Hey folks, I’m mid way through a hydraulic thumb install on my early 90’s Cat 227 (buncher converted to excavator with 225 boom/stick) The thumb is plumbed through a Husco valve (was used to operate the buncher head functions) and operated via joystick buttons (simple on/off). The Husco spools are controlled by pilot pressure from solenoids. One of the spool appears to have work port relief valves. My questions are: A. Is this in fact a work port relief valve? B. Can a work port relief valve be installed in place of this plug? If so, how would I figure out what is compatible? TIA!
Good day If the line goes out to your extra service the port relief will always screw in to that port. Husco are active on the web mailing with the make up number may well help some more. The second shot looks like a port relief blank just to replave a live port relief. Kind regards Uffex
Thanks for your input. I had planned to reach out to Husco directly. I paid for a PDF repair manual and spent a couple hours looking through it. The one I got doesn’t seem to have an index so it was a rather tedious process. I’ve mostly figured this out. The auxiliary lines that run to the base of the boom are plumbed to the old “tilt” function. It also appears as though the tilt check valve was deleted (which I wouldn’t want on a thumb circuit anyway). Another page confirmed that the plug is actually a flow control valve. Could I swap that out for relief valves? I’m now wondering if I can run the thumb through the old “tip” function, which already has line relief valves (work port reliefs) and remove enough shims to get the pressure relief to a safe level to allow the bucket to curl the thumb?
Good day JT Do you have a hydraulic schematic for that valve section, that will help us to help you a great deal. What you suggest seems feasible if you do not have a schematic, try to get hold of one please. Kind regards Uffex
I haven’t seen a proper schematic for the valve sections in question. This is the best I have at the moment. The resolution of the manual I downloaded is quite poor.
Good day JT Leave that one with me a while, I will try to make some suggestions for you. Kind regards Uffex
The manual has a set by step disassembly of the tip/tilt valve sections. This may be of help.
Good day JT Please take a look at the attched so we may move foward there are some questions to answer. Kind regards Uffex
I’ll pull the top cover and and get these answers for you. I know most of them already, but are unsure about a couple.
To answer some generic questions. This auxiliary valve is fed by a dedicated gear pump (2 other variable displacement axial piston pumps serve all other functions) I’m not exactly sure where this input comes from exactly, but I presume to the gear pump Both sides of the auxiliary valve are mirror images of eachother. The same plug and line reliefs on both sides of each respective spool. The auxiliary valve is a solenoid controlled, pilot operated valve. The solenoids are controlled via joystick buttons. Ive labelled the below photo as best I can showing the destination of each pilot line. 1 goes to 1R, 2 to 2R and so on The numbers with an “R” (ie 1R) indicated that pilot line connects to the rear connection, on the back side of the valve where the arrow is. As mentioned, the valves are identical on both sides. This auxiliary system was certainly modified when this unit was converted to an excavator. The wiring to the top 2 solenoids (above 5&6 numbers) is messed up and that solenoid clearly isn’t being used. Those solenoids would have been used to control the tip function in the original configuration. I’m a little confused with the plumbing associated to the tip function on the aux valve. The output is routed to some sort of unit that also contains hoses that go to the swing motor. Close up of the tip spool hose designation/swing motor hoses
The tilt function outputs are routed through hard lines that are capped at the bulkhead hear the boom. These are by far the easiest to connect the thumb plumbing to Can’t leave out a photo of my “helper”
I located in the manual the info pertaining to what solenoid controls which function. It’s clearly evident that when the excavator conversion was done, things were moved around/modified. The schematics are certainly useful to help understand the original function, but aren’t much help in reality as things have been changed. In actuality, solenoid 3/4 have been configured to operate the old “tilt” spool. I think at this point my best course of action would be to figure out if I can replace the 2 plugs (flow control valve) in the “tilt” spool with 2 line relief valves. I’m a little apprehensive to try to use the “tip” spool as I just don’t understand the current plumbing and fear that it is somehow being used in conjunction with some other function. Other than reaching out to Husco directly (still awaiting a reply) is there any other guru that might be able to confirm relief valve compatibility? Here is the ID tag on the auxiliary valve.
Good day JT Your 227 has timber shear hydraulics I will try to get some more information in this respect, I suggest we just focus on the slice with the port relief valves and the two output lines from this slice. If we can activate that circuit and control the pressure we are 80% to acheiving control. If your information is in digital format and you post it to me I may be able to improve the quality. I will PM my email. Like your helper I have much the same. Kind regards Uffex
Good day JT I have studied the photo's can you confirm that when you activate the buttons the output lines become active? Kind regards Uffex
Currently I have the right joystick bottons wired to control solenoid 3 and 4. This wiring is pretty simple and customizable to any set of solenoids. Solenoids 3 and 4 currently deliver pilot pressure to the original TILT valve. The TILT valve is plumbed to capped lines at the boom. This circuit is currently functioning properly. As I get seepage at each cap (loosened) with the respective button press. I think part of my confusion is the manual describes the original TILT circuit as being combined with the swing circuit. It states that the operator would depress a button then use the swing function on the joystick (Left Joystick left or right) to operate the TILT. Let go of the button and swing works normally. I suspect that the plumbing on my unit has been changed and the TIP output lines to the swing valve were originally connected to the TILT valve. (Duh lol). I don’t think there would be a need anymore for any additional (tilt/tip circuits) plumbing to be connected to the swing valve. Just need to figure out a way to properly cap it.
Good day JT To keep you posted the attached is where we are at this time, there are a couple of conflicting aspects 1/- the shock valves having refill function as we cannot be sure unless we get numbers to refer 2/- according to your investigation the pilot lines for the valve terminate at the solenoids this conflicts with the circuit diagram which gives a remote control valve. A solenoid switching your thumb in each direction maybe not so nice to use but let us take one step at a time. Note the illustrations may not be pricise however the principle is as you will find on your machine. kind regards Uffex
In response to the first conflict you describe: The manual describes the main valve line relief valves as having a makeup function. The manual then describes the auxiliary line relief valves as operating the same as the main valve reliefs, although it doesn’t explicitly say the auxiliary reliefs have that same makeup/refill function. I can’t imagine an line relief valve that would be used in a system where makeup oil wasn’t also provided to the vacuum side. That seems like a necessary function. Regarding the second conflict: I would love to have a variable style switch to control the thumb, but this is a budget project and I’m trying to make what I have work (safely). I’m sure with some different techniques, for example using the bucket to make the fine pressure adjustments when picking something up, it can still be very functional.
Good day JT Looking ahead, it may be worth considering operating the thumb in combination with the bucket, working the same as a grab. Kind regards Uffex
I’ve managed to resolve this issue. For the last year I’ve been operating the thumb with the “Tip” spool on this valve. I had simply capped off the “tilt” ports and hoses to the swing valve. The issue with this is that I lost the ability to swing while tracking. It was annoying at times but mostly manageable. I recently purchased on old 227 as a parts machine. I salvaged the tip spool from its Husco valve and traded the tilt spool out for it. This led to some minor quirks with the swing and thumb operation. I don’t think the tip spools were meant to be sandwiched together. The solution was to install the old tilt spool between them. It seems to have fixed the issue and everything seems to work properly. The only minor issue I noticed is the lower valve seems to be receiving less flow. I originally had the thumb function plumbed to the lower spool but it resulted in very slow operation. I switched the lines with the swing and everything works great. Needed a few pieces of threaded rod to sandwich the now thicker valve stack.
Then I promptly put the old girl to work doing some drainage.
Great follow-up. Cool you got it sorted out. That's a fine looking old unit.
To clarify, I tried sandwiching both tip spool directly together which led to some quirks. This would have been the ideal configuration as the valve stack would have remained the same height. With the valves in this configuration the thumb and swing functions were cross controlling each other. The house would swing to the right properly while tracking but would only swing left and continue to swing left almost uncontrollably when the thumb was operated. I’m happy to have fingered this out. I’ll be re selling this unit in a couple years once my basement is dug and other major landscaping projects are completed.
I’ll pretend that the meandering nature of the ditch was intentional. I’m certainly not an operator.
Artistic flair...no straight lines in nature!
Good day If you need more help a hydraulic schematic of your machine is a necessity. kind regards Uffex
Put the machine through some good work over the past few days taking advantage of the unseasonably mild weather. I’m so happy the hydraulics are working as they should. Just getting some cleared areas cleaned up. I’d made a mess in these area running my underground hydro and harvesting sand for the septic field. So “before” pics I had lots of downed trees and mounds to clean up.
Will continue to spread out the sand across the boggy low area and will get some ground cover planted next spring. I’m sure wishing I had a D3 or D4 dozer! My brush piles are swelling. Need to burn them soon!