John Deere 2355 hydraulic problems

[Windy Hills Farm]

We have a John Deere 2355 loader tractor and the hydraulics work good when you first start it up but as the tractor gets hot after about 1 to 2 hours of use they get slower and slower until you can hardly use them. it has been like this for awhile but last time I used it the power steering started chattering for the first time. When you open the hydraulic fill cap, you can hear a hissing sound and there is lots of hydraulic vapor coming out. I do not know if this is a related problem, but when you try to hover the 3pt hitch between all the way up or all the way down, the loader and the remotes do not work well even when the tractor is first started up.

Does anyone know what is wrong?

 

[Tx Jim]

Welcome to this forum
Yes hydraulic noises & vapor being emitted from hyd filler hole behind seat indicates that rockshaft control valve seals are leaking & need to be replaced. Rockshaft housing must be removed to replace those seals. What type valve controls front end loader(independent or scv)? How many hrs of use since hyd filter was changed & hyd oil suction screen checked/cleaned?

 

[Windy Hills Farm]

Thank for responding. Can you post a diagram with the seals that you said are leaking? The loader is independent. The hyd filter and fluid are replaced every year. It has been probably been less than 100hrs. I just cleaned the suction screen. It had metal shards in it which I am assuming is from the brakes.

 

[rScotty]

There is a thread with a similar problem right now. The final fix hasn't been found, but a suction air leak is my guess. And your problem sounds even more like that kind of problem since the powersteering is involved and the sump is hissing.
Take a look at the hose & connections between the sump where you accessed the hyd screen and up to the intake on the hydraulic pump. Many times an air leak won't leak much oil. It wiill only show up as a oily wetness on the ooutside of a hose and expecially near a hose end. .

Take a look at the thread:

FEL bucket goes spongy after warming up​

FEL bucket goes spongy after warming up

Lifting crooked would point towards potential of one of the lift cylinders leaking internally but that shouldn’t cause any sponginess and would expect that to a constant problem not only when cold.

www.tractorbynet.com

rScotty

 

[Windy Hills Farm]

Thanks rScotty. It could be an air leak. I will check for leaks on the hoses and fittings that I can access easily. I will also probably pull the suction screen back out because with how much shavings were on it, there could been more on the bottom of the reservoir and clogged the screen again.

 

[Harry in Ky]

It's not an air leak. Anything you hear in the filler opening is more likely high pressure oil leaking off somewhere it shouldn't be (as in rockshaft control vale seals as mentioned). What you might try before diving into that. This will be a little easier. Take the rockshaft out of the picture. Look at the plumbing back there and see if you can remove the line leading to the rockshaft and cap/plug that supply. Due to the number of different options, there's no way to know just how your tractor is configured, but if the loader valve is supplied with oil flow ahead of the priority valve you can eliminate everything behind it, still have loader, steering, and transmission circuits. If you have SCV valves you can isolate them as well, but the rockshaft is probably where your issues are, so I would start by taking it out of the loop and see how the hydraulics perform.

Priority valve.

https://partscatalog.deere.com/jdrc/sidebyside/equipment/2642/referrer/navigation/pgId/2662412

 

[rScotty]

Thanks rScotty. It could be an air leak. I will check for leaks on the hoses and fittings that I can access easily. I will also probably pull the suction screen back out because with how much shavings were on it, there could been more on the bottom of the reservoir and clogged the screen again.

The hydraulic pump can suck significant air in through a pinhole leak that won't leak oil to the outside. At most, it just makes an oily coating on the outside of the hose. Some suction lines have rubber hose with worm drive hose clamps. On those, it is best to replace the hose.
But the easiest test for air entrainment is to pull an oil sample with a syringe and look at it. It is very easy to tell by looking. Hydraulic oil with air in it beomes cloudy like that picture shows. If you blow up the photo you will see the cloudiness is thousands of tiny air bubbles. But if you let it stand overnight it will clear up just like new oil.
I posted a picture of what it looks like on that other thread. Here it is again.
rScotty

 

[Tx Jim]

Thank for responding. Can you post a diagram with the seals that you said are leaking? The loader is independent. The hyd filter and fluid are replaced every year. It has been probably been less than 100hrs. I just cleaned the suction screen. It had metal shards in it which I am assuming is from the brakes.

Shown below is a photo rockshaft control valve parts diagram. One must remove rockshaft housing to gain access to these parts.

 

[Tx Jim]

It's not an air leak. Anything you hear in the filler opening is more likely high pressure oil leaking off somewhere it shouldn't be (as in rockshaft control vale seals as mentioned). What you might try before diving into that. This will be a little easier. Take the rockshaft out of the picture. Look at the plumbing back there and see if you can remove the line leading to the rockshaft and cap/plug that supply. Due to the number of different options, there's no way to know just how your tractor is configured, but if the loader valve is supplied with oil flow ahead of the priority valve you can eliminate everything behind it, still have loader, steering, and transmission circuits. If you have SCV valves you can isolate them as well, but the rockshaft is probably where your issues are, so I would start by taking it out of the loop and see how the hydraulics perform.

Priority valve.

https://partscatalog.deere.com/jdrc/sidebyside/equipment/2642/referrer/navigation/pgId/2662412

All JD utility tractor loader control valves I've seen are or should be attached directly behind the pressure control valve. I agree SCV & FEL control valves can easily be isolated from tractor hyd system.

 

[rScotty]

I still think you should at least take a look at the fluid to see if air is being entrained. It meets the symptoms.

But if it is not - and if the hydraulic fluid stays clear when hot - then I agree that the next step is to isolate systems. It's easy to say, " Isolate the rockshaft, Selective Control valves (if it has them), the FEL...maybe even the priority/steering". After all, the big diagnostic advantage to a closed center type of hydraulic system is that you can isolate and close off systems and still have the rest of the hydraulics function.

I simply don't know the particulars of those 55 series JDs well enough to know exactly how to shut off any particular system. But after looking at that valve body picture TX Jim posted, there sure are a lot of places where age in a seal could cause a persistant high pressure leak in a closed hydraulic system. And yes, a leak in that valve body would hiss and make vapor when you open the fill port and listen.... probably even worse than entrained air would.

I'd like to think that with some thought on this someone can come up with specific tests so that Windy Hills can do more diagnosis without so much disassembly. Aren't there some pressure test ports?...
My guess is that a 55 series shop manual - or a special 55 series hydraulics manual - is going to be necessary - along with some pressure gauges.
rScotty