hydraulic pto pump coupling 3/4"?

[myyaz33]

The pto pump I have for the backhoe I am restoring appears to have a 3/4" shaft and I am having a tough time trying to locate a PTO Coupling for that size of shaft. Is this an uncommon size? It seems like everyone carries everything but that at the local supply stores and I can't find any online either. Any help would be appreciated.

Marty

 

[shaley]

Are you trying to get to a 1-3/8 x 6 spline from a 3/4 round with a flat?

 

[Farmerford]

Is Surplus Center Item# 1-2456 what you need?

 

[myyaz33]

FarmerFord,

That may be it, not sure why I did not run across it in my searching the Surplus Center site. You might check out the attached picture to see what you think.


Shaley,
As you will see in the attached picture it is 3/4 round and keyed.

 

[myyaz33]

As you can tell, I don't really know much about hydraulics. From the picture is there any way to tell the specs of the pump or who made it?

 

[Farmerford]

Marty:

That might be an old Gresen vane pump. The "TB" stamped on it was used by Gresen (and I think still is) for a line of general purpose pumps for farm equipment, construction equipment, etc.

If so, it probably has a maximum pressure of around 1500 psi and is designed to run around 1250-1500 rpm (because they were often driven from the camshaft on the tractor engine, which as you know turns at one-half crankshaft speed).

I can't tell the gpm from the picture. Is that a "2" stamped in the case? Could mean 2 gpm, but that seems pretty low. I also see a "17", and that seems pretty high for that size pump. Whatever the gpm, if you drive it with a pto at 540 rpm it will produce about 1/3 of the rated gpm, which will probably make the backhoe slow.

That pump appears to be set up for an SAE "B" two-bolt mount (3 1/4" dia) and many of that type pump either has no input shaft bearing (it depends on the driving shaft to keep the input shaft centered) or more likely a simple sleeve bearing that will not carry much radial (side) load. If you hang such a pump off the PTO shaft the side load of the pump weight and force from the torque bar, hoses, etc. may be more than the bearing can stand. You might want to get a pump mount (Surplus Center has them) and make a fixed mount for the pump that bolts to a stationary drawbar or some other part of the tractor rear end.

Good luck with the restoration. What kind of backhoe is it? What kind of tractor was it on before? Are you restoring it for sentimental purposes or to use? Pictures would be great.

Chuck Ford

 

[SPYDERLK]

As you can tell, I don't really know much about hydraulics. From the picture is there any way to tell the specs of the pump or who made it?

Be sure to determine whether the direction of rotation required by the pump is correct for direct drive by the PTO.
larry

 

[Farmerford]

Marty:

Look at Surplus Center Item# 9-1214-CW. That is a modern Gresen vane pump. I'll bet you could call Gresen with the various numbers on your pump and they would tell you about it. If it is a Gresen TB, note a couple of things. The one at Surplus Center has ball bearings, so side loads are not a problem. Also, note that the Surplus Center model starts with the vanes retracted and they do not extend until 500 rpm. This means your pump (if the same) will not pump at all until it reaches 500 rpm. Finally, I said the mount was SAE B, but it appears it may be SAE A.

Chuck Ford

 

[Farmerford]

Larry's advice may be best of all. Shaft rotation is typically stated from the position of facing the shaft that is to be driven or that is driving. Therefore, a CW pump can only be direct coupled to a CCW shaft, and vice versa. Most tractor PTO's are CW (when facing the shaft from behind the tractor looking forward). But your pump is also CW, and a CW pump on a CW PTO shaft will be turning backwards.

So you may never reach the issue of the size of your pump because you can't drive it from the PTO due to the direction of rotation. If that is the case, you should consider a new PTO driven pump such as those at Surplus Center.

Chuck Ford

 

[myyaz33]

Farmerford & SPYDERLK

Thanks for taking the time to help me out. Here is brief verview of what I know of the backhoe. I bought it off Ebay last summer knowing it was going to need some work. It is a Kubota model K-650. I have seen a few of these pop up on the forums recently and mine is in about the worst shape of them. Right now it is completey dismantled and getting sandblasted. The backhoe came off a Kubota L2250 parts tractor and I do plan on using it however not sure I will be able to use it on my B6100 Kubota. The K-650 backhoe manual doesn't mention the pump much except the following information. Operating Pressure for Digging 1,000psi , 6.9MPa & for Swing 1,000psi , 6.9 MPa & Stabilizer Spread 42"-48" 1067-1219. The original part number was 8842403 which crosses over to 70020-00168 nowadays. I am not really sure my pump is the original anyhow or even if it works...

It appears that the stamped number that looks like a 2 is actually a 3. It is upside down and reads 3+. After a closer look it appears there is a small "c" near the C.W. and on the side of the pump with the shaft I do see a C.C.W which is making me think the pump would be the correct one to mount to a CW pto shaft. Oh, although it is not in the pictures I do have a mount plate for the pump that I plan on modifying it to connect to the ROPS mount so it will be stable in use.

I have tons of pictures of the backhoe project and will be post them when I get a bit further along.

I have attached a couple updated pictures of the pump so now you can see the letters a little better. It does appear to be CCW doesn't it? Not sure why the first "c" is small on the side with all the numbers but the shaft side cleary shows CCW.

 

[SPYDERLK]

Farmerford & SPYDERLK
[snip]
I have attached a couple updated pictures of the pump so now you can see the letters a little better. It does appear to be CCW doesn't it? Not sure why the first "c" is small on the side with all the numbers but the shaft side cleary shows CCW.

I think youre good for rotation and Im betting all the cases come marked CW and the other C is added when applicable. 540 is awful low rpm for a small hyd pump tho. I think the L2250 had 540/1000 PTO speeds. You may need the 1000.
larry

 

[myyaz33]

The backhoe had a sticker on it that did say run at 540-800rpm, but once again not sure this is the original pump. Time will tell, I guess. Fortunately I have 540-800-1000 PTO options on the B6100.

I think I will go ahead and take the pump to the local hydraulic shop and have them test GPM to see if it is working properly.

 

[myyaz33]

Never did take the pump in to get tested, but I finally got the backhoe rebuild complete and tested the pump tonight. Everything appears to be working properly. I will be posting in the Project section about the backhoe project. Thanks to all for helping me identify the specs on the pump.

 

[myyaz33]

Marty:
Whatever the gpm, if you drive it with a pto at 540 rpm it will produce about 1/3 of the rated gpm, which will probably make the backhoe slow.
Chuck Ford

FarmerFord, you certainly called this one. As you may have saw in the Project forum, I got the Kubota K-650 backhoe restored and have begun using it. The problems is that running the Gresen TB-3 vane PTO pump just makes things slow as I only have the 540 pto speed on the TYM instead of the 3 speeds I had with the Kubota B6100.

I think my best alternative is to plumb to the rear remotes on my tractor. Any thoughts on this? The remotes should be around 2200psi but I think the hoe cylinders run around 1000psi. This has me a bit gunshy. The PTO pump is 3gpm vs my remotes at 5gpm. I have no idea what the backhoe valves can handle as far as gpm.

 

[myyaz33]

Going to repost my last questions as a new thread in the Hydraulics forum as the topic no longer applies.