HOT HOT HYDRAULICS

[TBone]

I have a Kubota M4900 that I bought almost a year ago. I really like the tractor. It does everything I ask and has been trouble free.

There is one thing, however, that worries me. The rear end (around the pto shaft) gets REAL HOT - hot enough that your can't hold your hand on it for more than a second or two. I assume that the heat is coming from hot hydraulic/transmission oil that is being circulated in there. When I noticed it I had been using the pto (rotary cutter) and also had been using the lift quite a bit.

I asked the dealer about it and he said that the oil can run about 100 degrees higher than the ambient temperature, which is close to 100 degrees in the summertime. 200 degrees fahrenheit is pretty hot. I have never noticed any of my others running this hot.

Everything works fine and there are no unusual noises. Do I have a problem? (The tractor does not have hst or a fel)

TBone

 

[kubmech]

Tbone, yes the fluid can get pretty hot. Something simple for you to check, and is a pretty common problem, is to see if the 3ph is coming off of relief when it is in the fully raised position. With the engine a little above idle (say 1400 rpm) and steady, raise the 3ph. You should see an rpm drop off and hear the engine lug slightly (esp. with heavy implement attached). When the hitch raises to its highest position the engine should speed back up and return to the same rpm. If it does'nt, then the feedback linkage on the 3ph needs to be adjusted. It is not centering the 3ph valve to neutral and the hyd's will constantly run on relief when the hitch is in the fully raised position, causing an overheating condition. If you listen good, you should also be able to hear the hissing of the fluid past the relief valve if the linkage is out of adjustment, when the hitch is fully raised.

 

[Thomas]

Art,
Ever think about writing a trouble shooting booklet etc.. for different types of tractors.

I enjoy reading your post!!..and the information in which you have shared,and still your not listed as a Star Member..whats up w/that. /w3tcompact/icons/frown.gif

 

[TBone]

Kubmech,

Thanks - I'll check the 3ph linkage. I hadn't thought of that. I had a Massey one time that would run continuously if you pulled it all the way back.

TBone

 

[Anonymous Poster]

I don't know if this would be related but...when I would lift the loader arm on my case backhoe, it would make a weird noise and sounded like something wasn't right. So, when my boss came out to check it out, he put his hand on the cylinder and it was really hot. This was on a not so warm day, it was hot like what you explained. He told me that the inside is probably all scratched up and a little damaged. o he took it off and replaced it and it's all better now. But I don't really know too much about those machines that you have.


Blake
WA

 

[GarageSmoker]

Is this a "you fix it" thing or a dealer repair? If it's self help, how do we do it? (or, if I have to ask, does that mean dealer fix?)

I noticed the lines around the FEL were pretty warm the other day and all I told my son was to take a break. You have me concerned now that I should be doing something else. Anymore help you can give would be most appreciated.

GS

 

[kubmech]

Thanks Thomas...........

 

[kubmech]

Hey GS, don't panic....... If you had this particular problem you probably would have noticed by now. It would effect your loader operation if the hitch was all the way up and still on relief, the pressure would back up to the loader valve, the loader would operate very erratically. Hyd's get hot when you are working them, sometimes even very hot to the touch. Especially if your unit has an HST. But if you notice that things are running a little hotter than normal then it does'nt hurt to have a look at a few things. If your running the loader pretty hard and hitting relief often then you will build more heat quicker. The 3ph linkage mentioned earlier is called the feed back linkage. Different model tractors are each set up a little different but the idea is basically the same. There is an adjustable link that attaches to one of the hitch upper arms, right or left depending on model, if you have draft control there will be a link on each arm or two off of one arm or off a stryker plate that's part of the top link bracket or........anyway the link from the arm runs back to the 3ph valve and can be adjusted in length. Adjusting the length of the link will determine at what point the valve will go back to neutral during the lift cycle. Generally you want the 3ph to stop raising just prior to the upper lift arms "bottoming out". You should have approx 3/4 to and inch of play in the arms at the top. This <A target="_blank" HREF=http://www.tractorbynet.com/cgi-bin/compact/showflat.pl?Cat=&Board=owning&Number=61369&page=&view=&sb=&o=&vc=1/>Thread</A> has some related info.

 

[GarageSmoker]

Thanks. I have not noticed any operational problems so it was probably just hot from lots of use. The kid is just learning how to use it so he was doing a lot of "do overs".

GS

 

[TBone]

kubmech,

Today was the first time I had a chance to check out the tractor and I didn't have a lot of time then.

As far as I can tell it is coming off of relief like it should. If you hold back on the position control, it doesn't but when you release the lever it moves forward about a 1/4" and it sounds like it is coming off.

I held back on it for a few minutes and could not tell any appreciable difference in the oil temperature. It was pretty chilly today and the oil was very cold from last night.

I might have to wait for warm weather to really test it out but what you suggested makes a lot of sense.

The times that I noticed it being so hot was after running the pto on the rotary cutter. Could something in the pto drive be creating the excessive heat?

TBone