Thomas Backhoe

[Jyuma]

I wish it were that easy. The #6 valve has a “service port restrictor“ connected to both working ports and they are male -10 ORB on one end and female -10 ORB on the other. I need an adapter to go from the new valves female work port size of -8 ORB to the existing male “service port restrictor -10 ORB. Then everything else will connect fine.
Here is a photo of the “service port restrictor” with the JIC fitting attached.

In the photo above you can see the JIC fitting which connects to the right side of the “Service Port Restrictor“ via a -10 ORB. The JIC side is where the hydraulic line connects. The left side of the “Service Port Restrictor“ connects directly to the valve. The old valve was -10 ORB and the new valve is -8 ORB. I need an adapter to go from male -8 ORB to female -10 ORB.

Does anybody know why the valve that controls the “swing“ would require flow restrictors? Is it because the hydraulic cylinders that control the swing are small and they require less flow?
What would happen if I eliminated the flow restrictors and connected the hydraulic lines directly to the valve via a standard ORB/JIC fitting?

 

[SkidRoe]

Does anybody know why the valve that controls the “swing“ would require flow restrictors? Is it because the hydraulic cylinders that control the swing are small and they require less flow?
What would happen if I eliminated the flow restrictors and connected the hydraulic lines directly to the valve via a standard ORB/JIC fitting?

The problem is the inertia that the boom gains while you are swinging it. If you were swinging the boom at full speed and suddenly released the lever to neutral, the interia in the boom acting on the swing cylinders would continue to build pressure as the boom suddenly decelerates. The pressure exerted can get high enough to blow lines or even the seals out of the valve. We found this out the hard way when we were fixing up our previously enjoyed (mechanic's special) Case backhoe. We ended up plumbing relief valves into the return lines from the swing cylinders to keep the pressure in check. Your flow restrictors do the same thing by controlling the max swing speed of your boom. Now that I think about it, the restrictors do not have to go right at the valve. Is there enough room to mount them out at the swing cylinders? Hope this helps.

 

[Jyuma]

The problem is the inertia that the boom gains while you are swinging it. If you were swinging the boom at full speed and suddenly released the lever to neutral, the interia in the boom acting on the swing cylinders would continue to build pressure as the boom suddenly decelerates. The pressure exerted can get high enough to blow lines or even the seals out of the valve. We found this out the hard way when we were fixing up our previously enjoyed (mechanic's special) Case backhoe. We ended up plumbing relief valves into the return lines from the swing cylinders to keep the pressure in check. Your flow restrictors do the same thing by controlling the max swing speed of your boom. Now that I think about it, the restrictors do not have to go right at the valve. Is there enough room to mount them out at the swing cylinders? Hope this helps.

Oh... now I understand what happened to me several years ago when I was in a hurry and I blew the back right off one of the swing cylinders. I guess it can be a problem even with the restrictors connected.
I already ordered a set of ORB to JIC fittings to connect the hoses directly to the valve (no restrictors) but now I'll continue trying to locate the adapters I need to keep the flow restrictors in the circuit. I don't have room to plumb them at the cylinder so I'll concentrate on those adapters.
Any ideas about where the best place is to buy adapters?
Thanks

 

[Wm McNett]

Oh... now I understand what happened to me several years ago when I was in a hurry and I blew the back right off one of the swing cylinders. I guess it can be a problem even with the restrictors connected.
I already ordered a set of ORB to JIC fittings to connect the hoses directly to the valve (no restrictors) but now I'll continue trying to locate the adapters I need to keep the flow restrictors in the circuit. I don't have room to plumb them at the cylinder so I'll concentrate on those adapters.
Any ideas about where the best place is to buy adapters?
Thanks

The restrictor is simply a fitting with a small hole in it, correct? Why not have turn a piece of round stock down to press into the fitting you have ordered and drill the same size hole in the middle of it or weld the hole in the fitting closed then drill the small hole in it? No bulky adaptor needed.

 

[Wm McNett]

The restrictor is simply a fitting with a small hole in it, correct? Why not have turn a piece of round stock down to press into the fitting you have ordered and drill the same size hole in the middle of it or weld the hole in the fitting closed then drill the small hole in it? No bulky adaptor needed.

another option you have over looked is to swap valve 6 with valve 1, 2, or 5 and keep your original flow restrictors

 

[Wm McNett]

another option you have over looked is to swap valve 6 with valve 1, 2, or 5 and keep your original flow restrictors

after a second look, swap with valve 2, 1 & 5 have some port thingy

 

[Jyuma]

after a second look, swap with valve 2, 1 & 5 have some port thingy

You are right... I could swap with the #2 valve... but that would mean taking all the valves apart again. No big deal from a time stand-point but what about all those O-rings that have already been compressed twice. Would I need to use all new O-rings?
We are supposed to get hit by a hurricane tomorrow... swapping valves might be a good way to ride out the storm.

 

[Wm McNett]

You are right... I could swap with the #2 valve... but that would mean taking all the valves apart again. No big deal from a time stand-point but what about all those O-rings that have already been compressed twice. Would I need to use all new O-rings?
We are supposed to get hit by a hurricane tomorrow... swapping valves might be a good way to ride out the storm.

If they were old O-rings that were hard and brittle, I'd say yes, replace them, but their new and I do not think you will have a problem.

 

[jerry]

If they were old O-rings that were hard and brittle, I'd say yes, replace them, but their new and I do not think you will have a problem.

On my old davis backhoe the restrictors are simply flat washers that are put in the valve body before you screw in the adaptor. the originals were .090 thick and threaded but the ones i have made since I do not thread , just place in the hole.

 

[Jyuma]

On my old davis backhoe the restrictors are simply flat washers that are put in the valve body before you screw in the adaptor. the originals were .090 thick and threaded but the ones i have made since I do not thread , just place in the hole.

That's what I love about this forum. Where else could one obtain this wealth of knowledge just for the asking?
I looked inside the restrictor and there is a single hole approximately .040 dia. in the center of the what appears to be a movable plate. However, the plate is not flat (like a washer) but appears more like the top of a castle nut. In addition, the plate slides up and down between stops much like a piston slides up and down in it's cylinder. This makes me believe there is more to these restrictors than just a simple hole.
Assuming that I would be unable to locate an adapter for male -8 ORB to female -10 ORB my best option appears to be to swap the #2 and #6 valves.
Thanks for all the great ideas. Each of you are an invaluable source of knowledge and support.

 

[jerry]

That's what I love about this forum. Where else could one obtain this wealth of knowledge just for the asking?
I looked inside the restrictor and there is a single hole approximately .040 dia. in the center of the what appears to be a movable plate. However, the plate is not flat (like a washer) but appears more like the top of a castle nut. In addition, the plate slides up and down between stops much like a piston slides up and down in it's cylinder. This makes me believe there is more to these restrictors than just a simple hole.
Assuming that I would be unable to locate an adapter for male -8 ORB to female -10 ORB my best option appears to be to swap the #2 and #6 valves.
Thanks for all the great ideas. Each of you are an invaluable source of knowledge and support.

You must have a new improved version of restrictor, perhaps the movement is too allow a faster flow and then as the plate moves in the direction of flow it will give it a cushion effect. I had to put a very small one in the valve for the dipper stick. I think I made the hole only.075 but it works just right now.
You're right about the forum too, it has saved me a ton of money in repairs.

 

[jerry]

You must have a new improved version of restrictor, perhaps the movement is too allow a faster flow and then as the plate moves in the direction of flow it will give it a cushion effect. I had to put a very small one in the valve for the dipper stick. I think I made the hole only.075 but it works just right now.
You're right about the forum too, it has saved me a ton of money in repairs.

I was mistaken , it was the boom I put the small restrictor in this year.

 

[Jyuma]

I was mistaken , it was the boom I put the small restrictor in this year.

I switched the #2 and #6 valves. Now I'm in wait mode again for the -8 ORB to 3/4 JIC.
Here are some pictures of the valve assembly after the switch. Notice the port restrictors connected to what is now valve #6 .

Below is a closer look at valve #1 and #2. Notice the plate with the single flat-head screw on the top of valve 2. This is the hold-down plate for the new spool seal design. (I countersunk the hole so I could provide a flat surface for the linkage assembly block to bolt to. I also added a plate to valve #1 to serve as a spacer to keep the mounting surfaces even. The screws from the linkage assembly block (there are only 3) will pass through the holes in the plates and make them captive between the mounting block and the top of the valve.

Here's an interesting side note: Do you see the cylindrical tubes (rusty and pitted) connected to the tops of spool #'s 1,2 and secured by roll pins? Notice the roll pin on #1 sticks out way past the cylinder... this portion of the roll pin aligns with a slot in the linkage assembly block and prevents the spool from spinning. Spool #1 is the only one that is prevented from spinning in this fashion... I have no idea why.

 

[Tazza]

I switched the #2 and #6 valves. Now I'm in wait mode again for the -8 ORB to 3/4 JIC.
Here are some pictures of the valve assembly after the switch. Notice the port restrictors connected to what is now valve #6 .

Below is a closer look at valve #1 and #2. Notice the plate with the single flat-head screw on the top of valve 2. This is the hold-down plate for the new spool seal design. (I countersunk the hole so I could provide a flat surface for the linkage assembly block to bolt to. I also added a plate to valve #1 to serve as a spacer to keep the mounting surfaces even. The screws from the linkage assembly block (there are only 3) will pass through the holes in the plates and make them captive between the mounting block and the top of the valve.

Here's an interesting side note: Do you see the cylindrical tubes (rusty and pitted) connected to the tops of spool #'s 1,2 and secured by roll pins? Notice the roll pin on #1 sticks out way past the cylinder... this portion of the roll pin aligns with a slot in the linkage assembly block and prevents the spool from spinning. Spool #1 is the only one that is prevented from spinning in this fashion... I have no idea why.

I'm a bit late on a reply, but i agree with using the 'old' o-rings. If they haven't been installed for a long period of time they are fine to re-use. Only age and heat make them harden up and leak if you try and use them again.
Glad you pointed out about the rusty bits on the end of the spools. I was starting to think the new control block segments you got didn't come with new spools, i was thinking that was very odd, but my mind was put at ease.

 

[SkidRoe]

That's what I love about this forum. Where else could one obtain this wealth of knowledge just for the asking?
I looked inside the restrictor and there is a single hole approximately .040 dia. in the center of the what appears to be a movable plate. However, the plate is not flat (like a washer) but appears more like the top of a castle nut. In addition, the plate slides up and down between stops much like a piston slides up and down in it's cylinder. This makes me believe there is more to these restrictors than just a simple hole.
Assuming that I would be unable to locate an adapter for male -8 ORB to female -10 ORB my best option appears to be to swap the #2 and #6 valves.
Thanks for all the great ideas. Each of you are an invaluable source of knowledge and support.

The castlated section on your restrictor plate is to ensure that the flow is restricted in one direction only. It's a more elegant solution than just a simple orifice.
Unless you plan on making your living with your hoe attachment, the simple orifice would likely work just fine.
Cheers, SR

 

[Tazza]

The castlated section on your restrictor plate is to ensure that the flow is restricted in one direction only. It's a more elegant solution than just a simple orifice.
Unless you plan on making your living with your hoe attachment, the simple orifice would likely work just fine.
Cheers, SR

Even flow resrictors could be installed at the ends of the cylinders. There have been a few people that have slowed them down by drilling a small hole in a piece of round stock, if its too slow, drill it one size larger till you get the speed you want.

 

[Jyuma]

Even flow resrictors could be installed at the ends of the cylinders. There have been a few people that have slowed them down by drilling a small hole in a piece of round stock, if its too slow, drill it one size larger till you get the speed you want.

SkidRoe... I don't doubt that you are 100% correct about the restriction being in only one direction but I'm curious as to the reason for doing so? Can I assume that because there are two flow restrictors (one in each port) that the effective restriction will in fact be in both directions?
In retrospect, I suppose that a simple hole in a plate... one in each port... would in effect double the restriction but if each restrictor will only restrict in one direction, then the total restriction would not be cumulative but rather equal to the individual restriction of only one port restrictor at a time as determined by direction. Darn clever of them.

 

[Jyuma]

SkidRoe... I don't doubt that you are 100% correct about the restriction being in only one direction but I'm curious as to the reason for doing so? Can I assume that because there are two flow restrictors (one in each port) that the effective restriction will in fact be in both directions?
In retrospect, I suppose that a simple hole in a plate... one in each port... would in effect double the restriction but if each restrictor will only restrict in one direction, then the total restriction would not be cumulative but rather equal to the individual restriction of only one port restrictor at a time as determined by direction. Darn clever of them.

There is joy in Mudville... the valve is back in the machine and there are no leaks. The controls are working better than ever.

 

[Jyuma]

There is joy in Mudville... the valve is back in the machine and there are no leaks. The controls are working better than ever.

Opps... I was working all the controls when suddenly there was a big puddle of hydro on the ground. Looks like I blew something in the bucket circuit. Probably a hose or a fitting but I'm in no mood to look for it tonight. I'll find it in the morning... it probably won't be a big deal.

 

[Tazza]

Opps... I was working all the controls when suddenly there was a big puddle of hydro on the ground. Looks like I blew something in the bucket circuit. Probably a hose or a fitting but I'm in no mood to look for it tonight. I'll find it in the morning... it probably won't be a big deal.

Here i was, all happy that it was working so well, then i read the next post saying it piddled a bit on the floor. Hopefully just a fitting *crosses fingers again*