downsizingnow48
Elite Member
Yep. Get the valve I linked to. All will be good.
Backhoe Building a thumb for a model 48 Backhoe
- Thread starter DanMc77
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Pat, I appreciate your recommendation. I looked back over the earlier posts where the spool valve was discussed. Here's one that looks super good, though a bit pricey, recommended by Mr Downsizing:
1 Spool Prince SV Sectional Hydraulic Control Valve Open Center w/Power Beyond | Stack Valves | Hydraulic Valves | Hydraulics | www.surpluscenter.com
This one lets you choose the specific spool valve. The last choice has metering with adjustable work port reliefs. Though more expensive, that would eliminate the separate relief valve and two hoses. Also, it has ports on the top and the bottom to help with layout. It ends up being $273, but I think it would be a wash by eliminating the external relief. Being stackable, I could then add another spool section if I ever want to add another cylinder.
1 Spool Prince SV Sectional Hydraulic Control Valve Open Center w/Power Beyond | Stack Valves | Hydraulic Valves | Hydraulics | www.surpluscenter.com
This one lets you choose the specific spool valve. The last choice has metering with adjustable work port reliefs. Though more expensive, that would eliminate the separate relief valve and two hoses. Also, it has ports on the top and the bottom to help with layout. It ends up being $273, but I think it would be a wash by eliminating the external relief. Being stackable, I could then add another spool section if I ever want to add another cylinder.
downsizingnow48
Elite Member
Yep that is what I had in mind. I think it is the most straightforward solution to the situation.
texasranger556
Platinum Member
And whatever you can do to stay away from pipe thread...do it!
LOL. Pat is Mr DownsizingNow48. Same guy.
Found a few hours this weekend to make a bit more progress on the thumb. Got some paint on the thumb itself as it is hopefully completed. The pivot pin for the cylinder was machined. A zerk was put in the end and a hole was bored as with the bucket pin so it can easily be greased from the side. The pin length was extended a bit on one end so that it's easy to reach the zerk through the access hole in the side of the thumb, but recessed enough so it's protected. I didn't have to bore a recess into the pin since the thumb provides the needed protection. Circle clips hold this pin into place.
The dipper bracket on the other end of the cylinder was welded up and drilled. I had to run the drill bit back through pivot bore in the bracket since things shifted just a little bit after welding it together. The tail of the bracket had to be trimmed off because it interfered with the dipper stop. I didn't get a pic of it after that trimming.
The plate that covers the spool valve connections was removed so I could get a look at how to gain access to the main hydraulic lines and get an idea of what I'm in for when it comes to plumbing in the new spool valve. This will be quite easy. The two larger fittings on the right are the lines that run over to the tractor. I just need to take off the high pressure line and insert the spool valve. I may even be able to get it cut and connectors inserted without replacing the whole hose.
We put bucket back on with the thumb and strapped it in place. My son ran the machine for a while digging out a stump and it ran nicely. It was comforting to see that the retracted thumb didn't get in the way of anything while he was working with it.
The dipper bracket on the other end of the cylinder was welded up and drilled. I had to run the drill bit back through pivot bore in the bracket since things shifted just a little bit after welding it together. The tail of the bracket had to be trimmed off because it interfered with the dipper stop. I didn't get a pic of it after that trimming.
The plate that covers the spool valve connections was removed so I could get a look at how to gain access to the main hydraulic lines and get an idea of what I'm in for when it comes to plumbing in the new spool valve. This will be quite easy. The two larger fittings on the right are the lines that run over to the tractor. I just need to take off the high pressure line and insert the spool valve. I may even be able to get it cut and connectors inserted without replacing the whole hose.
We put bucket back on with the thumb and strapped it in place. My son ran the machine for a while digging out a stump and it ran nicely. It was comforting to see that the retracted thumb didn't get in the way of anything while he was working with it.
Drenalin01
New member
- Joined
- Apr 29, 2018
- Messages
- 2
- Tractor
- John Deere 4310 with 48 backhoe
So what exactly did you use for parts to plumb hydraulics and do you like how it works
I have 48 backhoe and looking to do the same ...hydraulic thumb just need a little help with hydraulic parts and piston thanks
I have 48 backhoe and looking to do the same ...hydraulic thumb just need a little help with hydraulic parts and piston thanks
I'm still working on it. Here's the valve I got. It's pricey, but it's a segmented valve, so I could insert another spool any time I wanted to. Also it includes the work port reliefs, so it makes the whole installation a snap. Read through the whole thread and you'll find the cylinder that I'm using. Over the next couple weeks I'll be working on getting the hydraulics installed. Weds night I'm thinking that I'll tack weld the cylinder bracket to the dipper. I still need to figure out how to get the final welding done on the cylinder bracket. I could weld it with my wire-feed welder, but I don't have gas, I'm a mediocre welder, and it comes out kind of sloppy. I want to see perfection in this weld, so that's not me. Plus, the wire-feed welder won't get the penetration needed for a good strong weld.
The new spool valve arrived and I assembled the three segments. It's nice that there are additional side ports for in/out that can be used if the top ports are inconvenient. My son-in-law recommended that I mask the ports and put a couple coats of paint on it. Seems like a good idea.
I am thinking that I should be able to remove the foot pan on the backhoe and mount this right below. I've never taken off the foot pan, so I'll take it off tomorrow night and get a look.
I have a welder scheduled for Friday morning to stop over and weld the cylinder bracket onto the dipper. This guy specializes in welding on heavy equipment. This is the same guy that used a thermal lance to blow a hole through the dipper pivot pin that was rusted into the boom and stuck.
I am thinking that I should be able to remove the foot pan on the backhoe and mount this right below. I've never taken off the foot pan, so I'll take it off tomorrow night and get a look.
I have a welder scheduled for Friday morning to stop over and weld the cylinder bracket onto the dipper. This guy specializes in welding on heavy equipment. This is the same guy that used a thermal lance to blow a hole through the dipper pivot pin that was rusted into the boom and stuck.
I have a question for you hydraulic masters. When I look at the doc that came with this valve, I see that I'll need to make 5 connections:
1, 2: Work ports to the thumb cylinder - that's easy.
3: In - this is the high pressure line coming from the tractor that formerly went to the backhoe, will now go to this new valve.
4. Power Beyond - this is the high pressure coming out of the new valve. I'll plumb this to feed the backhoe, so connections 3 and 4 are basically inserted into the high pressure line coming from the tractor.
5. Out - The documentation implies that it needs to go to the tank. Do I need this? I'm thinking not, since the backhoe currently runs with only two hoses, so why can't the thumb valve be fed with two hoses? Or is it different if the valve supports power beyond? This may be redundant with questions I asked earlier, so please be patient with me.
1, 2: Work ports to the thumb cylinder - that's easy.
3: In - this is the high pressure line coming from the tractor that formerly went to the backhoe, will now go to this new valve.
4. Power Beyond - this is the high pressure coming out of the new valve. I'll plumb this to feed the backhoe, so connections 3 and 4 are basically inserted into the high pressure line coming from the tractor.
5. Out - The documentation implies that it needs to go to the tank. Do I need this? I'm thinking not, since the backhoe currently runs with only two hoses, so why can't the thumb valve be fed with two hoses? Or is it different if the valve supports power beyond? This may be redundant with questions I asked earlier, so please be patient with me.