B2350 (2650) HST suction filter leak - how?!

[DevonOrange]

Hi all,

I know this has been asked a hundred times before but once more for clarity please.

My HST suction filter had a leak - not much but enough to see some spots on the ground. I carried on using the tractor and bought a new filter to change at some time. I put a flail mower on last week and tried lifting it whilst driving and I could hear a hiss and it wouldn't lift the 3PL up all the way. I guess the leak in the HST filter seal was enough to reduce the pressure and stop all the hydraulics working at the same time - fair enough.

I took the old filter off (it was incredibly tight) and did the quick switch with a new filter. Tightened it one full turn with a filter wrench and topped up the UDT to the correct level. Did a test run with a flail mower running off the PTO and lifting up and down and all was fine.

...until it started leaking again the next day. Also, just a few drops but enough.

I'm pretty sure it is the filter again but I wanted to ask:
1) Is there anything else that could be leaking around that area? (I'm pretty sure it was the filter. The oil drops were collecting at the base of the filter)
2) Is the thread that the filter fits on to just a threaded spigot? Is there a seal behind there that the suction filter meets with? I didn't get a chance to check when I did a quick switch.
3) Why would it still be leaking? If the new filter is on the thread, and tightened up, how is oil getting out? Could it have been over-tightened and deformed the seal?
4) Any other ideas? Dirt on the thread? Should I do a full drain of the hydraulics and try again with new filters all round?

Thanks in advance!

 

[i7win7]

If filter was over-tightened, could the old rubber gasket still be stuck on engine?
Happened to me at 50hr oil change.

 

[DevonOrange]

If filter was over-tightened, could the old rubber gasket still be stuck on engine?
Happened to me at 50hr oil change.

Old seal definitely came off but that’s a fair shout. By the looks of it the threaded nipple is a pretty simple affair-screw the filter on and it stops leaking...except when it doesn’t!

 

[nbryan]

All that comes to mind is there's some kind of deformity, gouge, or burr on the block seal surface preventing a seal, or even damaging the gasket. Hard to catch with a quick spin on & off. Draining so you can check properly is a good idea.
And I'm guessing you didn't totally cross-thread and it's sitting at an angle!

 

[DevonOrange]

All that comes to mind is there's some kind of deformity, gouge, or burr on the block seal surface preventing a seal, or even damaging the gasket. Hard to catch with a quick spin on & off. Draining so you can check properly is a good idea.
And I'm guessing you didn't totally cross-thread and it's sitting at an angle!

It's not cross-threaded and seems to sit pretty snug on the plate. I guess a full drain and clean might be in order. Is it worth trying to save the UDT (only 40 hrs old)?

 

[D2Cat]

I've saved the high dollar fluid by knowing the volume of the tractor being worked on, the get a container that holds that much fluid that also fits under the tractor.

I begin by power washing the tractor so no dirt is available to fall into the container. When all the oil has dripped out I cover the container with a piece of cardboard and slide the container from under the tractor. Let the container set for a day, so anything that may have gotten in there is at the bottom. I use a 3# (red) folgers coffee container and bail the oil out and pour into the funnel when filling. The plastic container even has grips you can use! You can leave a bit of oil in the drain pan if it's cleanliness doesn't suit you.

 

[whitetiger]

You stated "took the old filter off (it was incredibly tight) and did the quick switch with a new filter. Tightened it one full turn with a filter wrench "
The proper installation is, thread the new filter on until the gasket just makes contact, tighten filter 3/4 turn.
You should be able to easily tighten by hand. I suspect that you have way overtightened the filter and distorted the gasket.
You can put baby powder around the area of the filter, see where it gets wet to verify the origin of the leak.

 

[DevonOrange]

You stated "took the old filter off (it was incredibly tight) and did the quick switch with a new filter. Tightened it one full turn with a filter wrench "
The proper installation is, thread the new filter on until the gasket just makes contact, tighten filter 3/4 turn.
You should be able to easily tighten by hand. I suspect that you have way overtightened the filter and distorted the gasket.
You can put baby powder around the area of the filter, see where it gets wet to verify the origin of the leak.

I've just seen that on the filter itself now. I made the mistake of watching 1 youtube video of the filter change whereas if I had watched all 17 of them available I would have seen the hand turn rather than a wrench turn.

I've ordered a new service kit to collect tomorrow and will do the drain and proper fit again. Thanks for the suggestions.

 

[DevonOrange]

You can put baby powder around the area of the filter, see where it gets wet to verify the origin of the leak.

I'm interested in how to do this? Put the baby powder on the filter itself and see where there is baby powder on the back plate?

 

[Pau7220]

The leaking oil will leave streaks in the powder so you can trace the leak.

When you're removing the current filter, pay attention if it's wobbling coming off. In this world of made in China crap, I've had more then one case of the filter base plate being threaded out of square, causing the gasket to have uneven contact. When installing the new one check for the same... and when the gasket just touches, make sure it's complete contact. Check the filter base while it's off and make sure the nipple wasn't cross threaded or machined improperly.

 

[nbryan]

It's not cross-threaded and seems to sit pretty snug on the plate. I guess a full drain and clean might be in order. Is it worth trying to save the UDT (only 40 hrs old)?

I'd save it. Over $100 for a new jug. Unless there's evidence of water cloudyness or other contamination. You'll need a top-up jug anyway, though.

 

[whitetiger]

I'm interested in how to do this? Put the baby powder on the filter itself and see where there is baby powder on the back plate?

After running the unit and while the oil is leaking, spray baby powder on the area. The powder makes the oil trail easy to see. This will verify exactly where the fluid is leaking from.

 

[DevonOrange]

Just a comeback to say thanks for the advice. I bled the hydro fluid by just unscrewing the old filter and letting it pour out there until I got the 4 gallons or so out. The housing around the filter block was quite dirty so I cleaned it all up. Put a new filter on and hand tightened it, then gave it another 1/4 turn. Ran the tractor for 30 mins and there was still a drop coming through, so gave the filter another 1/4 turn (1/2 turn in all) and after running 2 hours now there are no leaks. I guess the solution is to make sure it is all spotless and not overtightened.

I'll post a few pics in case anyone else wants to see the pieces for future reference >>>

New filter, nicely lubed around the seal:

Filter housing, pretty dirty outside.

All cleaned up and ready for new filter: