On my Twenty I have the Factory oil filters (2) that are located on the back of the oil pump /engine side cover. they are no longer available from Cat, I could try to clean them up but have considered a retrofit. Am I correct in thinking the oil comes in the 3/8 pipes-goes through the filters then drains back into the pan? If so could I find a spin on cartridge (2) that would fit inside the housing.

I added a oil filter on my gas 40-Just made me feel better to have a good filter in the system

TIA for Ideas-thoughts-comments

hi, i have a 25 with the same set up. My 25 is missing the filters so i dont kno how it works. i asked on here a long time ago and didnt get anywhere. I still havent figured out what to do. i couldnt see where a small spin on would hurt its better than none. Would just have a to figure out an adapter of some sort. I have a brand new engine just haven't put it back together yet. 3c-445 ian

Are your filter setups like this?







This is the filter setup that was on the big Twenty I hauled home for parts, I can't remember for sure now how it was plumbed, but I do believe the oil has to flow through the center tubes and is forced out through the stacks of felt washers and into the reservoir where it drains back to the sump. It is only a bypass filter setup, meaning it doesn't filter 100% of the oil being circulated. That's about all I remember for now, I'll have to find the parts and dig them out to study them to be able to tell you more.

If I can remember when I get home I will look up the # on the filter I used as a replacement and what I did not use it. If I remember this is a full flow filter system with all oil being filtered before going to the engine. The later filters were bypass filters.
Thanks
Ken

I found some picture that I had saved on my computer. I hope that this will help. The filter that I used is a Caterpillar 4A332. This number has also been discontinued but it changes up to a new number that I can not remember. The 4A332 filter is just about the same OD as the felt washers but it is longer than the stack of felt washers so you will either need to find a new spring or cut the old spring off so that it will hold the steel washers tight against the new filter. As Throw the four steel pins away that hold the felt and steel washers together. I hope the pictures help.
Thanks
Ken

Toby & Ken

Thanks for posting the pic, note the spring and ball for the bypass, It looks to me like the oil is pumped in through the center tube to the top and flowes through the filters into the 2 ---3/8 riser pipes that hold the filters.

I did a retro fit my self using off the shelf filters and some home made adapters, note these filters are listed to be used in Cat fork lifts lifts as well as many other apps.