1999 Jd 120

[Tommjr]

I am looking at a 99' JD 120 Excavator.

The machine has 5700 Hrs on it, 10' 2" Stick, 28" Pads, Amulet manual thumb, Excellent condition, 70% Undercarriage, Superclean cab and All New Paint.

Is there any thing I should especially look at?

The machine appears in great condition, 1 owner, runs great.

Any Input would be great.

Thanks!

 

[LowBoy]

Other than a good look at the bottom, and you say it's 70%(?), then that's got plenty of life left in it. Do the pins look worn on the drive side? Need to be turned yet? Chains in good shape? Sprockets? can you rock the pads side to side excessively? If all those things check out good, next would be:
Leaks.
Engine & pump cleanliness.
Service records availability.
Bucket wear/tooth wear, etc.

If it all checks out, then this ought to be a good piece for you. The one owner situation is also appealing.

Watch the Amulet thumb though. It's O.K., but they're a little light in the ruggedness department. We have a new 307 Cat with an Amulet Hydro thumb, and unfortunately when it was installed, no one took the time to check the hydraulic pressure. The first guy to run it was me, and I was thinking, wow, this thing really will grip, I'd better be careful. It is in a rental fleet, so we didn't get a chance to check the relief pressure on it.

The second guy was a rental customer who didn't have the same attitude as I did, went grabbing stuff as hard as he could, and called us to tell us that the thumb ram was bent in a horseshoe. We replace the ram, rewelded the plate onto the stick, and cut the relief pressure from 4400 psi back to around 1400 psi to eliminate any more problems.

The factory steel plate that welds to the stick on these Amulets are way too thin in our opinion. we have a 312C with one also, and it was ripped off the other day, and we had to glue it back on with the electric glue machine...:Banghead

Good luck with your endeavors.

 

[Wulf]

Tommjr, I copied this from another thread that I contributed to, by the way the undercarriage is 30% worn...yes? if so where is that wear, internal, bushing or link height?

Undercarriage is the first thing to look at although the machine price will probably reflect UC wear %. If you can't measure it or don't have the specs checking the sprockets for tip wear is pretty easy, look at the bushings to see what type of wear is present. See if the track is snakey, the shoes are loose/wobbly or the idler is hanging out of the end of the frame to estimate internal pin and bushing wear. Look at the rollers with the track off the ground to see if they turn freely and that the bushings are not worn out.

Hydraulics are probably the most expensive area. Look for neglected leaking cylinders as if oil can leak out then dirt can get in. Listen to the hydraulic pump during operation and with the boom cylinders at full extension. The machine should travel in a straight line when walking. Pick each track of the ground with the stick and bucket and run the track at high speed. Each track should turn at approximately the same speed and listen to the motors.

When lifting the machine up look at the circle bearing (rotek) for wear which shouldn't be more than a couple of millimeters - these are expensive to replace so look closely. When the machine is swinging listen for noise and wear from the swing motor, gearbox, pinion and ring gear (rotek again!)

Listen to the engine and watch for smoke on acceleration and see how much it lugs when working the boom and arm. If it comes close to stall then the hydraulics may be overadjusted or the engine may be weak. Look for leaks and crankcase blowby from the breather

Listen to the final drives when the track is lifted up and rotating and it would be wise to look at the oil for cleanliness and gear wear. If the oil is low then the duo-cone seal may be leaking. If the oil is silvery then the final drive planetaries may be on their way out... some metal is normal though.

Check the boom, stick and boom foot/frame for cracks and welded repairs, look at the movement in the pins, bushes and more importantly the bosses and frame which are expensive to repair.

With the machine hydraulics good and hot put the boom and stick and bucket in the fully extended position and see how much the cylinders drift. Shouldn't be more than a couple of inches in 5 minutes or so.

Good luck!

 

[Tommjr]

I ended up buying this machine.

I had our mechanic on it for over an hour.

Looks and runs great.

I'm putting all new stickers on it, flushing coolant system, hydraulic system. All other fluids and filters are being flushed and changed as well.

I also took the seat out, completely cleaned inside, and added a radio.

I put a new front window seal in it.

Oh yeah, the under carriage was completely replaced at 3700 hours.

I also added a "Rhino" lining to the under belly of the machine.

I will add pics when all is complete.

 

[coopers]

Are you going to keep the manual thumb?

 

[Tommjr]

I haven't decided yet.

Why do you ask?

It's an Amulet Thumb, Are they any good?