Komat'su PC60-7 --Just Purchased Used--Some Questions

[Welder Dave]

I don't think acid is the answer. If the idler can't move back I don't think much grease will come out. Maybe you could pound a thin wedge/chisel beside the rod and then be able to get the rod out? If you make a wedge use something like an old leaf spring or grind a chisel thinner. Another possible option might be to heat the rod red hot while there is pressure to push the idler forward. It could soften the rod and the idler might move enough the rod comes out. That rod got stuck in there somehow.

 

[Mark A Weiss]

Thanks for the chisel idea. I may not be able to get the angle I need though with the track limiting my headroom. Realize that if I cut the track, I lose all use of the machine. Which means if I can't fix the piston seizure, I've got a 7 ton boat anchor on my property. I'll try to see if I can get a wood chisel in there, but there's no room to swing a hammer.

 

[Welder Dave]

Steel chisel would be better or go to a welding supply and get a wedge for pipe fitting.

 

[Welder Dave]

Here's the kind of wedge that I think may work. You'd have to be careful not to break it and may need 2 but they come to a knife edge so you shouldn't have to modify them.

Pipefitter.com > Pipe Spacing Tools > Fabricators Spacing Wedge

 

[Mark A Weiss]

That's a good tool to have for a lot of applications. Cheap enough, too.
If they had one with a right angle bend, it might work without me having to cut the track off.
Was watching a video on the fastest methods for dissolving rust. Muriatic acid came out on top, dissolving all the rust in 5 minutes.
Meanwhile, I'm using the machine with the Mystery Oil in the cylinder + grease, in the hope that it will eventually work its way into the sliding surfaces of the adjuster piston. I think if I can move the piston again, that metal rod will roll right out once the idler is adjusted all the way out.

 

[Tags]

It looks like the problem is not that the cylinder is stuck, it’s that the adjuster block is stuck due to the rod wedged in there. Probably the best thing to do would be remove the track so you can get the stuck rod out and see what’s going on in there. Hopefully removing that rod frees everything up, if it doesn’t you’ll need the track off anyway to fix it.

 

[Mark A Weiss]

It looks like the problem is not that the cylinder is stuck, it’s that the adjuster block is stuck due to the rod wedged in there. Probably the best thing to do would be remove the track so you can get the stuck rod out and see what’s going on in there. Hopefully removing that rod frees everything up, if it doesn’t you’ll need the track off anyway to fix it.

Is it likely that the lateral pressure caused by the block being off center because of the metal rod, has cause the piston to become frozen due to lateral pressure in a direction the piston was not designed to move?

I must point out that the yoke does move-even with that rod in there, if I pull on the idler--just that it springs back again due to the spring it's attached to. The piston itself appears to be frozen, but if it is frozen due to lateral sideways pressure from that thin metal rod (and I'm not sure if that rod got in there on Friday when I was mucking out my pond, as a lot of other trash ended up in the track frame, or was there from the former owner), then removing the rod would get it working again.
I'm just not sure when that rod got stuck in there.

I was in the pond again today dredging. I think I'm pretty much done with that project now. I drove the machine back and spent an hour cleaning the undercarriage again. Then I pulled the covers off the final drives and cleaned out the muck that was in there. Hosed it down until the water was clean. Then sprayed WD40 and finally motor oil all over the interior to inhibit corrosion. Put the panels back on. Cleaned up the rest of the machine and greased everything that had been in water.

Pulling that track off will be a last resort thing. I'm going to finish as many projects as possible and then when I'm at a point where not having a functional excavator doesn't cause much of a problem, I'll pull the track. I'm not convinced the rod is the cause of the jammed cylinder. I hope I'm wrong, but I think the odds are low and that I'll be into a serious amount of expense and renting a second excavator just to haul that assembly out and put it onto my truck to take somewhere to be rebuilt. That can happen during winter.

 

[John C.]

No use speculating on any of this any more. You have work to do, so do it. You can worry about when you have to fix it.

 

[mutti_wilson]

I guarantee you that the adjuster is stuck because of that metal rod in there. If you can easily remove that rod is clearly binding up. you have the new track and have paid for it. Cut that thing off and move on.

 

[mutti_wilson]

Can you get a cutting torch in there? 10 seconds with a torch would do it.

 

[Welder Dave]

He said the rod is stainless so a torch may not be the answer. If it was mine I'd try to get the rod out before it caused a bigger problem. He can now move the machine to a good position to work on it. Would hate to have the machine stuck in the mud because the track came off or something.

 

[Mark A Weiss]

Can you get a cutting torch in there? 10 seconds with a torch would do it.

I'm not 100% certain that rod was there before I went mucking in the pond Friday. Each time I come out of the pond, I find trash debris of all sorts jammed into the space between idler and frame. The rod may have been in there for a long time, or maybe it just got jammed in there on Friday. I don't know. But I'm not willing to gamble with a presently functional enough machine until I get my major projects done this summer.
The reason I wouldn't bet the farm on that rod being the problem is because the yoke does move a little when I pull or push on the idler with tons of force (it's pushing against the recoil spring), but attempting to move the piston itself via grease gun results in no movement at all. I do hope I'm wrong though! I would love it if it turns out that removing that rod restored adjuster function.
For now, I don't feel like cutting a perfectly good track off and possibly finding that even after removing the rod, I still have a stuck piston. That would pretty much be the end of using that machine. Before that happens, I'm going to get some work down. The track hasn't fallen off. And who knows? A few weeks of driving it around may eventually let the penetrating oil do its thing in there.

 

[Welder Dave]

It's all connected together. I think the logical thing to do is get the rod out and see if that is/was the problem before thinking it's something else. Have you even tried to get the rod out or just figured it's too difficult? If you're digging and pulling all the debris into the track frames and idler, you should position the machine differently so this doesn't happen or don't pull material in so close to the machine.

 

[Mark A Weiss]

It's all connected together. I think the logical thing to do is get the rod out and see if that is/was the problem before thinking it's something else. Have you even tried to get the rod out or just figured it's too difficult? If you're digging and pulling all the debris into the track frames and idler, you should position the machine differently so this doesn't happen or don't pull material in so close to the machine.

I drove the machine into the swamp the other day as part of a dredging operation. Once submerged, I have no idea what trash is getting ingested by the tracks.

I agree that getting the rod out first would be the first order of troubleshooting.
I have tried to get in that space with a tool, but the track above it limits my headroom to about 7". Not enough room to swing a hammer on a chisel. The track will have to come off before I can attack that rod.

I'm sure most folks know this already, but when you've submerged the machine in a muddy bog, it's imperative to remove the covers on the final drives and clean the muck out. Hose everything down and spray oil on all of the surfaces afterwards. I did that yesterday. The quantity of muck that was in there was nothing short of amazing.

 

[Welder Dave]

I don't think most would submerge their machines in a swamp. They'd use swamp mats or something similar to keep the machine out of the muck as much as possible.

 

[Mark A Weiss]

I don't think most would submerge their machines in a swamp. They'd use swamp mats or something similar to keep the machine out of the muck as much as possible.

I've watched quite a few Youtube videos by excavator operators, and I could not believe the places they exposed their machines too. I've also seen excavators that sunk in so deep the engine could not be run. I've never seen "swamp mats" before. What do they look like?

 

[Welder Dave]

Here's a couple video's showing swamp mats.

How to use swamp mats - YouTube

Excavator Venturing Out Onto Quicksand - YouTube

 

[Mark A Weiss]

Here's a couple video's showing swamp mats.

How to use swamp mats - YouTube

Excavator Venturing Out Onto Quicksand - YouTube

Oh those look expensive, plus you need a thumb to lift them easily.
I watch a lot of Letsdig18's videos. He's got a lot of interesting stuff going on.

I was doing stuff like this

 

[Swetz]

If you like letsdigit18, you will like dirt perfect too.

https://www.youtube.com/channel/UCvn8y5Gf090ljxf9xbG5K3w

 

[Mark A Weiss]

Subscribed! Thanks!


I drove the excavator around my lot yesterday and today I checked the yoke/frame assembly to get a better idea of how to remove that rod and... it is gone! The rod dislodged itself and came out. The yoke is firmly against the wall of the frame now, no gap. So I thought "great! maybe I can move the adjust now!" So I raised that track off the ground, ran it back and forth, then loosened the big nut, let out some grease and checked to see if the track adjuster moved. Nope. Put a 2x4 in the track and ran it backwards, but again, it did not move. Tightened the nut, pumped some more grease in, but only took an ounce before the gun went into pressure relief. Adjuster did not move.
My conclusion: the adjuster is still stuck and the metal rod was a secondary unrelated problem which cleared itself.