L39 Hydraulic Shudder When Hot

[gwdixon]

gwdixon I sense your frustration with my limited understanding about the bubbles/foam in my hydro oil. I will have to wait a little while to get enough to change out the oil and filters. At this point I don't know if I'm going with the Amsoil or the SUDT2. If you know the correct Amsoil number I would appreciate it. I'll be using Kubota filters.

avc8130, I have opened my air filter canister and checked both filters (neither appeared to be dirty) and I've washed the screen, radiator and the oil cooler fins.

Thanks!!

Here are two choices for Amsoil:

>Synthetic Tractor Hydraulic/Transmission Oil SAE 5W-30 ATH05-EA

>Synthetic HV Hydraulic Oil ISO 46 HVI05-EA

The hydraulic oil breather is usually a short rubber tube that comes out of the top of the hydraulic reservoir. It is often by the fill hole. Sometimes mud wasps can clog it while other times it just gets filled with debris.

"I will have to wait a little while to get enough to change out the oil and filters." Does this mean enough hours, enough money, or enough frustration? If it were mine the oil and filters would have been changed long ago.

 

[avc8130]

The hydraulic oil breather is usually a short rubber tube that comes out of the top of the hydraulic reservoir. It is often by the fill hole. Sometimes mud wasps can clog it while other times it just gets filled with debris.

That's what I was referring to...

ac

 

[Jim Miller]

OK - I'll check the hydraulic breather hose / tube this afternoon. I just don't recall seeing it. I know where the dipstick is and the FILL cap - just don't recall a breather hose. I'm kinda anxious to find that because of the built-up pressure Saturday afternoon when I pulled the dipstick after running a few hours. If that breather was clear - then that pressure should not have been there...right??

gwdixon - of the two Amsoil choices - which would you choose?? And the having to wait a little while is because of not having enough money right now for the hydro oil and filters. We didn't think we would owe any additional federal income tax - but - unfortunatly that isn't the case. I should be good to go by June. I'm going to pick up my filters in March and then get the oil in May. Bill for oil will hit in June and I'll be OK.

 

[avc8130]

I'm trying to remember. My L45 has a big rubber hose on the fill port in the rear that is definitely a breather. I don't remember my L39 having that. Instead I think the fill cap was a crappy "Bakelite" style. Mine broke the first time I tried to open it. I wonder if they swapped to the newer style at some point.

EDIT: Just checked the fiche. Looks to be the same plastic cover on the L39, not the breather style used on the HST machines.

Built up pressure is NOT a good thing. These are "open" systems. There should be no pressure at the tank.

ac

 

[gwdixon]

If money is tight then the ISO 46 is the better choice. It is about 40% less than the 5W-30. Around $100 for 5 gal. (ISO 46) vs $140 for 5 gal. (5w-30). That is with a discount and does not include shipping. You can see that the Amsoil is comparable, expense-wise, to quality name-brand hydraulic oil.

The 5w-30 stays thicker as the hydraulic oil heats up. If it is not a heat problem, as you have recently diagnosed, then oil more resistant to heat thinning may not be necessary.

avc8130: Just trying to help Jim find the breather tube (as you are). Thanks for your input. I think oil holds more air if it is under pressure so finding and cleaning the breather tube or cap is important in this situation.

 

[avc8130]

Another thing to remember:

For $10 you can become a "preferred customer" with Amsoil for 6 months. They claim it lets you purchase for 25% less than retail. 5 gallons of the 5w30 is $185 retail. The discount makes it ~$140. Clearly becoming "preferred" is worth it if you go this route.

ac

 

[Singalo]

Since you have diagnosed the problem to be heat related (correctly I believe) then the only solution would be to make modifications to lower the heat of the hydraulic fluid.

I am just curious. If the tractor ran fine when it was new, why would the the only solution be to make a modification? I am no hydraulics expert by any stretch of the imagination. But IF this is indeed a heat problem, I would think that another way to attack the problem would be to try and ascertain why and where the heat is coming from, that clearly was not there when the tractor was new. Is the hydraulic cooling system working properly? Is this a factor of the Hydraulic fluid be worn out? I don't pretend to have an answer, Just curious why making non factory intended modifications would be the only solution. When I think of making MOD's, it's typically to address some short coming direct from the factory. Like with every harbor freight Item I have ever owned.

 

[Jim Miller]

I want to respond to a few questions/thoughts that have come up.
gwdixon - thanks for the recommendation on the Amsoil because I don't think heat is the problem. The cylinders, lines and fittings only get warm and not hot.
avc8130-my FILL cap is the BAKELITE and actually is in two pieces. The outer piece that says FILL unscrews off of another BAKELITE screw that has a large slot down the middle that I use a large blade flat-tip screwdriver to take off. I've removed that before to look down into the resevoir to see the fluid/oil and to stick my finger in to see how hot the fluid/oil was. Same warm temp as the dipstick - dumb!
Now, does the fact that my FILL cap is two pieces have anything to do with my problem??
Singalo-I got the L39 used with about 825 hrs. I only had a small John Deere 790 before so I was new to operating a backhoe and up until a few months ago I did not use the tractor for extended hours at a time so I didn't really notice the jerky hydros. And, as I have recently discovered my hydros are not getting HOT as I had first thought. After about 4 hours of operation I can comfortabily touch any part of the hydro system and it is very warm but definately not hot.

While I need to build-up a few bucks to get the Amsoil, I am anxious to see if I have a problem with the breather assembly (whatever that turns out to be) because I definately had pressure in the resevoir Saturday afternoon. My dipstick fits very tight and I really have to tug to get it our. When I removed the dipstick the pressure sounded exactly like the pressure release when you twist off the plastic Coke cap.

I got to find how that breather works for the L39.......

I absolutely appreciate each and every one of you trying to help me!! I love my tractor and I think it's just something simple that's keeping it from running right.

 

[avc8130]

Your experience with the fill is exactly the same as mine. Total crap design. I don't thing it was supposed to be 2 pieces. I think the top just separates from the bottom. My "Screwdriver slot" couldn't handle the torque to get the cap out and I wound up using the dipstick hole as my "fill". Talk about time consuming!

ac

 

[Jim Miller]

Got home from work and here's what I found. The large BAKELITE fill cap has a slot on the outside edge that is definately there for a purpose. The smaller piece that is screwed into the resevoir (that has the large screwdriver slot has a small hole in the center of the screwdriver slot. It appears that the "Breather" design is for any pressure to go from the resevoir through the small hole to the slot on the side of the fill cap. Dumb design - but I can see how it would work and it would be difficult for anything to block the slot AND the hole from the outside.

My FILL cap with the slot on the side was fine. The smaller cap piece that has the screwdriver slot with the hole in the center had "GUNK" plugging up the hole! It appeared that trash or something was plugging that hole. I took a large paper clip and had to really work it around to get the gunk out of the hole. The gunk looked like a drop of clear sealant or gasket material that had gotten stuck in that hole. I can see how that plugged hole would not let anything through. If any pressure was in the resevoir - it was going to stay there - nothing was getting through that hole.

I won't know if clearing the hole will help until this weekend. I'm hopeful this will help!!!!!

Thanks again!!!!!