small Chinese Excavator repairs

dfkrug · Mar 21, 2024

P708 said:
I have incorporated some of the MODS offered by TBN members, and added a few of my own. I hope to glean and share information as I go along

You are welcome to add pix and info about modifications to the modifications thread. Link in post #1.

P708 · Mar 21, 2024

drawthree said:
What mods have you done? Any pictures you can share?

First thing I noticed, was on the lower arm. The actuator rod clevis had three brass needle type, flush lube fittings. Each one was damaged by curling the bucket and hitting the ground [done before I got it!]
So, my first mod was to vacate all the flat fittings and go to the ‘zerk’ nipple type.

I then made a cover from scrap pipe and spot welded the cover over the lower part of the rod clevis to protect it from future injury. The original brass flat fittings, I gutted and soldered the ends closed and put them back in place with a little paint to cover them.
I lowered the bucket onto a reddish board and it did its job!

Getting to the battery is a little bit of work. I wired in a 2-prong plug to the battery, exiting near the boom actuator base. It can be used to either charge the battery, or attach a solar charger, just to keep the battery charged during down time.

Got other stuff in the works, but no hurry. Thanks for asking.

dfkrug · Mar 22, 2024

Other than the warranty repairs I did in the first year of ownership of my XN08, this is the first repair I did:

My bucket cylinder rod had a small ding in it, probably from shipping or handling. After 20h of use or so, the drip was more than I could live with. So I swapped out the cylinder in the field with one of my spares, and put the leaky one on the shelf for later.

A few years later, I took it apart and fixed it with a new gland-to-rod seal I bought on eBay, shipped from China. Less than $10 total, BTW.

Some surprising things about this cylinder: The gland unscrewed like most cylinders, but the piston was internally threaded instead of having a nut.

The piston had dual flat spots for gripping. I used a 24" adjustable wrench with a 3-foot cheater pipe, and it eventually surrendered. I had to put a bar through the cross-tube and drive the tractor on top of it. The maker had used thread-locker.

The maker also used a piston-to-rod seal, Glad I did not resort to heat to get that piston off.

Everything looks well-made with rub rings inside gland and on the piston.

I love the Chinese seals that have the metric sizes printed right on them. Easiest seal purchase I have ever had.

BTW, the maker of my mini quoted me $50 total for a full set of seals for all 4 cylinders, shipped via air. I forgot to buy those spares in advance with the XN08, and had no easy way to pay them, so I did not buy.

JamesTheNextDoor · May 26, 2024

One of the brackets connecting the boom and arm has bent. The pin shaft broke and flew off somewhere.

If you compare it with major mini excavators, you can see the difference. They have wedge-shaped reinforcement structures welded between the brackets.

I decided to grind down the elongated part and align the gap between the two brackets.

First, I welded a reinforcement structure to the bracket that had no deformation and then used a bearing puller to straighten the bent bracket.

After aligning, I reversed the bearing puller to prevent excessive shrinkage during welding.

After welding the wedge-shaped reinforcement structure, I also reinforced the outside of the bracket.

Honestly, I didn't expect this part to fail, but fortunately, the bent part straightened out well, and the repair was completed successfully.

I plan to reinforce the kingpost as well, as it is very poorly made and might break soon.

dfkrug · May 26, 2024

JamesTheNextDoor said:
One of the brackets connecting the boom and arm has bent. The pin shaft broke and flew off somewhere.

Are your pins center-bored for grease, and retained by a nut? Or? I assume they are only 25mm, but I can not tell from the photos.

If you put your machine name in your profile, we can all see what you have.