Perhaps something is restricting the return inlet on the tank, and this might cause pressure to build up
You can put a 100 psi gage in a tee on the OUT port of the return filter.
If the needle is pegged, you have a problem in the tank.
If the filter is bulged, you have a blockage.
Is the filter installed correctly.
Should be an arrow showing the correct direction.
Check your filter base if it has a 1/4" pipe plug opening. (If it doesn't, the T suggested by J_J is the best suggestion).
I installed an industrial filter unit on my grape harvester a few years back. It was big enough that it had a port to put a gauge to monitor the filter if it was getting plugged. This pump from the cleaning fans moves at least 35GPM of fluid (large dia hose, over 1") and the filter dumps into a very large oil cooler (bought from
Surplus Center years ago of all places- the fluid capacity is over 50 GPM if I recall) then to the tank. Even with two yeas on the filter, that gauge doesn't even wiggle (yes it works). When the machine gets turned on, the fans are turned on and don't get turned off till they shut off for the shift (6-8 hrs), so this filters the hydraulic fluid all the time. And it too has a bypass spring inside that can be set in case the filter starts to plug. If I recall, the bypass is set at 25 PSI, well below the burst pressure of the filter.
But if your doesn't have a bypass valve, put the T in and see if the tank is getting pressurized. Sounds like a venting issue. As stated, the gasket is the weakest point on a spin on filter.
(I installed a return line filter on my JD w/ an Edwards Equipment rear mount forklift, got mixed up on supply vs pressure line...opps....went through two filters before I realized my error.... And when I put it on the "correct" line, I found out it still blew it out. Reason, my JD w/ it's hydraulic system returns the oil to the OEM filter housing under the tractor. LOL. The transmission pump pumps oil TO the filter on the tractor then it goes to the closed center pump up front. That housing, according to the shop manual has over 100PSI flowing back TO the filter.....opps. I'd need a one way check valve if I wanted to use a return line filter that dumps to the filter housing. But still, the returning oil has to have at least the tranny pump's min pressure to over come the pressure at the check valve. Figured I'd use a sealed canister type filter, but never did- they had a few for sale on
Surplus Center a few years back, missed my chance-...I just crawl under and replace the tractor filter a bit more often. Could have moved the return line to the tranny case, no pressure, but I was afraid of starving the main pump....tranny pump doesn't move much. It's a Deere closed center system...they have their own issues when you add extra equipment. LOL.)
