There are special tools to cut the filters open . I'm using a cut off wheel to zip a line just under the lip of the filter . I don't usually check filters but will show you how I take one apart . I normally will take the first changed filters to see what's in them after break in .If you see lots of brass or rubber I would contact the dealer right away . You would by surprised at some of the bits found in the folds . The filter above is from our side widers 3rd change out . Just using it as a demonstration .
The filter just comes out with your fingers .
I'll use a hacksaw to cut the paper filter just to the metal center on both ends.
There was just a few very small flecks of metal .
You can just grab a hold of the paper and pull . It should just come right off .
This is the pressure relief spring at the bottom of the filter casing . If for some reason the filter plugged up the pressure build up will push on the spring causing the fluid to by pass the filter . Chances are that if it got to this point you may have a serious problem . It would at least allow the oil to flow .
I will only use OEM filters on my hydraulic change outs . You could take the chance and use aftermarket but you have to know EVERY spec of the filter you are using to match it exactly . Don't go by the look up # at the aftermarket dealer . That filter may have numerous applications it may not have the right micron filter / in some cases it may not be a reinforced filter or have a pressure release spring etc..... For the price difference now a days is it really worth it ?