Guys ,,, I need some help identifying what year and model this thing is. I bought a John Deere Excavator today and the vin tag under the cab Says 690-A 004687T but on the side of the machine it Says 690B (see picture) right out of the gate I blew a large hydraulic hose at the lower boom mount and all hydraulic functions seem pretty weak, including propel , Im guessing hydraulic pump? Im sure ill have more questions later but for now i need to find out the model and year if possible. The man i bought it from said it was a 690B and a mid 80's. Thanks in advance.
It's a B, the original 690 and A had crane style tracks and the sprocket/drivers were chain driven, lovely. Yours has track chains and planetary drives, MUCH better. Odd looking serial tag though. I'd guess late 70's with that serial number. Does it have mechanical long sticks for controls? By 1982 or 83 they were all joystick controls. They always were slow, not a lot of track power, the operators would get to where any time they wanted to make a turn it was done by putting the bucket down and lifting one track off the ground. Nowhere near as powerful digging as a the Japanese excavators that were starting to show up about then either. But they would do a days work without complaint and the fact that there's still many of them on the market attests to there ruggedness. I seem to recall the track motors were actually two speed, slow and molasses? Seriously. First thing to do is check pressures and make sure all the relief valves are adjusted to spec, no more than 10% above factory, the pumps won't live long if you push them more than that. Those aluminum stack gear pumps do tend to wear and they get bloody hot when they're bypassing too much internally. The track motors are most likely about the same as the pumps, aluminum case Tyrones I think, unless somebody sprang for the Linde upgrade, never seen any but the parts book shows it as an option. The six cylinder engine will run near forever with some love, but the age and the open center hydraulics make the whole machine inefficient as hell, in my experience with several back in the late 80's they were a pig for fuel. If you happen to be friendly with any mechanic or dealer that can put a flowmeter on the pump outlets, they can load the pumps to pressure spec and see what the flow is, if it's below about 85% (means the other 15% is leaking back past the gears) it's time for new pumps. More pictures please! I feel like a trip throught the wayback machine! (My kid has been watching bullwinkle cartoons, part of which is the old Mr. Peabody and Sherman travelling with the Wayback machine)
Thanks for the info lantraxco, yes it seems to be slow, which i can deal with but when i scoop under a load of untouched earth it wont lift it up.. It runs really well, motor is smooth and quiet. its in pretty good shape, i was told it spent its life on a farm... Yesterday i got a hydraulic shower from the burst line.. i'm sure this one wont be cheap. i've looked for something on the internet to decode the vin with no luck. strange the vin says 690A .. Ill get some pics up and thanks for the info.
Your local Deere dealer should be able to tell you the year. Maybe check Ebay for a service manual? Yeah, like I said, start with checking main relief pressures, if the pumps can handle it, then move on to the port relief settings for each function, and finally your boom cylinder piston seals may be toast on the lift side, only takes one leaker to kill the lift.
Funny you should mention that, the left lift boom cylinder is leaking of the front seal and dripping down on the frame.. got some pics to put up.. coming next...
Probably has bad piston packing. When the piston seals don't hold, and you pick up the boom and then hold it there, that cylinder will essentially become a displacement cylinder, that is only the area of the rod is available to hold the load. Pressure will rise to the level of the port relief valve and the boom will twist due to the uneven cylinder force. Does it tend to drift down rapidly when you have a bucket full, or drift rapidly for a bit and then stop?
Brings back memories! Some good, some not so much, I was the mechanic after all, not the operator, lol. Loading one on a tilt deck trailer one day and she decided to come off the low side instead of going on.... oil on the tracks. After that I always made it a point to push the boom down and lift the one end up high, there was always several gallons of hydro oil caught in the center that would only drain out at a good angle. To finish the story, a little dirt sifted onto the trailer and a change of underwear and we were off and rolling.
Looks like the one bossman picked up. Same 30 inch shoes and long levers.. The serial on his is 006288T.
I think it's a 1978 according to a little booklet I got from a used equipment dealer. 1978 starts at 004388 and 1979 starts at 005853.
Looks like your machine was built in 78. As far as the serial number letter thing, JD had a strange system back then and they did stuff like that on all their machines. Your actual serial number is listed in Deere's system shown below. I just don't remember what the "A" in your serial number meant . But you can just ignore it.
My '72 690A actually has the A before the 690 on the S/N plate:
Is there a link to this system or do you have to go through the dealer on it? Trying to look up for my 590d Thanks! Erik
Looking up specific build dates can only be done by the dealer. You can get approximate date ranges from the parts page machine introduction section.