D25U Oil Filter Housing Questions

Guys I have a leaking lower gasket on my oil filter housing that I'm going to replace . Trouble is it seems to be held on with a rather large nut that I have no tool to access because of its location . I bought a 1 1/2" crowfoot wrench I thought might work but won't . I'm not even sure what size it is . A deepwell socket seems to be in order but maybe you fellows can let me know . Whatever it is has to be deep enough to go past the threaded shaft and catch the large nut . If anyone knows the answer please comment . I have included a pic of the nut .

TIA .

I believe the full flow system with the hex nut on top is one size and by pass type a T bar on top is different nut size inside. I want to say 1 7/16 and 1 5/8 inches, but no idea which is which size. I found a friend with 3/4 drive sockets that had been in a fire I cut and chopped on make deep sockets to fit. If I am remembering the pipe in the middle fits thru a 3/4 square socket head to figure out what you have. This was on 9u D6, but I think all the housing are the same ............................ but you know how that goes.

I welded a piece of 1” pipe onto a 3/4” drive socket. Then just used a pipe wrench on the pipe. I forget what size socket it is, but I can check in the morning.

I found out the nut in question is 1 3/8" so I just ordered a combination wrench that size and will heat and bend it 90 degree on the end to access the nut . Thanks to all who commented for their help .

Be sure to clean out the old o-ring real good. Mine may have had a couple crammed in the groove over the years. It was hard as hell and I had to get mean with an angled pick to get it down to bare metal. The new gaskets seated and sealed real nice.

Yeah I figure the gasket has never been changed and is hard as a rock . I'll report back when I get it changed . Thanks

I found a socket and got the nut removed and the canister bottom off . I had to tap the pick tool a bit just to get it under the hardened gasket but did get it off . I honestly think this might have been the original gasket that had never been changed . The filter was a Donaldson P550484 so I ordered one from Amazon . Does anyone know the Cat part # for this filter ?

New filter installed , leak stopped . Now to lube the rollers and start the fence row cleanup .

tube spanner.

also the outer barrel is a separate piece. there is a oring seal under it.

just use the donaldson filter they are the oe supplier to cat. and were even back then. if you look on the air cleaner its made by donaldson.

I had a spindle axle nut deep well socket set and one of the sockets was perfect fit to grab the top of the nut . Saves the work and aggravation of building a tube spanner . Amazon flubbed the Donaldson filter order so just put a Fram on it .

you dont make a tube spanner you buy em pre made. they are a real thing,

hub nut spanners are a style of tube spanners