Backhoe 758c hydraulic stabilizer cylinder scratched

[Danica]

Hi, recently while lowering the two stabilizer legs on my 758c (on a 40DA) I scratched the chrome inner cylinder. This in turn did some minor rings to the internal o-rings and now the leak down on one side is pretty annoying.

I saw a guy on YouTube repair a similarly damaged cylinder by slowly filing down the high points in the gouge and eventually filling it with JB Bond (maybe 1-2mm) and buffing it down. That alone was sufficient to mitigate somewhat the leak down but the rings have been damaged I’m sure and replacing them looks like a monstrous job.

Messick’s has the whole stabilizer (one side, used) assembly for just $290. A hydro shop quoted me $500 for a new one. So, doesn’t it seem reasonable to try the DIY (JB Bond) fix and assume if I want perfect functionality I should just buy the (used) unit from Messick’s.

Pics attached.

So has anyone repaired just the cylinder as described and actually have the leaking substantively reduced?

Thanks for any ideas, I got a lot of info on YouTube but the o-rings look like a real PITA.

Thanks TBN!
Danica

 

[oldestgoat]

I couldn't say for sure but I bet a careful buffing of the scratched area to smooth it would at least limit the leaking to when the seals are over that spot, and keep the scratch from damaging the seals.

 

[TO_Bud]

I agree with oldestgoat. The pic doesn't show much if any dripping of oil. If it is just leaving a coating on the cylinder rod I would remove the high spots of the scratch and see how it goes. Do that before moving the stabilizer in and out to prevent any further seal damage.

 

[etpm]

The damage doesn't look anywhere near 1mm deep. Maybe the picture is deceptive. If it was my cylinder I would stone the damaged area smooth. No stones? Start with a new fine file and carefully remove only any high spots. Then sand the area smooth starting with 320 grit wet or dry sandpaper. Move from 320 to 400 and then 600. Back up the sandpaper with the file, this will let the sandpaper act like a stone and give you lots of control, so you only abrade the area you want to. Using a little water, kerosene, diesel, or WD40 as a cutting fluid will keep the sandpaper from loading up as well as helping the sandpaper cut faster. Wet or dry sandpaper can also be made into strips easily by just folding it back and forth a few times and then tearing along the fold. Don't use sandpaper made for wood. A new 6 inch fine bastard cut file and 3 sheets of sandpaper should cost less than 20 bucks.
Eric

 

[Danica]

I couldn't say for sure but I bet a careful buffing of the scratched area to smooth it would at least limit the leaking to when the seals are over that spot, and keep the scratch from damaging the seals.

Thank you I agree and will go that route!

 

[Danica]

The damage doesn't look anywhere near 1mm deep. Maybe the picture is deceptive. If it was my cylinder I would stone the damaged area smooth. No stones? Start with a new fine file and carefully remove only any high spots. Then sand the area smooth starting with 320 grit wet or dry sandpaper. Move from 320 to 400 and then 600. Back up the sandpaper with the file, this will let the sandpaper act like a stone and give you lots of control, so you only abrade the area you want to. Using a little water, kerosene, diesel, or WD40 as a cutting fluid will keep the sandpaper from loading up as well as helping the sandpaper cut faster. Wet or dry sandpaper can also be made into strips easily by just folding it back and forth a few times and then tearing along the fold. Don't use sandpaper made for wood. A new 6 inch fine bastard cut file and 3 sheets of sandpaper should cost less than 20 bucks.
Eric

Thanks for the response, your method is very similar to what is described on YouTube and I will proceed on the first warm day we get up here in the Catskills (which technically is today at 70 degrees). Will print these responses out and know that the addition of wd40 is good. I think I will be able to reduce the leakage by 50%.
Thanks guys!

 

[Danica]

The damage doesn't look anywhere near 1mm deep. Maybe the picture is deceptive. If it was my cylinder I would stone the damaged area smooth. No stones? Start with a new fine file and carefully remove only any high spots. Then sand the area smooth starting with 320 grit wet or dry sandpaper. Move from 320 to 400 and then 600. Back up the sandpaper with the file, this will let the sandpaper act like a stone and give you lots of control, so you only abrade the area you want to. Using a little water, kerosene, diesel, or WD40 as a cutting fluid will keep the sandpaper from loading up as well as helping the sandpaper cut faster. Wet or dry sandpaper can also be made into strips easily by just folding it back and forth a few times and then tearing along the fold. Don't use sandpaper made for wood. A new 6 inch fine bastard cut file and 3 sheets of sandpaper should cost less than 20 bucks.
Eric

PS, “stones”? Like on a grinder but shaped as a block?

 

[etpm]

PS, “stones”? Like on a grinder but shaped as a block?

Yeah, an abrasive block. They come in all sorts of abrasives and grits. I'm a machinist and "stones" of various types are used a lot in machine shops. Most are pretty fine. One very common type are called India Stones. They are widely available. In your case backing up wet or dry sand paper with a file or something else that is hard and flat is a good substitute. The average surface of a new decent quality file is quite flat, the tops of the teeth all fall into a very narrow plane generally less than one third the thickness of a piece of paper, less than 1/40mm. So using the file to back up a piece of good sandpaper makes for a fairly precise "stone". When you are working on smoothing the scratch be sure to use only fine abrasives. Coarse abrasives will add more scratches. Work slowly and carefully and you will end up doing a good job.
Eric
P.S.
Wet or Dry sandpaper is a type of sandpaper and will say so on the back of the sheet. It is meant to be used either dry or wetted with various solvents. Water, alcohol, kerosene, etc. are all suitable solvents.

 

[Danica]

The damage doesn't look anywhere near 1mm deep. Maybe the picture is deceptive. If it was my cylinder I would stone the damaged area smooth. No stones? Start with a new fine file and carefully remove only any high spots. Then sand the area smooth starting with 320 grit wet or dry sandpaper. Move from 320 to 400 and then 600. Back up the sandpaper with the file, this will let the sandpaper act like a stone and give you lots of control, so you only abrade the area you want to. Using a little water, kerosene, diesel, or WD40 as a cutting fluid will keep the sandpaper from loading up as well as helping the sandpaper cut faster. Wet or dry sandpaper can also be made into strips easily by just folding it back and forth a few times and then tearing along the fold. Don't use sandpaper made for wood. A new 6 inch fine bastard cut file and 3 sheets of sandpaper should cost less than 20 bucks.
Eric

You were right, the depth was more like 0.2mm and when stoned down sort of filled itself. Of course the damage has been done to the various internal o-rings but at least it doesn’t further aggravate the situation every time I drop the feet and retract them.

Thanks again!