Resealing stabilizer cylinder, nick in rod. Fix, ignore, replace?

[joea99]

Kubota BT751 backhoe stabilizer cylinder was leaking. Seals pretty much crumbled during removal. Upon inspection the rod has scratches about mid way, most of which pass the finger nail test. A small cluster about the area of a pea, near a small nick, maybe sesame seed size, can be felt by fingernail. The nick is under 1/4 inch long, maybe pencil lead wide and maybe business card deep.

Can these be reliably repaired? Specialized machine shop? Special epoxy I can then file and sand? (I've seen that done on seawater corroded main propulsion shafts on ships, that operated underwater and they held fine for many years. But those did not have to endure hot oil.

A new shaft is close to $400 buck. Probably take a whole long of cycles over that spot to annoy the seal enough to leak, I'd imagine. Muca ado about nothing?

 

[oldnslo]

Is the chrome on the rod starting to flake or peal around the scratch? If not possibly take some polishing cloth and polish that area smooth. It will eventually eat the seal and wiper if to deep or sharp edges. Will eat the seal much faster if in an area where the cylinder is being loaded but suspect that would be the case if midway on the shaft.

 

[joea99]

Is the chrome on the rod starting to flake or peal around the scratch? If not possibly take some polishing cloth and polish that area smooth. It will eventually eat the seal and wiper if to deep or sharp edges. Will eat the seal much faster if in an area where the cylinder is being loaded but suspect that would be the case if midway on the shaft.

The chrome is not flaking at all, seems quite solid.

The wounds are about mid way so I guess I could attempt to remember not to set the stabilizers in that area and move past it quickly.

I've "polished" it a bit (1200 grit) and the scratches have improved (maybe just hard crud?) and there are no ridges or sharp spots on the edges of the nick. I did find another smaller nick nearby, but neither is very wide and both follow the circumference of the rod.

Not really happy about it, but may as well just soldier on and see how long it holds up.

 

[ROUSTABOUT]

I always run a flat file over bad spots.

 

[joea99]

I always run a flat file over bad spots.

I think first I need to straighten the rod first. Seems .018 inch bend is a bit too much. About 2x Kubota specs.

 

[ROUSTABOUT]

I think first I need to straighten the rod first. Seems .018 inch bend is a bit too much. About 2x Kubota specs.

That's a factory spec to be considered straight. I've put blocks of wood in between barrel and frame to straighten and kept going. .018 is nothing.

 

[BeezFun]

I used a light touch with a fine flat file followed by 1200 grit on a ding on my dump cylinder rod. I got a tiny bit of hot weld spatter on the rod. I had them both covered with welding blankets but of course there was one tiny spot that wasn't covered and Murphy's Law kicked in. I could barely feel it with my finger nail before polishing, couldn't feel anything after. That was 10 years ago and it's still fine.

 

[joea99]

Did put both rods in the press and got them within spec. I can't do much about the nicks except file/polish so there are no sharpies felt. Even if I got new ones, they'd get dinged up before long.

Got them assembled and installed, even re-painted, and so far, no leaks.

Dipper stick cylinder is next. Not leaking but the scraper is shot and it seems to not want to "pull" the way I think it should when digging.

But before that I want to degrease that beast as cleaning using mineral spirits and brake cleaner is messy, stinky and a general PITA. Gonna give Krud Kutter a try as TSC has it in stock.

 

[Alan W.]

Years ago when I worked at a hydraulic repair shop we polished out rod imperfections. The coal mines were rough on equipment. Started with a stone much like a knife sharpening one and worked it flat then polished it out with fine grit paper.
Now if you have a gouge on the inside of the cylinder you can braze the gouged area full. Smooth it down with a die grinder then hone it to an even finish.

 

[joea99]

Years ago when I worked at a hydraulic repair shop we polished out rod imperfections. The coal mines were rough on equipment. Started with a stone much like a knife sharpening one and worked it flat then polished it out with fine grit paper.
Now if you have a gouge on the inside of the cylinder you can braze the gouged area full. Smooth it down with a die grinder then hone it to an even finish.

The die grinding would take a steadier hand than mine.

What about gouges on the rod? Braze them full too? Over a certain size?

 

[Carl_NH]

I had a rock roll into the left stabilizer years ago - used file and 1200 grit to get it smooth, put some JB weld in the small depression (sesame seed size) and sanded smooth again. This worked but the seal was damaged so leaks a little bit - leaves a spot on the floor over a week - should replace the seals but it's not that bad at this point.

I'd say if its not leaking don't mess with it.

 

[joea99]

I had a rock roll into the left stabilizer years ago - used file and 1200 grit to get it smooth, put some JB weld in the small depression (sesame seed size) and sanded smooth again. This worked but the seal was damaged so leaks a little bit - leaves a spot on the floor over a week - should replace the seals but it's not that bad at this point.

I'd say if its not leaking don't mess with it.

I was thinking a bit of JB Weld, but have reservations about how it would hold, over time, under hot oil and heavy usage.

Not so much it would not last, but that it might break free and float about in the hydraulics, eventually to cause mischief in a valve or some such.

Brazing is a bit of a bold step, for me. The heat would likely have bad effects on the chrome plating. But I have seen a number of these ads for the "miracle metal" for low temperature (simple torch) that might work. Stop to think, some forms of silver solder might work too.

FYI, yes, I have been working with hydraulic fluid and solvents this morning.

 

[Alan W.]

I was thinking a bit of JB Weld, but have reservations about how it would hold, over time, under hot oil and heavy usage.

Not so much it would not last, but that it might break free and float about in the hydraulics, eventually to cause mischief in a valve or some such.

Brazing is a bit of a bold step, for me. The heat would likely have bad effects on the chrome plating. But I have seen a number of these ads for the "miracle metal" for low temperature (simple torch) that might work. Stop to think, some forms of silver solder might work too.

FYI, yes, I have been working with hydraulic fluid and solvents this morning.

We never brazed a rod. I think it would mess with the plating.

 

[wdchyd]

TIG weld, get in and get out of the puddle and it won’t hurt the chrome. Fussy file and polish, good to go.
Anything beyond this repair requires a new hyd rod fabricated, easily done with the right equipment.

 

[joea99]

TIG weld with 309SS wire, get in and get out of the puddle and it won’t hurt the chrome. Fussy file and polish, good to go.
Anything beyond this repair requires a new hyd rod fabricated, easily done with the right equipment.

I do have a multi purpose welder, but have not tried the TIG setup yet. Have not done TIG in 40 years.
I'd have to find a shop to do the rod fabrication or get one from Kubota. Several hundred, but imagine a shop would not be much cheaper.

 

[wdchyd]

Easy Peezy

 

[wdchyd]

After polish
Not the same rod as above, but you get the idea

 

[joea99]

Easy Peezy

How do you deal with oil contamination of the nick?

I'd probably want to practice on used a scrap rod, but have no source for them.

 

[5030]

Put in new (flexible) seals and forget about it. Small defects in a hard chrome cylinder rod are like a pimple. The more you pick at a pimple, the worse it gets.

 

[wdchyd]

How do you deal with oil contamination of the nick?

I'd probably want to practice on used a scrap rod, but have no source for them.

No contamination issue, go right over it. I did three more rods this afternoon.
I have lots of scrap rods, too bad you are so far away.