Personaly as an Owner/Operator of a 312A Model with 5000hrs .... this is the first time i've ever heard of final drive motor issues ...... granted there maybe a batch of bad ones out there, but to outright blast every 312 ever made is BS .....
Cheif ..... with 2660 hrs, there's got to be more to why it's had 2 failures .... maybe it was a back yard repair and the hyd's was not flushed properly, contaminating the second causing a premature failure ..... how many hrs did the original go, was it serviced regularly ect. ..... either way ..... sorry it doesn't sound right .... not with the apparent hrs this unit has and knowing of the same yr machines running around with over 14,000 hrs on them with original drives ...... again sorry it don't wash ..... there has to be a history story on this machine before you got it ....hmmmm ???
Of all the threads ever started here on HEF about 312's, never has there been a mention of these bad finals ...... "EVERY" piece of iron ever made of every brand will have an issue of one sort or another ...... I've owned mine for 14yrs and have had a few stupid things happen (including a complete 360 sommersault) and this tough little hoe refuses to give up. I owned a JD hoe prior to the Cat .... you don't want to get me going on that POS .... was it the machine or was it the Dealer support (probably) or was it a wanna be Hitachi where it was made with a JD engine (POS) in it ...... either way I got a REALLY bad taste in my mouth about ever owning anything JD Yellow ever again .... including JD skids (but that's another story) ........ to each his own ...... I own various brands of everything I have to be in business, so one can not say being brand orientated to everything Cat or Bcat or what ever.
In the issue of the final drive that has caused so much grief .... well ... fix it with a good reman it'll have a warranty do proper preventative maintenance, it'll go another life time for what you are using it for..... sure it costs bucks to fix but that's life owning equipment, all equipment ....Cat like all other manufacturers they out source things like finals, they are not that stupid to keep building 312's with repetative final drive issues made by others.
I am not affraid to keep owning my 312 because of what I have read here ..... or I would not sway someone away from buying one either........
Stumpjumper, you've been around the block once or twice, i'm sure, if you were to find a used hoe i'm pretty sure you would not be fooled by a fancy paint job and would check it out fully or go to a dealer support guy and get in writing any recall issues or what info they'd have to offer ..... maybe even oil samples or how ever your proto call to go and buy iron is.
There are as many threads or more here on HEF posted about Hitachi's or Kohmatsu's, Kobelco's, JD's about main pumps, secondary pumps, pilot controls, finals that pull more on one side than the other, cracked main frames, booms, sticks, hyd cyl's leaking, over heating, ect, ect, ect, ..... all to make us aware and NOT scare someone away from buying it.
Having said that I will check on Monday morning with my product support guy, if there is any bulletins on this issue .... and as anything with "T*ts, Tires, or Tracks" which all cause us problems we'll have to deal with it.................. just my vented .02 cents worth .........Cheers