1211 slow hydraulics

[olds45512]

The lift on the 1211 seems slow, actually it seems a bit faster at an idle than it does at wot. I checked the pressure and at an idle i have about 50psi when its just running and 650psi when the lift is fully extended, at wot the pressure drops to almost zero just running and 500psi with the lift extended, seems weird that i would have less pressure when the pump is spinning faster. This is the part where Jon says "pressure has nothing to do with speed" which may be true but i'm just trying to relay all the info i have at this point. This tractor does have a jd 2 spool valve installed in it and all the lines are new, any ideas?

[olds45512]

I pulled the lines off the lift cylinder to make sure both had good flow and noticed something in the process, regardless of which way i move the lever i have fluid coming from both lines, one has alot of pressure and the other just runs out and it reverses with the lever. I removed the spool valve and disassembled it but don't see anything out of the ordinary other than it was a bit dirty inside, i have it cleaned and with put new o rings in but i doubt this is my issue.

[cubs-n-bxrs]

Tim the only thing I can offer up is maybe try changing the filter. The 149 I got a couple years ago had the exact same symptoms. Hydraulics ran faster at idle than they did revved up. From the advice from Jon I changed the filter and the hydraulics started acting like normal.

[olds45512]

Originally Posted by cubs-n-bxrs

Tim the only thing I can offer up is maybe try changing the filter. The 149 I got a couple years ago had the exact same symptoms. Hydraulics ran faster at idle than they did revved up. From the advice from Jon I changed the filter and the hydraulics started acting like normal.

The fluid and filter were new in the spring, i doubt that's the issue but i may pick up a new filter on Monday when the Napa opens.

[J-Mech]

I remember Kelly's issue. I agree it's the same symptoms. Tim, I'd change the filter and give it a try. I don't know what oil your running (and I don't care), but remember it is cold outside and some hydraulic oils aren't the same weight as Hy-Tran. Mine get slower when it's cold too. May or may not be the issue. Losing speed and pressure when the engine is running faster indicates that it's losing flow though, which is likely a plugged filter.


Just for explanation purposes:
When you took the lines off and the pressured line puked out is obvious: It's the one under pressure. The reason the non-pressured line puked low pressure oil is because when you move the spool valve it does two things: 1.) Directs pressure from the pump to the cylinder. 2.) Opens the other port up to "tank". Remember though, that the "tank" port is the other line that is on the hydro pump. The left over fluid that isn't used in the charge circuit for the main pump also returns on that circuit. So what you are seeing is just back-fed oil on it's way to tank. It's low pressure, but it flows out an open line easier than back into the pump/tank.

[olds45512]

Good call guys, i got a new filter and its back up to full speed and the pressures on the gauge look much better. Thanks again.

[darkminion_17]

I bet a lot of hydro problems are filter related.

[cubs-n-bxrs]

True story Lew. I picked up that 149 a couple yrs ago for a Benny because the hydraulics barely worked. The guy thought the hydro was toast. Spun a new filter on and was back in action.

[olds45512]

The only reason I was doubting the filter was because I had just replaced it in the spring, after seeing how dirty the inside of the JD spool valve was I'm thinking that's what helped plug the filter. If I have time after work I might cut the filter open and have a look.

[Terry C]

Originally Posted by darkminion_17

I bet a lot of hydro problems are filter related.

That's a dry sense of humor you got there Lew.
I on the other hand think most hydro problems are owner related.