Colt Case Ingersoll Garden Tractors

I think this is the section I should post in. Guys, I have a tiny backhoe that came off the smallest excavator I have ever seen. (It was a SS16 by Kobelco) I have fabbed up all the mounts to put it on my 646, but the hydraulic feed from my PTO is way too much pressure, I think. It is super jerky, to the point it is useless. Is there a better place to tap into that maybe has less pressure? I am at a loss here. I have put reducers in, and no change. I'd really like to get this sorted out so I can start using it to plant some small trees I have, and other light work. Any suggestions for a less....robust source of hydraulic pressure?--------Metalguy

Here is a pic of the tiny backhoe:

Couple things to check...
Can you find out what the operating pressure, and pump flow was on the donor machine?

Is the valve stack you have on there able to handle the back pressure, or is it going straight back to the tank?

I run my 646 basically at idle, or just above for the D100. The cylinders on your hoe are a fraction of the size of that, so they're going to move FAST if you don't have flow limiters. As it is, the Case unit has flow limiters on the swing circuit, and it's still faster then you want most times.

That's a good looking setup, and will beat the hell out of a shovel any day if you can tame it...

@metalguy Unfortunately I don’t have the expertise to answer your question and I’m not sure if this will be helpful but I looked through my books and took some pictures of the plumbing for my D100 on my 648. We’re having a rain storm at this moment but if you think it would be helpful to you I’d be glad to get some pictures of how my tractor is plumbed this weekend.

Toolslinger wrote: ↑Thu Jan 25, 2024 7:13 pm Couple things to check...
Can you find out what the operating pressure, and pump flow was on the donor machine?

Is the valve stack you have on there able to handle the back pressure, or is it going straight back to the tank?

I run my 646 basically at idle, or just above for the D100. The cylinders on your hoe are a fraction of the size of that, so they're going to move FAST if you don't have flow limiters. As it is, the Case unit has flow limiters on the swing circuit, and it's still faster then you want most times.

That's a good looking setup, and will beat the hell out of a shovel any day if you can tame it...

I agree with you Toolslinger. I run mine just above idle when I use the hoe. The swing circuit on mine is very touchy. If you move the lever to much it can hurt you. Harry

I had thought of tapping into the three point circuit for mine, as I believe it has lower flow? I have tried flow limiters, but the difference is negligable at best. I'll have to see if I can find specs on the original pump, and such. Maybe I can run a hydraulic motor off the PTO for it's own pump? LOL. The valve stack has power beyond, so it ends up going back to the tank. -----Metalguy

metalguy wrote: ↑Thu Jan 25, 2024 5:29 pm I think this is the section I should post in. Guys, I have a tiny backhoe that came off the smallest excavator I have ever seen. (It was a SS16 by Kobelco) I have fabbed up all the mounts to put it on my 646, but the hydraulic feed from my PTO is way too much pressure, I think. It is super jerky, to the point it is useless. Is there a better place to tap into that maybe has less pressure? I am at a loss here. I have put reducers in, and no change. I'd really like to get this sorted out so I can start using it to plant some small trees I have, and other light work. Any suggestions for a less....robust source of hydraulic pressure?--------Metalguy

Metalguy,

I think you are confusing pressure with flow. The very first 644/646 loader/backhoes had no flow restrictors and the swing of the D100 was way too quick even at low rpms. The pressure should not be an issue as I would expect the stack valve on the hoe would have a relief. I would suggest a flow control (not just a restrictor) that will return excess oil to the tractor hydraulic system.

Bob

Howdy!

First off, that is a really nice looking setup for your loader / backhoe

I tried a quick Google for Kobelco SS16 and didn't get any hits for that specific model -

The Kobelco USA website shows an SK17SR Mini Excavator - but I don't know how that would compare with your donor machine... If it was similar, the specs for the SK17 show it has 2 variable displacement pumps (main circuits) + 2 additional gear pumps - 1 for pilot/servo the other - ? (possibly the brake circuit on the travel motors or a cooling fan circuit)

I mention it because if you are using the control valves from the donor machine it would make a difference what type of pumps it had and what type of pump you have in your loader. Systems with variable displacement pumps are usually set up differently than ones with gear pumps. (Closed Center vs Open Center systems) So it might be worth a little more investigation into the original hydraulic system.

Just my 2 cents...

I agree with what others have said. Your problem isn't pressure, it's flow: too much of it.

If you put in flow limiters and it didn't help, then your flow limiters are still too big. Get smaller flow limiters, and that'll tame this beast.

Bob

I found an SK008 that looks like it's their smallest model, and seems about right (honestly, it looks a little bigger in the photos, but close). Cut sheet says it has gear pump for the main system, and variable displacement pumps for the travel. Pressure on that machine was 2600psi. Doesn't list the flow. Engine is nominally 10hp. Perhaps the SS16 is a gray market machine that we're not going to see cut sheets on easily.

That would lead me to believe it can handle the Case output just fine. I would ask again if you plumbed the valve stack outlet straight back to the tank? If you didn't, then the oil that should just be free flowing to 0 pressure is going to hit the reliefs down stream, and could cause issues. The early d100's were made to go back in series. When I had to replace my control valves the manufacturer was explicit that it couldn't handle that, and needed the tank line.

I believe the flow control may well be a good choice as well to control your speed issues.

CCIGT's had an optional Flow Control Valve for use with tillers. It allowed micro control of the travel speed while giving the all of the oil flow to the tiller. The FCV was installed between the PTO return line and the Travel Control Valve. The FCV could be quickly set to divert all of the flow to the tank and starve the TCV. The back hoe plumbing would be opposite, when using a FCV, diverting some of the flow back to the travel control valve instead of all of the flow going to the hoe.

I did a search and found replacement gear pumps , searched the part number and and . I finally found a displacement of 7cc per revolution . Most little deisels in that type of machine I see looking it up are limited to 3000 rpm . So max output of the pump would be 7cc x 3000rpm less 10% when warm .
= about 1900cc per min . or 1.9 litres per min or 0.501 gpm
Assuming I got the right pump of which I could only find 2 . The gear pump and the dual variable pitch pumps for the track drives.
Even the smallest Case pump displacement I have seen is 6 gpm which is 12 time the volume.
Hopefully @FUTZ can chime in on this as he know more than I do for sure .

DavidBarkey wrote: ↑Fri Jan 26, 2024 7:02 am I did a search and found replacement gear pumps , searched the part number and and . I finally found a displacement of 7cc per revolution . Most little deisels in that type of machine I see looking it up are limited to 3000 rpm . So max output of the pump would be 7cc x 3000rpm less 10% when warm .
= about 1900cc per min . or 1.9 litres per min or 0.501 gpm
Assuming I got the right pump of which I could only find 2 . The gear pump and the dual variable pitch pumps for the track drives.
Even the smallest Case pump displacement I have seen is 6 gpm which is 12 time the volume.
Hopefully @FUTZ can chime in on this as he know more than I do for sure .

Good investigative work @DavidBarkey - Twin variable pumps for travel and a gear pump for digging functions...

It might be nice to find a Case Ingersoll flow control valve, but there are generic versions too... up here in the Great White North we can get generic ones from Princess Auto (Does Harbor Freight sell hyd. components?)

RoamingGnome wrote: ↑Fri Jan 26, 2024 10:16 am

DavidBarkey wrote: ↑Fri Jan 26, 2024 7:02 am I did a search and found replacement gear pumps , searched the part number and and . I finally found a displacement of 7cc per revolution . Most little deisels in that type of machine I see looking it up are limited to 3000 rpm . So max output of the pump would be 7cc x 3000rpm less 10% when warm .
= about 1900cc per min . or 1.9 litres per min or 0.501 gpm
Assuming I got the right pump of which I could only find 2 . The gear pump and the dual variable pitch pumps for the track drives.
Even the smallest Case pump displacement I have seen is 6 gpm which is 12 time the volume.
Hopefully @FUTZ can chime in on this as he know more than I do for sure .

Good investigative work @DavidBarkey - Twin variable pumps for travel and a gear pump for digging functions...

It might be nice to find a Case Ingersoll flow control valve, but there are generic versions too... up here in the Great White North we can get generic ones from Princess Auto (Does Harbor Freight sell hyd. components?)
flow control.jpg

In the The Surplus Center is a good outlet for hydraulics and other industrial goodies.

I did try a flow reducer valve, but I think I should try one like I have on my 446 I use for tilling. I would have to plump the return to the reservoir, but that shouldn't be a big deal...The way the stack is plumbed it has the pto in both sides, so when it is on, it can flow through, if that makes any sense. ---------Metalguy