I took it that he was talking about the nut that holds the body and nozzle down in. I have seen a few of them nuts with a serrated top on them and takes that special tool to remove them.Most the nuts has the hex on them for removal.If the nut is out sometimes the nozzle and body gets stuck in there so it takes a little moving them around to get it to break loose.Sometimes if you tap the side of the body lightly it will loosen them up as I,ve done it many times.I had a good supply of metal caps you used to screw on the bodies and the injector pumps when you took the lines off so dirt etc. wouldn,t get in them so I,d screw one on and tap on it too. New pumps usually had just a plastic cap on them from the factory.

"SJ" wrote:

I took it that he was talking about the nut that holds the body and nozzle down in. I have seen a few of them nuts with a serrated top on them and takes that special tool to remove them..

SJ might be right, he said he tried a 15/16" socket on it. I was thinking he might be trying top put a small socket on the nozzle holder.

That is a pretty high 12A serial #, he might have the D311 with the updated fuel system on it.

I show the 12A series as all D315 engines.
If it has original glow plug pre-coms they had a splined retaining nut to make room for the glow plugs. Have not yet been able to determine size or tool number?

Correction: Looks like the serial number went from 781 to 781x making this an "E" model of 1959 with a D330 engine which changed from the D315 at serial number 5795.

Yes all the 12As used the D315 engine some with starting engines and some direct starting.I have looked in a couple tool books here (not Cat) but that socket isn,t listed in it.Mac Tool Co. used to sell quite a few special tools but don,t know about this one so maybe the demand wasn,t too great so the tool Co. didn,t sell them. I guess Cat would be the only place I,m guessing and don,t have a Cat tool book showing it so possibly is only in the dealer special tools catalog .

I usually screw the fuel line back on once the retaining nut is removed and use a heel bar to prise them up.
AJ

Hey guys..we bought one of those faucet removal wrenches (the kind that takes the nuts off of the bottom of the faucet under your sink) and are going to try that this evening. I think SJ is right when he talks about some of them having the serated edges. We (my father-in-law and I) have looked it over pretty good and it just isn't the 1" nut. I think it takes some kind of special socket. Hopefully this faucet wrench will work, but I've got my doubts because of the torque. Lord knows if it's ever been out, so I figure it's gonna take some work to get loose...especially without the right tool. I appreciate all of your efforts in helping me out with this. If anyone comes up with a tool # or anything, please let me know. You guys are great and thanks much!

Greg.

I even looked in the Cat One Safe Source and they don,t list it in the ones I have but as I said before it,s in the dealer tool book just for the dealer but if you come up with the number you can buy it over the counter.Cat was always shy about selling special tools over the counter but if you have a part number you could buy them.If your dealer is close possibly he would lend you their socket.

I measured the serrated retainer nut on a 7U (with glow plugs) and got 1" diameter as near as I can tell but if you have the D330 engine they used a completely different pre-com chamber and all my various manuals on D330's and D333's show a hex retainer nut.

...well, no luck with the faucet tool. I managed to get it locked onto the serated nut, but the wrench just couldn't handle the torque and broke. I guess it was worth a try though. We're going to try to get a hold of a 29/32" socket to see if maybe it might be tight enough to turn 'em out, since the 15/16" is just a wee bit to small. I''m pretty sure we're going to have to somehow get a hold of that "special" socket from Cat though. Just thought I'd update..

another update....I was just told that for sure they make a socket to fit this type of retaining nut. It's suppose to be the same socket used on the 3208 injection pump hold down nuts. Maybe this can help one of you with obtaining a part #.