How to bleed hydraulics

jeffscoggins · Oct 19, 2008

I just bought a YM1500D but the hydraulics on the loader won't respond. I suppose the best place to start is by bleeding the hydraulics. I've ordered a service manual but it's going to take a while to get here. Is it simple enough to describe the process or am I better off waiting for the book?

3RRL · Oct 19, 2008

Generally, most hydraulic systems bleed themselves. Sometimes a small prime is necessary, but usually the pick up will start pumping fluid and all the air is exhausted when it gets to the sump or a relief valve.
Since this a newly acquired tractor, I'd start with the basics first and work your way down.
-Check hydraulic fluid level
-Change out if dirty or milky
-Check the suction strainer or filter or any screens
-Clean or replace them
-Check your hose connections, fittings and quick disconnects for blockage or leaks
-Check if there are any knobs that need to be "turned" to activate your loader
-Check to see if the valve is functioning and/or if the relief valve on it is functioning
-Check to see if the hydraulic pump is pumping and creating pressure
Others may have more things to put on the list, but this is a good start.

kenmac · Oct 19, 2008

I agree with Rob. I've changed my hdy fluid several times & never had to bleed

tinkertoys · Oct 19, 2008

If the three point works then the fel should work. If you havent found the hyd dipstick it should be by the tranny shifter just to the rear. should be checked engine off all hydraulics down. remove dipstick clean then reinsert but don't screw in oil should on full mark if not add JD 303 hyd oil or equivelent. If this all fails follow the lines from loader valve to splitter block and check for shut off valves. One more thing have you cleaned the hyd filter in bottom of the transmission?

jeffscoggins · Oct 20, 2008

Thanks for advice! I will follow the check list. I'm new to the forum and am still figuring it out, so I posted a new thread when I should have just replied to this one.

I pulled out the hydraulic screen and it was in bits and pieces along with a bunch of sludge. It was a mess. Am I in big trouble? Can I simply put in a new screen or do I need a system flush or something?

tinkertoys · Oct 20, 2008

I have never flushed one of these systems. I have a 195 that had sludge in it. I just cleaned the filter changed the oil and used it. I had too later change it again. I would just get a new filter or a good used one. and fill it with new oil and try it if it works then later causes problems I would just change the oil and clean filter again. You might pour a little diesel through it if you want.

jeffscoggins · Nov 9, 2008

Thanks for all the advice on the hydraulics. While I had the oil out I changed out my rear axle seals, which was a job. My filter screen was in small chunks in the bottom of the case. Since my FEL wasn't working before, but the PTO was working, is there anything else I should check before pouring $40 worth of new oil in the case? Like maybe would it be smart to pull the line going to the hydraulic pump just to be sure no pieces of the screen managed to works their way into that line?

Thanks!

Reg · Nov 9, 2008

jeffscoggins said:
Thanks for all the advice on the hydraulics. While I had the oil out I changed out my rear axle seals, which was a job. My filter screen was in small chunks in the bottom of the case. Since my FEL wasn't working before, but the PTO was working, is there anything else I should check before pouring $40 worth of new oil in the case? Like maybe would it be smart to pull the line going to the hydraulic pump just to be sure no pieces of the screen managed to works their way into that line?

Thanks!

The working PTO is not a diagnostic indication for the non working FEL.
A working 3pt lift might be a useful indication that you have SOME hydraulic capability.
IOW, I'm confused (nothing new) by your description.

jeffscoggins · Nov 9, 2008

I thought someone before mentioned that if the PTO was working that might be a good indicator, but now I see that it was the 3 pt he mentioned, not the PTO. Basically, I'm wondering if I should check anything else in my hydraulic system before putting in new oil so I don't have to drain it again if the FEL still isn't working. I'm thinking the low pressure line should probably be checked for junk in the line, but other than that I can't think of anything.

kenmac · Nov 9, 2008

if the 3 pt lift works. & The only problem your having is loader doesn't work . Check the loader valve. There is no need to bleed. I just put my power steering unit back together & didn't bleed anything. Bleeding will take care of itself

jeffscoggins · Nov 10, 2008

Where would the loader valve be on a 1500?

kenmac · Nov 10, 2008

jeffscoggins said:
Where would the loader valve be on a 1500?

The valve that controls the loader

jeffscoggins · Nov 10, 2008

I started to look at the loader valve and quickly realized that I have no clue what to check. Do I just disassemble it and look for blockage? Thanks so much for everyone's help!

jeffscoggins · Nov 10, 2008

I got it working! Thanks for everyone's help!

Dick_Jermyn · Nov 13, 2008

Jeff,

Tell all of us what you found. We would like to know the cause. Thanks,

Dick, and Yanmar friends.

jeffscoggins · Nov 13, 2008

I'm not quite sure what I did. I found some loose fittings on the bucket and tightened them. I pulled out all the sludge in the rear end and replaced the pieces of screen filter with a new one. I also pulled the low pressure line and blew it out just to be sure there was no crud in that, and while doing that I found a hairline crack in it right up by the pump. A little JB Weld on that then I filled her up with fluid, started it up and it worked. So one or more of those things are what got it!

Jeff

frskit · Aug 18, 2013

My O&K Loader lifts the bucket only some times and does not lift after sitting a few days. I tried bleeding the lines but it didn't work. what else can I do?

/pine · Aug 18, 2013

frskit said:
My O&K Loader lifts the bucket only some times and does not lift after sitting a few days. I tried bleeding the lines but it didn't work. what else can I do?

This thread is almost 5 years old FWIW...but just for the record have you checked the hydraulic fluid level?

EddieWalker · Aug 18, 2013

You don't bleed hydraulic lines. The pump pushed the fluid through the lines and when it gets to the tank, the air in the system goes away there. It's not like brake lines on a car, the hydraulic fluid on a tractor moves through the system and into the tank just by operating it.

If you have plenty of fluid in your tank, then you should check to make sure your pump is putting out the proper amount of pressure. Have you replaced your filters? Are they the proper filters?

If that's not it, then you need to rebuild your cylinders. Usually it's one of the seals, but in some cases it could be the piston or the inside of the cylinder could be worn and need to be replaced.

Eddie