Subject machine went through long period of near-disuse, and much (much) rust formed on my undercarriage components. It's gray-market and all I've ever had to ID parts and assembly is a parts-book, from which I've excerpted the attached page, showing the main components of the track-tensioning system. I'm hoping this looks familiar to some of you from experience with other CAT machines and maybe there's a standard remedy. No normal amount of grease-pressure will move the tensioner on either side. [seems photo-uploading now is only possible from a URL, not from my PC? See https://photos.app.goo.gl/KFyPGRTEKuPY54Sd6 ] The glimmer of hope I found online suggested that the fix might be as simple as inserting a porta-power to assist the grease-pressure cylinder - that is, it might just be a matter of more brute-force. But my inability to identify the other components (to right in the linked illustration) combined with not being able to see or reach almost anything downstream of the grease-cylinder proper make me hesitant, because I could easily be bending something with the porta-power, and make matters worse. If disassembly looked easier or at all pleasant, I'd just do that...though my compressor is also down, so it's not an attractive option. Related questions: Are the track support-rollers "permanently lubricated" or some such? Short of using enough oil to choke an EPA inspector, or absurdly-fussy paint methods, is there any means of keeping my irregularly-used track components from flaking away completely?
Since you say "lots of rust", I have to wonder if the yoke isn't seized in the track frame. I circled where it can be bound up (rusted, preventing sliding). And removal of the adjuster.
Thanks heymccall - good stuff. I just edited this on realizing that it's your own parts-view (shows the spring more clearly) but otherwise is identical, more or less, so the R&R instructions would be about identical, too. Correct me as needed, but I take it the procedure you posted would be intended just to begin the process (remove the hydraulic/grease-pressurized cylinder), but wouldn't get me into the red-circled area you're wondering about - yet still might result in a fix? The two-bolt removal of the adjuster seems relatively painless, and presumably I'd carefully release any residual grease-pressure before doing anything. Maybe you were thinking that getting the adjuster out so that I could directly replace it with my porta-power cylinder (on the same axis) would permit my application of brute-force to break rusty components loose? I'd be game to try as long as you don't think there's a major risk of damage to now-undamaged components, or of personal injury to the extent of causing some disability exceeding, say, 5%...
I put your part number from your Japanese page into avspare . com and came up with it being the same as a 307b. Not sure what you're asking. Adjuster cylinder can be removed if the idler assembly is moved forward 6 inches, like in the instruction. Could your issue actually be that the idler assembly is seized and not the adjuster cylinder?
This is where that adjuster number took me.
OK, I think I get you now. I'd hoped there was just 'bearing contact' between the end of the adjuster (just to right of item 2/adjuster, there's a vertical line that makes them look like they separate there) and the spring/housing assembly, so the adjuster would just fall away if bolts were removed and pressure released, which would maybe allow me to remove the adjuster without getting into days of swearing that breaking open a track would usher in for me. I'm going to go poke at it a bit right now to see what else I can discover.
Some machines (all brands) socket the adjuster into the idler assembly. Others do not.
95% certainty that your adjuster cylinder is seized. It's very common. Your grease gun will make 10000psi so if that won't shift it, a portapower isn't going to make any difference. I've had some success in the past by cutting the end of the cylinder off, pushing the piston out with a press and then re-welding the cylinder. If not, new ones are available, part number 1360246.
A new aftermarket cylinder is only $400.
Thanks to both of you. I was looking at that same image myself, wishing I could rotate it to see the rod end and thus know what I'd be in for when I try to remove it. But when I went out to the machine to reposition and get going, I discovered I am running on fumes (engine stumbling already) so I gotta refuel before anything. I'm still curious as to how such a cylinder would seize, assuming that's it. It's literally packed with grease under pressure, so I wouldn't expect water to get into it. Yes, the 'rod' would be exposed long-term, I'm not trying to retract it, ever, so it doesn't seem like external rust would really be a problem. But then there are those components "to the right" in the assembly drawing...don't they all have some kind of sliding-contact support, other than the spring coils, maybe?
The grease goes to the front of a piston and pushes against the inside of there cylinder. and the seal on the piston. Between the seal and the outside of the cylinder is just a wiper seal which isn't much. Dirt packs into there and rubs agains the inside of the cylinder and the outside diameter of the rod. I've taken the adjusters out of mini excavators and tried to pull them apart with a couple of D6 sized dozers and not moved them at all.
Well, at least it was fun trying... The go-to hydraulic repair shop here offers to replace chromed-steel rods with stainless (for a price...) because rust is such a problem. Maybe that's not unusual in other salty-humid areas...?
You have to get the adjuster out of the track frame at this point. You will be better able to examine and define the issue and then develop a strategy to get it apart.
I don't know the rating of my grease-gun; it's a standard-looking full-size two-hand style...but the hose has a rating of just 4800psi and it hasn't exploded at me, so now I'm wondering if I might actually solve this by getting a 'bigger hammer' so to speak - better lever-style or a cordless. I'd sure prefer that as a solution. Anything to lose other than the cost of the tool?
I pulled out the tensioner-cylinder from one side this morning; happy to report that it was a lot easier than I feared. Wish I'd had official instructions. Mostly it was about realizing that one has to remove the sheet metal L-plate that is bolted on the unit before there's enough clearance to maneuver it out through the inspection-hole. Huge skinned-over ancient grease-blobs (one the size of a baseball) had apparently been squeezed out from one of the 'drain' bolts during some previous fiddlings (I'm guessing some mechanic left them finger-tight before realizing the problem, then tightened them up), but nothing new. So I think it's actually OK, other than that the outermost lip-seal had become embrittled and lost the lip portion while I was cleaning it up. Predictably there was rust-pitting through the chrome, but it was all outside the grease-seals. There was no evidence of grease squeeze-out at the ram end of the cylinder, and after cleaning it up a bit, I 'ghetto-bench-tested' it by shackling a chain around it and then pumping grease into it. I quit when I saw the chain-links starting to bend where they were going around the ram, and getting to that point took way less effort than I'd been putting into pumping both sides while trying to tension the tracks. So I believe my rusty track-links is probably what I'm going to have to deal with. The tracks will move, but they complain about it, even when I've got them elevated off the ground, and in walking the machine around, it's noticeably stiffer than before. So what do people who live in other salty areas (Gulf coast, say) do to treat or prevent this? In fairness, I'd be resistant to moving if all I had for lube was an occasional soaking in muddy water, too...Is there something that's environmentally more friendly than petroleum oil that could be used to free them up, like...oh, I don't know, waste veg oil , lanolin? Or maybe I start with a solid pressure-washing to see if that gets things temporarily moving, then oil it up afterwards? Here's what my typical track-link looks like: https://photos.app.goo.gl/VYNcjq6KDWQq4ZKc8