Importing and modifying a new mini excavator from China

[jodieadair]

Brand-name excavators use a planetary gearbox in their final drives. Each has its own gearbox oil. Our Chinese minis use a simple gerotor hyd motor that uses the same oil that the rest of the hyd system uses. No gearbox.

This is one area where money is saved, and that is why wheel brakes are needed, but I have seen them on only one Chinese maker's mini-X.

Ok, so one less maintenance item.Do you have wheel brakes?

 

[jaylast]

Crap- just typed a long one with pics. Promptly deleted it by accident lol. Will post later! I did post some links prior- my utube has some short vids recapping stuff like the lead weight but I'll also redo this post with some added context and pics.

 

[dfkrug]

.Do you have wheel brakes?

I wish. See my post #303.

I sent my wheel motor pix to the one maker that did install wheel brakes, but they used a different brand. That maker is HeChuang, and the brakes (just 2 RV valves) were installed at the request of a local importer, Jason. He is the guy who sells the Landscape Buddy 1-ton.

BTW, that maker also installed a radiator for the Kubota diesel engine option that includes an integrated hyd oil cooler. Very nice machine.

 

[jaylast]

I guess they act like a check valve when there isn't enough driven hydro pressure to open them. Gravity alone can't open them.

melting and forming your lead into the best shape is a great idea

Almost a necessity sometimes. The sinkers and thin stuff are super easy to get melted compared to a 50lb ingot but it all melts long before steel/tin in open air.
The biggest challenge was finding an appropriate mould without fabbing one. Pics of an old paint tray below that worked good for a wedge shape. Very easily trimmed the result with a circ saw.
Since drilling for me tended to melt the lead and seize the bits I just added the posts when liquid on the last one.



There's about 200lb on center and rear of house floor and 150lb more easily seen in pics centered on the back.
It made a huge improvement dampening the inertia from fast and or fully loaded main boom movement that used to rock or tip the 2200 lb machine.
The HT looks like it has alot less steel at the rear than mine, but also quite a bit more room to play with. Just using the thing and starting to add weight I'm sure you'll get a feel for it. You went too heavy (or main RV pressure too low!) if you can't easily track with the extra weight or the blade can no longer lift machine.


Straightening frame tails. They both consistently had bent a few degrees outward- I'm beginning to wonder if it wasn't from something like hard jump turns due to the consistent force they exert VS the inconsistency of binding the tracks up many times at random in both directions of travel.
Also, during removal and install of the tracks for this repair I had some trouble with binding the tracks again in both directions and to full stop, even at the newest high pressure setting of 2900psi 19.99bar.
There wasn't really any apparent side forces at play when binding/bound.



Either way a 4t chain binder pulled the frame in easily, and I added some 3/8" flat stock gussets top and bottom for now. Could be much more heavily gusseted but it was cold and windy and not close to any power for tools/welder.

When demoing a rather thick and reinforced slab foundation for an old shed I turned up double pump cutoff to 1700psi and main rv to 2900psi. Wow I feel like it's so much more powerful fast and smooth than from stock now with all mods and adustments. Well worth.

 

[dfkrug]

Straightening frame tails. They both consistently had bent a few degrees outward- I'm beginning to wonder if it wasn't from something like hard jump turns due to the consistent force they exert VS the inconsistency of binding the tracks up many times at random in both directions of travel.

Since you were able to bend the wheel motor tails back with just a come-along, my guess would be that you pre-loaded the track tension by getting debris under the sprocket teeth, then drove over something that pushed up on the bottom middle of the track, giving you increased tension. Looks like the moment arm between center line of the sprocket and motor mounting points is at least 2 inches. Gotta be hard on the motor bearings, too.

Looks really good. Keep on strengthening the weak parts.

 

[dfkrug]

There's about 200lb on center and rear of house floor and 150lb more easily seen in pics centered on the back.
It made a huge improvement dampening the inertia from fast and or fully loaded main boom movement that used to rock or tip the 2200 lb machine.

Super important. Your weights prove the assertion that weight (mass) of these tiny minis is what makes them jerky. Good job!

 

[Fredrik]

Excellent.

melting and forming your lead into the best shape is a great idea. And adding steel tubing or studs for mounting is also excellent. I can imagine some curved lead plates that match up perfectly with the inner rear floor of
the house.

When I installed some lead ingots on the rear of my CADDigger, I just drilled holes through the oval-shapes and used bolts and washers. Vibration from use tended to distort the holes I drilled. Steel tubing would avoid that.

Lead is nearly 1.5x as dense as steel, so you would need less material to get, say 200#. Let's see your installation.

I put 350lb of old tire weights in mine. I went to every tire shop around and took all they had. The big barrels they had cant be recycled because weights now are lead or zinc, steel or aluminum. All mixed in the scrap barrel. Pick out the lead and melt with a propane weed burner into dollar store cake pans. cook until done and serve.

 

[dfkrug]

I put 350lb of old tire weights in mine. I went to every tire shop around and took all they had. The big barrels they had cant be recycled because weights now are lead or zinc, steel or aluminum. All mixed in the scrap barrel. Pick out the lead and melt with a propane weed burner into dollar store cake pans. cook until done and serve.

Did you make a mold for the molten lead, or improvise and cut, as JAYLAST did? Very resourceful on the lead scavenging.

 

[jaylast]

That's funny we both used dollar store cake pans and went with about 350# lol.

Little jealous tho cuz I'm assuming they virtually were giving the weights away - mixed scrap would have brought what, less than 10cents at the scrap yard? I spent about 2 bills !!!! Upon melting, no real reason to even scoop out the steel hangers/clips etc. And I also used the weed burning torch (harbor fright)

Thanks dkfrug, yes it could have been the binding coupled with machine weight coming into play.
I think this frame being a little longer and wider must be designed differently enough from most to have a weak area in design there.
The only other occasion I've seen of the frame bending at all was on another 'diggette' like mine. (I think I've just formally named the 'lil lass.)

One thing I will say is the frame was fairly stubborn- my first try was backing (travel motor first) into a tree about a dozen times. The momentum and travel power was expected to at least start flexing the frame back in but I couldn't even notice it move at all.
After that was a 20 ton jack and 40 ton sling strap to that same tree- nothing also, (due mostly to 5" jack travel VS strap stretch).
I skipped a comealong (have used them for mild autobody and frame pulling in past) right to the binder - no cable to stretch and I think it offers much superior reduction to go towards it's 4ton rating - guessing 10 to 1 over a comealong. First time ever using one and was impressed.

weights prove the assertion that weight (mass) of these tiny minis is what makes them jerky

Proof is mostly for math and alcohol imo, but yes it absolutely improved the functionality/usability/comfort for mine. I still did add the adjustable valve to reign in boom function afterwards- it was just still a lil too touchy for me.

BTW Camarata (youtube) just made a vid of his new agt 12- you guys should totally check out the torture test if you havent hahaha; I see repair videos in future for sure lol. Or possible hospital- he almost throws himself right out the cab a couple times!

 

[D'oh]

A Big A+ to WSPoweronline,

Very fast Shipping even to Canada, reasonable pricing, and many available Parts.

Camarata is working his Buddy's Hoe pretty good