Hey folks, I got a line on an Esco progressive link hydraulic thumb for my early 90’s Cat 227. The thumb has never been installed, but has sat outside in the snow for several years. It will need some cleaning up. I got the guy down to $5500 CAD. From my research these go for $10k+. My hoe doesn’t have any auxiliary plumbing running down the boom, but should have tons of available valves/switches due to the many functions a buncher runs. It looks like the cylinder needs 3/4 - 1” hose. What would you guys estimate for installation costs? I’m guessing it would take a competent mechanic with a service truck and welder the better part of a full day for the install. The thumb is similar to this, minus the quick attach.
No input eh? I was fortunate to get the contact info of a good Cat mechanic. I was able to have a better look at the hydraulic plumbing and located some capped lines near the base of the boom. These lines appear to run back to the husco valves. I believe most hydraulic functions run off electric solenoids. Next step would be to figure out which joystick buttons activate which valve, then hopefully just move the pilot lines to activate the valve to these lines run to.
One other thing to be aware of. You'll require longer new pins on the bottom end of the dipper. Ensure they are the same metal as the original pins. Over the years I've seen quick hitches fitted with the original pins left in the bucket and new pins fitted in the dipper of the wrong metal type. 1000hrs later every thing is flogged out.
The “new” thumb includes both extended length pins. I’m not sure I’m overly worried about metal types on this old clunker. Doubtful she will even see 1000 more hours. I’m not sure how many different kinds of hardened steel there are that would cause compatibility issues with the already worn bushings. Here are some more photos of the capped lines I’ll be trying to work off of on my 227. Hose clamps running up the boom and down the stick should be install fairly simple.
Thumb install on a new machine including the install of the thumb plus the tubing and clamps on the boom in a clean fashion was between 18 and 25 hours for a competent install guy. That included the new handle in the cab, the wiring, installing fittings on the tubing, installing the thumb to the bucket and the set installed on the stick. You might be able to save a bit of time by using the controls already in the machine but likely not because the mechanic will have to figure out what you have and then how to make it work in the new application. Sounds like an interesting project. Good Luck!
Are you planning on doing the work in a heated shop or outside? It doesn't warm up much in your part of the world until spring. Unless you are doing the work yourself which includes welding you might want to wait until it warms up.
I’ll be waiting until spring. The machine is shut down for the winter.
I got the thumb home and into my tiny, messy garage. Blasted the diesel heater on it for a few hours to melt the frozen earth off it. Started getting grease pumped into the pins to help loosen them up as well as penetrating fluid. The progressive linkage is very seized. I’ve managed to remove several pin retainers and have got the two main pins to move. Looking at the data plate, looks like this unit was built specifically for a Cat 225. I’m guessing it would have been the 225 boom and stick/bucket that would have been installed on my 227. For size reference the thumb stands about 5’ tall and the tines are 1.5”. I definitely underestimated the weight of this thing. Now the big question is, do I paint this Cat yellow? Lol
Yeah nah, Detroit green has to be a goa.
Yeah nah, Detroit green has to be a goa.
After a day of working on the thumb I’ve got one pin removed and all others moving. Just need to get some round stock to keep driving the rest of the pins. Happy to know this restoration won’t need torches! Any ideas where I could find installation instructions? I just emailed Weir Esco to ask them. There are some spacers on the progressive linkage which aren’t currently symmetrical. Are there any rules of thumb for placement of the cylinder mount?
Lots of progress. Got it completely torn down and started painting.
She looks good in new Cat yellow. Also got a local shop to drill grease fitting in this piece of the pro link. Can’t complain for an hour of labour.
Spring is coming quick so I got the 227 fired up. The engine seriously impresses me. The 3208 started like it was running yesterday. Rookie mistake though…she’s frozen to the ground real solid. I also neglected to clean out the tracks before everything froze up. Oh well, Gotta wait for some warmer days. I got started on the thumb install. Was able to get the main pin installed within a couple hours. This would certainly be easier on a level workshop floor! Haha Going to get everything in place then figure out the hydraulic hose routing and lengths I need.
More progress. The linkage pin was MUCH easier.
Was able to get hydraulics sorted out. Needed to pull out the jumper wires to do some continuity test to figure out which wire went where. The electrical box is actually pretty simple. Was able to move some wires around to hook the thumb function up to the switch I wanted. Cracked the pipe caps and was getting seepage when activating the buttons. great success. I got the hose routing measured and will be shopping around for rubber hose. Any favourite online sources for hydraulic hose?
That looks really good! Now that you have the thumb painted all up nice is the rest of the machine going to get painted too?
ah probably not. I don’t exactly have a proper facility for that, nor the ambition. I’ll focus on keeping it mechanically functional at this point.
I’m considering making my own thumb rest. The one in this kit (seen in the my photos strapped in place) seems awfully excessive and overbuilt and needs a lot of welding to attach. Also, it is half on-half off of a fish plate that’s been welded on the stick. Would need to add some 1/2 plate for it to sit flush. Lots of other pro link thumbs look to have small tabs that the linkage rests against similar to this pic. I could make one in that position (option B) or make a simpler one lower (option A) Any ideas what would be a better option?
We always used the half circles like your first photo shows. The reason is that when the thumb is pulled back it slams into those stops and wear a matching groove in the linkages. I've seen plenty of machines with the single sitting in the center which hits the eye of the thumb cylinder rod and over time it makes a mess of the rod eye. The setup in your second photo looks good but uses a lot of steel and welding.
The semi circle rest would press against a beefy piece of linkage, not the cylinder end. It could be made out of 1/2” or 3/4” plate steel. Oh and for clarity, I’d fab 2 pieces, like the first photo. Option A (wedge shaped stop) seems like it would be a little simpler to fab, and much beefier. Could use 1” steel to match what it would press against on the thumb. It would be about 1” tall on the short size and 2” tall on the long side and about 6” in length. With either I’d try to attach some conveyer belt rubber as an added cushion. My only concern with option A would be the cantilever effect it would have on the main pin. The lower the rest is to the fulcrum, the more force that will be cantilevered against the main pin when the thumb is stowed. Not sure if that’s a realistic concern or not.
The stops and saddles are installed to keep the cylinder from hitting the stick when the thumb is in the stowed position. It really doesn't matter which way you go.
I quickly mocked this up with cardboard. I’ll aim to have it made with 1” plate. I’ll be using two pieces…one on either side of the cylinder welded directly to the stick.
For anyone else in a similar position, here is a cost breakdown of some things: Mobile welding quote (cylinder mount only) - $1000 to $1250 CAD Hydraulic lines/fitting/crossover relief valve - $1000 CAD
I got the thumb stops back from the machine shop. Not bad for $50CAD I’d say. I got holes threaded so I can bolt across each stop pieces of conveyer belting rubber as a cushion. Then I can get rid of this monstrosity. Seems awfully excessive. A lot of unnecessary welding.
That looks like it should work perfectly!
Not sure how long the rubber will last, but this should help cushion the thumb at rest. Hydraulic hose order came in. Spent some time installing nylon sleeve with zap straps. I saved about $75 by not having discounthydraulics install it. Just ordered a couple sizes larger to ensure it would slide over the fittings.
The rubber is a nice thought but won't last long depending on the operator. The linkages seem to pick up speed as the thumb is pulled back.
It appears as though the thumb cylinder is hydraulically cushioned. That should help. Got the lines routed and hooked up. I’m not sure if the crossover relief valve will actually add any protection with a double acting cylinder, but I installed one none the less. I cycled the thumb cylinder back and forth a few inches and the circuit seems to operate how it should. The cylinder is drifting out though (opposite of gravity) Not sure if that’s from air in the system, or if the aux valve needs a rebuild.
Could it be that the lines are hooked to a valve that on a buncher might have been set up to constantly apply some pressure to say for example hold the grapple on the cutting head shut so as not to lose grip on a tree? Just a thought, I really don’t know anything about feller bunchers…
I don’t believe so. It should be a standard 6000 series Husco valve with an open center. Additionally, drift happened in the same direction even after crossing the lines. That leads me to believe the same pressure is present in each line, but the large end of the cylinder overpowers the rod side. Or air in the circuit is causing funky things.
Got everything welded up. My brother helped me out with that. He did 3 passes. Unfortunately the drifting issue is more severe than I thought. The thumb falls only a little slower than when activated. It drifts with gravity, so with the stick fully extended, the thumb also won’t stay clamped tight to the bucket. Either the ram seals or a worn valve spool I suppose.
Most thumb cylinders were built extremely cheap. I know of one cylinder builder who did the cylinders for a local thumb and attachment builder. I knew this guy built the cylinders and so I asked him what the deal was. He told me the attachment guy wanted a cylinder for $1,500 and no more. Cylinder guy told him it wouldn't be good. Attachment guy said that is what he wanted so that is what got built. On the cylinder I was handling, he gave me a heck of a deal so I have been recommending him for years. The attachment builder, not so much.
I spent a couple more hours before dark messing with it. Turns out the cylinder appears fine. I swapped the output lines to the other spool on the aux valve. No drifting and the cylinder feels strong. This works well because this spool has port relief valves. I’ll work on setting those later. A small issue appeared with the other lines I attached to the leaky spool. These lines run to a valve used in the swing circuit, and I believe the small amount of flow is causing the swing brake to not activate. Should be an easy solution by just capping the lines and spool ports.
I’m slightly disappointed with the speed of the cylinder. I used 5/8 hose. I was actually recommended to use 1/2”. I think 3/4 would have been better, but oh well. The hydraulic cushioning on this cylinder works very well!
Good day Nice to see the use of the photo's documenting the installation. Kind regards Uffex
I had forgotten that your machine was a logger. There would be an extra valve for a rotation circuit to make the grapple turn either way. It would likely have a motor spool in it. Maybe you could check to see if you hooked into that and not the grapple open and close circuit.
I think you hit the nail in the head, John. The “leaky” spool is for the tilt circuit. I didn’t clue in that could be a hydraulic motor. Would make sense. That circuit also had line locks as indicated in the shop manual, although they were deleted on my machine. The spool I’m now using was for the tip circuit. I had started another thread specifically for the Husco aux valve. HeavyEquipmentForums 14 hours later the cylinder has only drifted about 2”. Should be good enough for my use.