Suddenly increasing leak around hydraulic filter

[Westonium]

We've suddenly had an increasing leak around the hydraulic filter underneath the skid plate under the tractor (JD4310). I tried snugging up the filter, and first time there was a tiny bit of give, but today there's not more torque I can give it. So here's the question:

• Is it just the seal giving up? The filter is only 1-2 years old and the tractor gets 1-4 hours a week of use max.
• Is something else clogging causing pressure build-up there?
  • Maybe a permanent screen?
  • If so can I sort that out and re-use the filter? Looks in good shape and no obvious reason it would leak.

Otherwise everything seems fine with the hydraulics. It's an e-hydro model. Drives fine, lifts fine. Leaves a hydraulic snail trail all down our driveway, particularly when under load (uphill)

Advice? Nothing stands out in the manual.

 

[BeezFun]

The filter on most tractors is on the suction side of the system, do you know if that's true on yours? If it is, it's hard to explain why it would be leaking more under load. Are you 100% sure it's the filter that's leaking? Is it possible the filter got whacked by something like a branch? Since the leak started suddenly I'd expect something like that. Can you remove the filter without losing fluid? If so do that and inspect the gasket for tears.

 

[Westonium]

The filter on most tractors is on the suction side of the system, do you know if that's true on yours? If it is, it's hard to explain why it would be leaking more under load. Are you 100% sure it's the filter that's leaking? Is it possible the filter got whacked by something like a branch? Since the leak started suddenly I'd expect something like that. Can you remove the filter without losing fluid? If so do that and inspect the gasket for tears.

Thanks for the reply. There are two replaceable hydraulic filters. One BIG one is on the suction side, and it's out of harms way (mostly) and not leaking. The other one, the one that is leaking, is under a skid plate and is pretty hard to hit.
I did just go for it and removed the filter that seems to be leaking, and nothing looks wrong with the seal. I have another on order which should show up in a couple of days. Bit puzzling. I guess if the new one leaks too that tells me something?

It leaks a little just idling, but it really leaks when using the hydro, like driving.

 

[Roadworthy]

When you replace the filter don't forget to smear a bit of oil on the seal. Inspect the sealing surface on the tractor. After filter contacts the base tighten an additional half to three quarters of a turn. There should be zero leakage.

 

[Westonium]

When you replace the filter don't forget to smear a bit of oil on the seal. Inspect the sealing surface on the tractor. After filter contacts the base tighten an additional half to three quarters of a turn. There should be zero leakage.

I will be sure to keep that in mind. I've replaced the suction side filter, and oil filters on various vehicles for decades and never a leak. Maybe this one is clogged and I can't see it and the pressure is building up? No idea. I do hope this works.

 

[BeezFun]

Do you have a hydraulic diagram? When there are 2 filters typically one is used to filter the transmission circuit and the other is used for everything else. It would help to know where in the circuit that filter is located. So you're saying that you have good enough visibility to be sure the oil is leaking around the gasket on that filter. Since it's a lot smaller than the other filter there's a good chance it's on the high pressure side which would explain the increased leaking under load. The filter should have a bypass valve so that if the pressure gets too high it goes around the filter.

 

[oldnslo]

From your description it sounds like the charge pump filter for the hydrostatic transmission. Typically spin-on filters are not used for very high pressure but I have no idea what pressure this filter should operate at.

since leak started recently agree on something changed but with circuit diagram we are all guessing what changed.

 

[Fallon]

Do you have a hydraulic diagram? When there are 2 filters typically one is used to filter the transmission circuit and the other is used for everything else. It would help to know where in the circuit that filter is located. So you're saying that you have good enough visibility to be sure the oil is leaking around the gasket on that filter. Since it's a lot smaller than the other filter there's a good chance it's on the high pressure side which would explain the increased leaking under load. The filter should have a bypass valve so that if the pressure gets too high it goes around the filter.

He mentioned e hydro, so it a HST. Most every HST I've seen has a dedicated finer filtering filter just for the HST. The other filter is for all other hydraulics (steering, loader, 3pt, etc.)

 

[Westonium]

Interesting - tracking down a hydraulic flow diagram. Hopefully one in this very poorly cared for manual.

 

[BeezFun]

The hydraulic diagram will be in the service manual, not your owner's manual. You can probably figure it out if you go to an online dealer that posts the parts diagrams. By looking at the hydraulic parts diagram you can figure out where in the circuit the filters are.