hydraulic fluid coming out vent

   / hydraulic fluid coming out vent #1  

horses2

Bronze Member
Joined
Oct 23, 2009
Messages
58
Location
Westminster, Md
Tractor
Kubota M471D
Hello All,

I have an L3901 HST 4wd with 1 rear remote. it has started to push hydraulic fluid (a LOT!!) out of the vent tube whenever I use the rear remote valve. when there is no load, all seems to be good. there was so much fluid, I initially thought a line or fitting had failed.


I will be calling the dealership on Monday, and was wondering if anyone had seen this situation or might suggest a cause for this. It has just started this today as I don't remember any fluid trails in the past.

thanks,
 
   / hydraulic fluid coming out vent #2  
If its come out foaming, then its getting air and whipping it up or pickup screen is getting clogged

If its clean then check for a return line restriction
 
   / hydraulic fluid coming out vent #3  
I have seen this from an overfill situation in both the front axle and trans case. The first instance when an M series Kubota had the hubs overfilled and that flowed into the center axle and blew out in the vent during a highway run. The second was a smaller Kubota that was one you had to run first and then check the trans level. Guy overfilled by checking cold and overfilling.

You may well have some other issue but these were the things I saw.
 
   / hydraulic fluid coming out vent #4  
So check the fluid level according to the owner's manual.

Like Six, I'm thinking it's over full. If so, the search begins as to why.

Overheating the fluid can cause a system to puke out the vent because the fluid expands. What task are you doing with the remote?
 
   / hydraulic fluid coming out vent #5  
Well i`m confused... how can it overfill itself if the OP didnt say he added fluid... unless i missed that part of the post.
Actually, i think i saw this issue on youtube from someone with a similar problem.
 
   / hydraulic fluid coming out vent #6  
Seal leaking another system into the hydraulic system.
 
   / hydraulic fluid coming out vent #7  
Well i`m confused... how can it overfill itself if the OP didnt say he added fluid... unless i missed that part of the post.
Actually, i think i saw this issue on youtube from someone with a similar problem.

People can get confused about what they're adding. I've owned big Kubotas for 30 years and still mis-read how much oil to add to the front hubs of an M7040. Their language is very confusing and I could see how anyone could mistakenly overfill. Maybe; maybe not.

Same with some of the smaller hydros. No mention is made of the fact to run first and THEN check. When cold, no oil shows on the dipstick because I have one. Run a bit and there it is. One could easily overfill.

I'm not saying this is the solution in this case, and it may not be, only that it is an easy thing to check off the list. Diagnose problems with the easiest answer first and progress up from there. I have known guys that removed fuel tanks for starting issues only to discover they were out of fuel. Happens all the time.
 
   / hydraulic fluid coming out vent #8  
Diagnose problems with the easiest answer first and progress up from there. I have known guys that removed fuel tanks for starting issues only to discover they were out of fuel. Happens all the time.

Good life lesson right there!!!! :)
 
   / hydraulic fluid coming out vent
  • Thread Starter
#10  
The hydraulic filters were changed a while back (normal maintenance interval). I used OEM filters, and the fluid level was checked and was not overfilled, and no fluid was added since. there is a log splitter attached to the rear remotes. I am using a bungee to hold the rear remote valve open. the splitter has its own self canceling valve to control direction. when the splitter is not in action, all seems to be good. when the splitter is in action, either direction, the fluid comes out the overflow in large quantity, with no aeration or discoloration. Splitter works normally during this time, there is just a lot of fluid coming out of the vent hose when the splitter is in action.
strange thing is, I have used the splitter several times with no issues and the hoses have not been disconnected between uses, so the chance of joint contamination should be rather small.
 

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