A couple of weeks ago I took the oil filter on 4U1826 apart and inspected it.  I have a bypass filter with the wire mesh outside filter and the cartridge filter inside of it.  My parts book shows the correct cartridge as 4A0332, but the number of the cartridge that is in the tractor is 1R0729.  Cat Parts website shows this as a hydraulic and transmission filter.  Just wanted to be sure this is the correct filter.  

I had the pony turning over the diesel engine today and noticed a large amount of oil coming from the filter.  I shut it down and found the oil was leaking from the filter.  I took it apart and according to my parts book, it shows 2 gaskets between the oil filter cover and base, 5B5937, which is listed as top, and 5B5940, which is listed as bottom.  When I took the cover off, the top gasket was the only one there, and I don't remember seeing a second gasket when I took it apart a couple weeks ago, but that must be the reason for the leak.  The top gasket fits in the groove of the cover, and I assume the bottom gasket sits on the top of the base.  Can anyone confirm this?

Finally, there is a small leak at the top of the cover at the screw (my screw has a T handle vs a hex head).  The parts book shows either a gasket 5B5961 or a washer 8F9207 and seal 8F9206.  My filter has a brass washer.  Could I use either option, and if so, which one is best?

4A0332 cross references to 1R0729.
There should be a gasket 5B5937 on the top of the case 5B5939 in the groove in the cover and there should be a gasket 5B5940 on the bottom of the case in a groove in the base 6B0685. Normally you wouldn't remove the case to change the oil filter so it usually remains undisturbed.
As for the leak at the cover retaining screw, most likely the copper washer has hardened and is no longer able to mold itself to the shape of the sealing surfaces. If you know how to anneal copper then you can repair it or replace it with a new washer. I would stick with the copper washer as the top of the cover is most likely machined to suit the washer and not the seal.

When you reassembled the filter did you make sure everything went to together correctly and did not foul up on assembly? Also you need to put a fair amount of tension on the tee handle to get a good seal. I usually rotate the cover back and forth as I am tightening the handle to help guide everything in.

Regards

Phil

Phil - thanks for confirming part numbers and clarifying the location of the bottom gasket. I didn't remove the case, so the bottom one should be ok. My problem seems to be caused by the components not fitting properly when I reassembled the filters and cover because it wasn't just a leak, but more like a flow. The top gasket was in good shape with part numbers clearly readable, so probably been changed fairly recently by the previous owner. Leak at the copper washer was fairly small. I'll order a new one and make sure everything fits together properly and tighten down appropriately. Appreciate your help.

to anneal copper heat it till it start to change to a blueish colour and quench in water it's easy.