cat d 7

Trying to figure out the year of my dozer it was said to be 1948 hydrolic blade i been replacing pump of the front ac pump cracked how do i figure out year and model?

Lower rear left above final drive housing, should be a tag, it would appear to be a 3T series if actually a 1948 model, serial number would be 3T, then the number, whatever the count was in the factory at that time

See photo below for tag locations, the other place would be left side of the engine, rear. Both tags should match if the engine is original, and the serial number should be stamped under where the tag was if the tag(s) are missing.

Here is a photo from a military technical manual:

Post the serial number and some one can tell you the year. Serial No is on left side of engine and left rear transmission case. Should start with 3T if it is a '48 model.

I am heading out to check it out it looks alot like the pic

the front tag is cover by a gaurd i can see its tagged d7 and i can feel more letters behind the plate cant see it . winch says d7n hyster engine says 5 3/4 bore block number says 1f8777 this dozer has been so rebuilt with a welding rod i think they could have plated over the number in back they even built up the tracks i will try to take a pic of it tonight it runs great even the poney motor just hydrolic pump is my set back

So it has a 7N Hyster on the back, that may obstruct your view of the tag, maybe a telescopic mirror well help that. Look up by the starting engine (pony), behind it as shown in the photo should be a tag that you can see, clean carefully, nothing abrasive, if not there, scale off some paint in that area, should be stamped under it.

As to the pump, a 1948 model is around the first year(s) a hydraulic dozer kit was offered by caterpillar, previously, dozer kits were after market, built by LeTourneau, LaPlante-Choate, and others.

If it has a Caterpillar dozer kit, there should be a serial number tag, on the blade, 7S = straight blade, 7A= angle blade. There may be or should be a parts catalog or serviceman's reference book for the dozer kit, its a separate book aside from the 3 main books for these which are; Operators Instructions, Serviceman's Reference Book and Parts Catalog.

I am not familiar with early hydraulics on these, might be rebuildable, sourced from a salvage yard or something a hydraulic shop may be able to help rebuild, replace with an as equal, or it could be specific and you need to find one to replace it.

It has a cat strait blade it had a alic chalmer pump self contain reservoir that the pump got cracked we tryed every way to fix it so i went to a junk yard picked up a international td9 pump and mounted it just wish i could put the correct on in i found this dozer just in maine the old timer sold it to me as long as i wouldnt scrapit 5 hrs later me and my dad drove it out of the woods the old boy run it out fuel thank god for my dad i am 41 hes in his 70s i want him to play with this way out back

They are a handy machine on a farm, a little big for some, D6 is probably the best all around farm dozer, little smaller, open station or non R.O.P.S. be darned careful in the woods or around any trees, vibration alone can knock things down.

Some things to know about these that are very important

1.) Make sure the starting engine oil does not get contaminated with gasoline, if that oil thins out from gas, that little 2 cylinder will fail, its splash lube system with 2 deep sumps, keep the oil changed, shut off the fuel to the starting engine once the diesel fires up, I even put a petcock on the bowl of the carb in the drain plug to drain the bowl each time, so there is no chance of less than noticeable amounts of gas leaking down in. Not sure on the Zenith carburetor what causes a leak down if the sediment bowl valve is left on, can happen, overflowed the crank case on one of mine many years back, never forgot that, and check the oil and its condition often. The drain plug on these starting engines are a pain to get to, you can carefully siphon it out if you take the inspection cover off above the crank case, DO NOT allow any contaminants in, dirt, dust, and or lint from rags or papertowels, hose the track off and nearby areas, or make up a long reaching tool to get to the plug, one of mine has some odd ball thing under there so I have to take the side inspection cover off for now. Being a splash lube sump, they called for non detergent oil to settle contaminants out into the sump, not sure if that can be sourced, but modern oil will work fine, just keep it changed out when needed, these little 2 cylinders will run a long time with basic maintenance, they like lots of fuel and spark.

2.) Starting engine will overheat if run long without the diesel engine spinning, it needs coolant to be circulated through it and that only happens when the diesel is engaged.

3.) Do not overspeed the starting engine, when that diesel fires up, the starting engine pinion should disengage at a certain RPM, if not the spring latches need adjustment, the serviceman's reference book covers this. ALso, when starting, I keep a hand on that throttle linkage to slow it down, you can also choke it to stop it quickly, may not be a problem but something to know if not familiar with these old D7's, very easy to screw up a starting engine if you do not pay attention.

4.) Grease fittings, there are tons of of them on this tractor, one of the most important and perhaps overlooked is the dry type clutch pilot bearing (yours should be a dry type if a 1948 model, they were not standard until the last few years the 3T was built) Use an appropriate grease that will not fling out, don't over apply either, but make sure that pilot bearing is kept lubed, if it dries out and that bearing fails you will be pulling that cluttch, replacing that bearing and those thick black woven drive links that attach it to the main flywheel. The other thing is to remember to leave the clutch engaged if running and stationary for any length of time, less wear on the pilot bearing and I believe the transmission interlock device if working properly will not allow it into gear, a lot of old timers would say the same thing, just saves you wear.

5.) Final drives, it may be a good idea to check the pre-load on the dead axle bearing, you can use a large pry bar to see if the sprockets are loose on the dead axle, you do not want to run them like this, if you do, you will be sourcing specialty tools to pull the sprockets and repair the dead axle,bearings, gears etc., sometimes checking them can prevent a serious problem, not an expert on finals, but know what to look for, you can run a magnet in the housing, into the lube to see if any metal flakes, pieces or what have you are present, indicating a bearing or other failure. Bellows seals on these most likely leak, if you take the tractor into water or mud, what leaks out can also get in, you do not want sediment laden water or mud in those housings, or the above will apply.

These are well built and designed tractors of that era, still lots of them out there too, but like mentioned above, some things to know about them.

You said they did some rebuilding on the tracks, be a good idea to see where you stand on that by measuring the components, check to see if the idler adjuster still has room for adjustment or not, if not and the track chains are loose, beyond tolerance, be darned careful in muck and or taking tight turns, I do know what its like to put a track back on one of these, big and heavy, same if you get one of these stuck.

Not to lecture, maybe you know about these things, but in case you did not.... best of luck with this tractor !!!!

If your dozer is 1948 he is d7-3t with motor d8800 and has dry stering cluch and brake

Thank you for the info i had to replace that bearon and took the clutch out i needed the loader to lift it out and it was amazing to see the greas fittings in there in a moment of graet thought i said to my dad great place for grease fittings he said every ten hours get use to it our try a shovel point learned