Hey guys hope someone can help, all the hydraulics quit working today on my Mitsubishi mt3201d. Front end loader, 3 point hitch nothing works. recently had a fuel problem, took apart the lines on the injection pump and cleaned. tractor fired right up after that but now complete loss of any hydraulics. Is it possibly the drive gear for the hyd pump? What am I missing? has fluid so thats not the problem. Thanks
all hydraulics quit working mt3201d
- Thread starter Ron T
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Kernopelli
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First thing to do is check the screen in the hydraulic fluid return line and make sure it isn't clogged w/ crud and if it has one, check your hydraulic filter for the same. Either could cause your problem. If they are OK, get a 0-3000psi gauge ($15) and check your hydraulic pressure. Plumb it into any hydraulic hose on the loader and function that circuit. Assuming the loader is plumbed into the hydraulic system correctly, this will tell you for certain if your pump is bad.
I solved my problem by doing what was posted on another reply, I broke the main pressure line loose going to the 4 way FEL controlvalve and bled the air out of the system. Now the hydraulics work fine, still don't know where the air came from. Will now check all the connection fittings for tightness.
Thanks for the replies
Kernopelli
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Glad you got it working again. Air in the system is common but the hydraulic system is vented and self bleeding. If this actually solved the issue, you have another issue with the vent and need to check it out or this will likely be a recurring problem. There should be an inverted tube somewhere on the back of the trans case, probably high above the PTO shaft and this acts as the systems vent and sounds like it is clogged. If there is so much air in the system that it is displacing the fluid to the pump at times, it is a quick way to damage most pumps.
northernguy
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These two issues are unrelated.If your engine is up and running then thats one down,no hyd's could be a few things.Don't condem your pump if you have no pressure on a gauge in line reading 0.There could be a releif valve bypassing.Crack the pressure line from the pump and crank it over with fuel
off see if you get flow from the pump.If you get a good flow your pump is pumping and the main releif is probaly stuck open.My releif got stuck open after cycling a new pincess auto cylinder,a sliver of brass stuck it open,had to pull the top of trans off to get at the valve and clean it out,simple job.
Not sure how your system is plummed,but you should have a main releif valve
before your 3pth and your loader control valve.Are you hearing any pump
wineing sound from your system at high idle,that would be your valve bypassing.Let us know how you make out.
off see if you get flow from the pump.If you get a good flow your pump is pumping and the main releif is probaly stuck open.My releif got stuck open after cycling a new pincess auto cylinder,a sliver of brass stuck it open,had to pull the top of trans off to get at the valve and clean it out,simple job.
Not sure how your system is plummed,but you should have a main releif valve
before your 3pth and your loader control valve.Are you hearing any pump
wineing sound from your system at high idle,that would be your valve bypassing.Let us know how you make out.
northernguy
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About air in the system,the hyd tank or trans case is vented to allow for the expansion of the hot oil.The pump pick up is at the bottom and should not be picking up air unless the oil is very airrated or there is a leak in the suction line and its picking up air as the oil flows by.If the vent is plugged it can cause a negitive pressure in the tank witch can cause the pump to cavitate.
Air in the system after the pump should go away with cycling the cylinders.
Air in the system after the pump should go away with cycling the cylinders.
Kernopelli
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Since he's up and running, all of this is mute I guess but I agree only to a point. Good flow does not equal good pressure though. In some cases, a shot pump could move a normal amount of fluid but not be able to build sufficient pressure. Assuming that everything is plumbed as it should be, the relief valve for the 3 point will only effect the function of the 3 point hitch. It will simply bypass the fluid back to the tank and on to the pump again, allowing the loader to still function. I too have had it stuck open by debris on 2 different Mitsubishi models and the loader still function. Conversely, I installed a New Holland joystick that I was unaware had no internal relief valve and blew a hose on the loader because that is independent of the tractors 3 point relief valve. I ended up plumbing a separate relief into the the loaders system to prevent it from happening again. I suppose that if I was to function the 3 point's control at the same time as the loader's control then the 3 point's relief would relieve the loader as well but otherwise it is locked out of the loader's circuit. Since he had no function to any hydraulics, this is why I suggested putting the gauge in line with the loader to test the pump. It should be the first circuit in the system and it's unlikely that 2 relief valves became stuck open at the same exact time. I agree that the system is vented for fluid release or expansion but it is also to allow the release of air in the system. If what he explained is actually what solved his problem, he has a problem with air venting, not fluid expansion.
Not trying to start a peeing match, just trying to clarify some things. He could have a system that is plumbed strangely...without seeing it I don't know but assuming he has a stock tractor that only has a 3 point relief valve (what I think you are referring to as a main relief valve) and the loader is plumbed normally I think he will have this issue again unless he cleans the tank vent.
