Hydraulic Blowup

VintageRacer · Aug 3, 2003

On my recently acquired Mitsubishi D2350 I managed to spew hydraulic fluid all over myself and the tractor. I was doing some grading with a blade and got distracted with the 3 point hitch in the "Full Up" position. When the blade reached full up, the engine started to bog down and then a hydraulic line that sits betwen my legs blew, covering me and the tractor with hyudraulic fluid. After several visits, I found a local hydraulic repair shop who made up a replacement line for me.

So now I've got a new hydraulic line in place and I've replenished the transmission/differential with hydraulic fluid. Upon restarting the tractor my son tells me that there is fluid running on the ground near the left front of the engine. Inspection revealed that the hydraulic pump was spewing fluid. Further inspection revelaed that the pump was suffering from a cracked casing. We are in the porcess of getting the hydraulic pump replaced.

So, was their operator error involved or did some sort of relief mechnism fail? I would very much like to avoid another hydraulic oil bath in the future.

Dan

Henro · Aug 3, 2003

Dan,

It sounds like the pressure relief valve on you system failed or is set way too high. Normally the pressure relief valve would open once a high pressure was reached, and the system pressure would not go any higher.

IF the PRV does not work, then system pressure can skyrocket when a cylinder reaches the end of its travel and things will burst, like your hose did. Unfortunately, the pump burst too...Make sure the pressure relief valve is checked for proper operation, or pop goes the second pump might happen...

Might be some other reasons as well. Don't know but I am sure someone else will chime in too... /forums/images/graemlins/smile.gif

Egon · Aug 3, 2003

I'd think it was time for a trip to the shop.

Egon

Slamfire · Aug 3, 2003

Yes ut is operator error, and yes it happens to all of us, some of us all the time. /forums/images/graemlins/crazy.gif

fishstixtwo · Aug 3, 2003

No operator error here, You should be able to raise the 3 pt hitch all the way up. If everything is working properly you should be able to pull the lever to the end of its travel, when the hitch arms reach the top they should automaticly stop. Nothing should ever explode on you. Sounds like you have a pressure relief problem.

rambler · Aug 4, 2003

How does the 3pt hitch work on your tractor? Can you move the lever to any position on a 1/2 moon arc, and the hitch will raise or fall to that position & stay there?

Or, do you push the lever up & the hitch raises, until you let go of the lever & the 3ph stops? The hand lever positions would be up, down, or neutral.

If you have the second type of 3pt control, then your pressure relief valve has failed, & you need to have it serviced.

If you have the first type of 3pt hitch, then your pressure relief valve has failed, and you need to have it serviced. As well, your 3pt hitch selector lever valve is not working right, & you need that looked at as well.

It is possible some other bizzare problem is causing all this, some other valve or pump or hose failure. (Hyds can be a real bear to track down some odd failures sometimes.)

In short, your tractor hyd system needs some serious repair work. Something is very wrong.

--->Paul

Hambone · Aug 4, 2003

Mine works that way also. Put the lever in the up position. Arms raise till bottoms out then the lever moves to neutral.

Magruder · Aug 4, 2003

Sounds like the relief valve didn't work right. I had an Oliver 1855 blow a fill cap off between my feet one time. Soaked me w/ HOT hydraulic. Still got a nasty burn scar on my left leg where my jeans stuck. I'd have it checked.........

stvman · Aug 4, 2003

I'll chime in too and say is is not operator error. I would find a schematic of the hydraulic system, find out where the pressure relief valve is, make shure it is tested replaced or repaired before you put a new pump on. It is definitely not normal you should be able to max out a cylinder without blowing anything.

How long did the tractor run after the hose blew? Just wondering if a weak hose blew pump ran dry seized?

VintageRacer · Aug 6, 2003

In reply to the questions asked:

1. The control for the three point hitch raises or lowers the hitch to the point selected on the control. It does not return to a neutral position when the hitch bottoms out.

2. I shut the tractor down in about five seconds after the hose blew.

My own thinking is tracking along the lines of a failed relief mechanism which follows the thinking of the repair guy who currently is working on the tractor.

Dan