PITA to find if this is the case...

 

[MJPetersen]

It cold be that it sucks air when the screen or filter slightly plug which decreases the flow on the intake side of pump. Check every rubber hose connection specifically if there is a hose-over-tubing-with-a-clamp kind of connection.

Mike

 

[slowzuki]

try ytmag, lot more people familiar with oldies there. Big JD's back then had closed center hydraulics, not sure about the little ones.

 

[LOOMER]

Alright, i have another discovery. I keep blowing out the front input seat on the pump. I took and had the pump rebuilt and the oil cooler pressure tested. Put everything back togather and noticed the seal is blown again and the oil cooler and resevoir tank is empty. I then filled the cooler and tank all ran fine besides the leak. Once the resivoir and cooler emptied out quit working again.

So what would cause the seal to keep blowing and why is the tank and cooler not being filled w/ oil. ahhhhh!

 

[RWolf]

As far as the seal I'd suspect a blockage/restriction on the output side of the pump and the relief is set to high or not working all together. As far as bubbles I agree that you have an air leak on the suction side. Very tiny but air will pull easier than fluid. Replace one or all hoses/fittings from the tank to the pump should cure that.

 

[kenstrac]

Is this a closed system,is the cooler before the front pump do you have a accumulator on this?

BTW have you checked charge pump pressure?

 

[LOOMER]

Well i finally got frustrated enough to drop her off at the doctors. It will probably be expensive but i will end up saving the barn. The more i worked on the more frustrated i got and things where getting thrown. Ill end up spending more money on barn repairs do to flying tools.

I will keep you all posted thanks for your input.

 

[rbento]

This problem reminds me of a fuel problem i had. my kubota kept quiting anytime after running fine for a while. Long story short I found the bar code label from the fuel cap floating around in the fuel. sometimes it would stop up the fuel line inside the tank then float away again. Finally i looked inside the tank with a flashlight and caught a glimps of it stuck to the side of the tank.

Another time I had an air leak in my oil furnace. replaced everything pump and all, except one fitting. finally bought a fuel/air filter called a Tiger. That filter burps the fuel before it goes to the pump.
i know these comments are not hydraulic issues but what the heck, you never know what you might learn from someone and besides it already went to the Doctor.

 

[J_J]

Well i finally got frustrated enough to drop her off at the doctors. It will probably be expensive but i will end up saving the barn. The more i worked on the more frustrated i got and things where getting thrown. Ill end up spending more money on barn repairs do to flying tools.

I will keep you all posted thanks for your input.

You said it empties out the reservoir and cooler, but where did the fluid go, Is it on the ground, or what. A reservoir is usually 2 times the capacity of the pump. If the pump can pump 8 gpms, then the reservoir would be about 16 gal. If you emptied out the reservoir, you would definitely see it somewhere. If you have air bubbles as you have stated, then you are sucking air. If you were to ever empty out the reservoir, then you would really suck air, and when you replenished the fluid, there would be air in the system.If that pump cavitates enough, it will destroy it self.

I would definitly check the input line, and filter. Maybe something got in your hydrauic tank and stopped up the line going out of the tank.

It is just amazing to me that those bubbles bursting could cause that much damage. Even ship propellers will cavitate sometimes, and the result will be that the trailing edge will were down and change the efficiency of the propeller.

 

[john_bud]

It's obvious from here (yeah right!) that your return line to the reservoir is clogged up and no fluid is getting back there.

Now we have to wait to see what the "pro's" have to say.


JJ - My TLB has a 18 gpm pump and a 5 gal reservoir and it's all factory. So you may want to modify your statement slightly.

jb

 

[J_J]

It's obvious from here (yeah right!) that your return line to the reservoir is clogged up and no fluid is getting back there.

Now we have to wait to see what the "pro's" have to say.


JJ - My TLB has a 18 gpm pump and a 5 gal reservoir and it's all factory. So you may want to modify your statement slightly.

jb

jb,

I think one should use whatever it takes to keep the hydraulic fluid below 200 degrees, preferably around 180 on the hottest days and working the tractor or unit hard.


Tank functions
The main reason the reservoir exists is to store fluid. The accepted rule for sizing a tank is: the tank volume should be two to four times the pump flow in gpm. This is only a general rule. Some circuits may require more volume, while less fluid may be adequate for other circuits. A 25-gpm pump would work well with a 50- to 75-gallon reservoir for most circuits. With this general rule, the returned fluid theoretically will have two to three minutes in the tank before it circulates again. As Figure 6-5 shows, a baffle separates the return line from the pump inlet line, forcing the fluid to take the longest possible path through the reservoir before returning to the pump inlet. This arrangement also mixes the fluid well and provides more time to drop contaminates and de-aerate. In addition, the fluid spends more time in contact with the outer walls of the reservoir to dissipate heat.



The other option is to have a super large cooler.

Those are not my figures, but all the data I have read, suggest 2 to 3 times in gal, the capacity of the pump. Here is an example of some data.


Hydraulic Reservoir / Tank Size Calculation- Jythra Engineering Services - CAD CAM Services

 

[kenstrac]

I believe this is a closed hyd system it has 2 pumps a charge pump and a variable displacement pump the reservoir he is speaking of is an accumulator that only hold approx 2 gal it also has a priority valve that from previous experiences is the problem .

 

[J_J]

I believe this is a closed hyd system it has 2 pumps a charge pump and a variable displacement pump the reservoir he is speaking of is an accumulator that only hold approx 2 gal it also has a priority valve that from previous experiences is the problem .

You still have to have a large enough reservoir for all hydraulics functions, not only hydrostatic transmission, but power steering, loader cylinders, etc.

 

[kenstrac]

What I said was the 2 gal was the accumulator not the reservoir the reservoir is in the transmission housing.the accumulator is there to give the VDP a charge when it kicks into pump mode.

BTW the charge pump is located in transmission it has a large suction tube leading from the filter housing that pump is a very rugged pump and has a very thin tube on pick up side the only seal it has is an O-ring the only way to properly check this system is with flow and pressure gauges inserted throughout the system if you do not have charge pressure and volume it will not fill accumulator starving front pump

 

[LOOMER]

Sorry you are correct there is a trany resivor which is the main tank. There is also a resivor that sits on top of the pump wich seems to be supplied by the cooler. Should get doctor results today.

 

[kenstrac]

Did you notice a valve on front pump solenoid or manual and do you have a pump disconnect lever on left side on dash