Hydraulic cylinder leak repair, unknown make

[SidecarFlip]

This is what im dealing with, its got some holes on the face of the cap and one of those holes has a small bolt holding a tab. Other cylinders on this rig are the same.

Also if anyone knows what make this backhoe is would be great to fill me in. It has an extendable dipper.

Could very well be the reason why that cylinder is leaking is because the shade tree mechanic who did the cobbly weld job overheated the cylinder and destroyed the piston seal and possiblly the piston itself.

What I would do is take it apart, cut off the cobbled fitting, drill it out and re-tap the hole oversize and install a new threaded fitting. You'll have to make sure there is no burr inside the bore as well.

The whole thing loos pretty crappy in your pictures.

 

[motionclone]

Oh you should see it in person. it does dig though. Got to poking around and cleaned it up a bit and found that those arent actually holes in the face, they are dents from center punch it looks like. Like someone was trying to tighten things up maybe

Anyway, the one hole there is in the cap from the single bolt so I gently tapped the cap counterclockwise and she started to turn so I think it will come apart like that.

Also that plumbing fitting that looks jb welded on doesnt leak so im leaving it alone for now.

 

[SidecarFlip]

I have to ask what you paid for it?

 

[motionclone]

I have to ask what you paid for it?

I paid $1K for it. Guy wanted 1400. I looked for a few months and this was by far cheaper than any other rig out there and thats what I was looking for. Cheap and ugly.

 

[SidecarFlip]

I paid $1K for it. Guy wanted 1400. I looked for a few months and this was by far cheaper than any other rig out there and thats what I was looking for. Cheap and ugly.

Even if you have to invest a grand, you still did just fine. I went looking myself and used 3 point back hoes are stupid priced.

Fix the leaks, give it a pressure wash bath and a 5 gallon finish and you will be golden.

 

[motionclone]

OK, So the cap has no threads only an O-ring and retaining ring to keep it from blowing out. The tab bolted to the cap is so the cap doesnt get sucked into the bore because the cap only has a shoulder for the retaining ring instead of a groove.

I figured all this out over the course of about 2 hours turning clockwise and counterclockwise with no outward movement of the cap. I did notice the cap move outward slightly when i pressurized the cylinder as it moved itself against the retaining ring.

I cut a small groove in the side of the outer tube at retaining ring level like id seen other cylinders have that had a retaining ring. Got it out that way but I think it was supposed to come out the top between the cap and body. Couldnt take pics, too oily

 

[motionclone]

Got it all back together. Looks like the leak was from the shaft seal being damaged. Looks like it may have melted, likely from that fitting that was brazed to the cylinder.

Found some seals and orings from the oringstore.com. They fit perfect and seams to be leak free so far.

Had to drive a straight rod of spring steel into the groove that holds the cap back. I made a retaining ring at first but couldnt get it in after several hours but driving a straight rod into the groove worked slick. Got the steel from McMastercarr

 

[RCW]

You know A LOT more about hydraulic cylinders today than you did a couple weeks ago.

Good for you! Job well done.

 

[motionclone]

You know A LOT more about hydraulic cylinders today than you did a couple weeks ago.

Good for you! Job well done.

This is true, I like fixing my own stuff partly to save money and partly to learn.

Thanks!

 

[D2Cat]

Motionclone, the piece you had to remove to get to the seals originally had a hook bent up at 90 deg just sticking out of the slot. You would normally get a hold of that end tab and pull the keeper out of the slot. In the future you can make that keeper out of keyway stock, often times I see 1/4" and you need to fine 12" pieces. I heat and bend the very end to be able to remove it again.

I didn't see the slot in your first pictures. In the future when the tab is missing you can drive the next smaller size keyway stock in and it will remove the old one. When installing the new keeper, I put a piece of PVC pipe or fitting in the vise and wrap the keyway stock around it to get it to take shape easier.

Who knows how it got butchered up. Just glad you got it figured out.

 

[motionclone]

Motionclone, the piece you had to remove to get to the seals originally had a hook bent up at 90 deg just sticking out of the slot. You would normally get a hold of that end tab and pull the keeper out of the slot. In the future you can make that keeper out of keyway stock, often times I see 1/4" and you need to fine 12" pieces. I heat and bend the very end to be able to remove it again.

I didn't see the slot in your first pictures. In the future when the tab is missing you can drive the next smaller size keyway stock in and it will remove the old one. When installing the new keeper, I put a piece of PVC pipe or fitting in the vise and wrap the keyway stock around it to get it to take shape easier.

Who knows how it got butchered up. Just glad you got it figured out.

I thought it should have come out the top between the cap outside and the bore inside but there wasnt enough room. The diameter of the retaining rod was larger than that gap.

If you see in the pic with the redone cap low in the bore, thats where I could have put the retaining ring in the bore at that point then pulled the cap up or used hydro pressure to seat the cap against the retaining ring. Problem was I didnt have the right tool to put my homemade retaining ring into the bore. I tried a hose clamp as a compressor like i would compress the rings on a piston so it would fit into the bore BUT too much tension for a hose clamp.

 

[D2Cat]

Motionclone, glad you got that thing back together and working. After going back and looking at the pictures it looks like an unusual cylinder and maybe what I said earlier does not apply. Your looks like an adaptation of what I was trying to describe!

Did you have to cut/drill the slot in the side to get the rod in, or was it there already? Normally what ever you put in there, round or rectangular, has a matching groove to hold the cap from coming out or going in. So that clamp would not be required.

 

[motionclone]

Motionclone, glad you got that thing back together and working. After going back and looking at the pictures it looks like an unusual cylinder and maybe what I said earlier does not apply. Your looks like an adaptation of what I was trying to describe!

Did you have to cut/drill the slot in the side to get the rod in, or was it there already? Normally what ever you put in there, round or rectangular, has a matching groove to hold the cap from coming out or going in. So that clamp would not be required.

I cut a groove in the side to get the ring out and thats where I ended up driving the new one back in. Looks like i was supposed to remove the small tab on top of cap, push the cap into the bore, remove the retaining ring then pull the cap out. The cap was unthreaded and only had a shoulder not a groove to contact the retaining ring. Tab was there to keep the cap from going into bore. Yes Odd, havent seen anything like it on youtube or net. I havent seen my backhoe attachment either. I got a telescoping dipper, it comes out about 18",, wierd

 

[Lil Foot]

I think you win for the weirdest cylinders on the planet.
Your backhoe has features reminiscent of an old ARPS (they made some equipment for Kubota, like the B670 hoe, and later became AeroQuip) but I spent a lot of time looking at old hoes (no pun intended) and I cannot identify it. It does not look like a one-off from someone's garage, so I would expect it came from a small, short lived company. Pretty unusual for a small hoe to have an extendable boom. Like you say, weird.

 

[motionclone]

I think you win for the weirdest cylinders on the planet.
Your backhoe has features reminiscent of an old ARPS (they made some equipment for Kubota, like the B670 hoe, and later became AeroQuip) but I spent a lot of time looking at old hoes (no pun intended) and I cannot identify it. It does not look like a one-off from someone's garage, so I would expect it came from a small, short lived company. Pretty unusual for a small hoe to have an extendable boom. Like you say, weird.

Well lucky me!!

I got enough seals and orings to do the rest of the cylinders if it comes down to it. Wish I could find a pic of my exact model so I know what I got.

 

[G.rid]

Looks like i was supposed to remove the small tab on top of cap, push the cap into the bore, remove the retaining ring then pull the cap out. The cap was unthreaded and only had a shoulder not a groove to contact the retaining ring. Tab was there to keep the cap from going into bore.

That's exactly how it's done. At work, I came across two cylinders from a Hiab crane that had me stumped at first. They were the same style but without the keeper tab. The other thing to watch when you rebuild the next ones, is don't push the gland in too far. It will block the oil passage (the one that's welded on yours) then it makes it a bear to get back out. Normally you would be able to pull the rod and piston out to pull the gland with it. But if the passage is blocked, the piston will have to pressurize the air and oil to force the gland out. Probably not too bad on small diameter cylinders like you've got. The Hiabs we're about 5-6" bore.
If all the seals we're good and tight, the gland should stay in place without the keeper. But it's good insurance since it's already there.

Good job on finding parts and getting it back in working order!

 

[Lil Foot]

motionclone-
I ran across a pic of a hoe with one feature pretty similar to yours. Check out the stick mounting plates on the end of the boom. I know nothing else matches, but maybe it's a clue. Pic is a Yanmar YBH 760 hoe.

 

[motionclone]

I ended up doing several things to this backhoe while I had it in the shop in addition to the cylinder seal replacement which is leak free so far.

- I replaced 2 really loose pins.
-Added a boom lock mechanism
-Welded some 8" channel pieces to the bottom of outriggers for bigger footprint -Cleaned up and lubed up the valve block lever mechanisms (not sure of real name)
-Relocated the attachment points to accommodate the additional 3" of the recently added ROPS.
-Built an anti-spin plate for the pto pump so no chain needed.
-Sprayed it down with Kubota Orange rattle cans and a couple Kubota stickers .

looks good from 10 feet away

 

[Lil Foot]

Looks excellent!

 

[SidecarFlip]

Hard to beat a rattle can finish. What 'restorers' of JD tractors do too. Only the JD 'restorers' never bother to pressure wash them, they just paint over the grease and put them on Craigs List.