I joined a couple yrs ago, have not posted but a few times, working on the D4D 78A1 series not sure how to read serial Number cat parts look up tells me no such number exists, number plates all read 78A6160, any way to figure out the yr of manufacture. trying to get some small gaskets and seals ie the seal from oil filter housing to block, it seems to be leaking fairly well there part # is IM6772 which I am certain it has changed with aftermarket replacements. Have not been able to locate. I have been searching the web and have came up with a good share of parts that I am sure need replaced like the bearings and trunnions on the 4S blade that is on it, this machine will not be a everyday use but would like to get things tightened up on it so when it is being used it wont be hurt or wore more. I may be looking for track chains any hints? I do know the chains will not be cheap, but I figured my FIL put all the time into this dozer I can at least bring it closer to the finish line. it will be worked have a few projects for it coming up next summer. thanks in advance for your patience Jerry
This is a D4D built in the mid-60s which is too old for information to exist in the online system. Anything before semewhere around +/-1967 isn't covered. So you will have to rely on paper Parts Manuals, although there are pdf versions out there for anyone who wants something on their computer. The Caterpillar Publication Reference covering 78A machines from first built up to 6379 is UE035100. That will enable you to buy parts, either OEM or aftermarket, by Part Number. A bit of explanation in case you were not aware. 78A1-Up effectively means anything with prefix 78A from first built onwards. If information was available online your machine Serial Number would be written as 78A06160 because all Serial Numbers these days have 8 characters. Decades ago Cat didn't bother with the additional zeros. The 1M6772 Seal that fits between the oil filter head and the block is cancelled and replaced by 8F4994. Specification is 0.907" I/D x 0.207" cross section nitrile O-Ring, 75 Duro.
Thanks Nige, yes I do have a printed copy and PDF on the computer, just came across a oil filter cross reference, which will come in handy when I go through all the boxes of filters here in pole barn
Thanks again Nige, I took the The measurements you gave for the O ring and went through a box my FIL had here of gaskets and orings and found what I needed. Cheers