Live Hydraulic Frustration Continues

I took the live pump off my D and looked it over carefully. The governor side bearing had worn to .013" oversize, so I turned and bored a new one and pressed it in. Then I replaced the oil
seal, put it all back together and gave it a test. No good. It was slightly better but still very slow and weak. Again, if I pressurize the reservoir with compressed air, the hydraulics
operate fine, and the cylinder moves fast; but as soon as I take the pressure away, it's back to slow motion and no power. It couldn't even raise the plow.

So today I took it off again (I'm getting fast at this!) and took it apart so I could see the distributor's side seal. The previous bozo had welded the gear through the snap ring to the
shaft, so I had to do some careful grinding to remove it without during the shaft. I did very well and got it apart without hurting the shaft, I'm proud to say. I can see no place where
this thing is leaking. As far as I can tell the two seals are solid. Yet, oil comes out there when I pressurize it.

Now I cannot get it the rest of the way apart. The spring inside and the lever are in there, and I can't figure out how to pull them out. Darn, I hate stupid engineering like this.
Ridiculous modern stuff anyway. Grrr! Does anyone here have a suggestion who I could send this thing to to be rebuilt? I have to make a living in that shop, and this D is taking way
too long.

Or does anyone have a rebuilt one I could buy that I could trade this pump for? I'm at the end of my ideas and getting sorely frustrated.

Thanks for any help at all.

joel

P.S. I showed my email, so feel free to type directly if it's easier.
 
The small seal towards the ignition seals vacuum. The lip toward the outside. If it's flipped you draw in air not oil.
 
With gear-type hydraulic pumps, when the shaft bushings or bearings wear,the shafts and gears move away from the pressure side and the tips of the gear teeth chew away at the housing around the gears.

Although you made a new bushing and got the shaft centered in it's bore there will still be excessive gap between the tips of the teeth and the center section of the pump. That can be checked with a feeler gauge.

Also, how much wear/play is there at the side of the gears, you can check that with Plastigage.

More than a couple of thousandths gap at either area and the pump will act as you describe.

If there's excessive gap between the gear tips and the housing there's no way to repair it, only replace the worn parts.

Sometimes, special "oversized" gears are suggested, but how would that work with a fixed distance between the centerlines of the two shafts???
 
Doubt it will show you anything new

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I would be tempted to attempt true up the end plates and the sides of the gears . Then machine the center section thinner to make up the clearance.
Won't stop the oil from escaping past the teeth but will reduce the leakage between the gears and center section/end plates.
 
Surface grind them I suppose, leaving the housing, what, a thou taller maybe?

Thing is, having too much clearance should mean it never makes pressure, shouldn't it? because the oil would just squish by. Shouldn't matter whether the reservoir is pressurized
or not, seems to me. Why it won't suck oil is what gets me. Maybe I should make a tank that's higher than the pump so it gravity feeds to it.
 
What you say makes sense. But does it make sense that my pump makes good pressure when I force oil to it with compressed air? I'd think if it were worn to the point of letting the oil slip by the gears it would never make pressure, even when compressing the reservoir. My air only has about 80 lbs, but I was having the same effect as low as 30 lbs.
 
This pump has two seals on the distributor side and one on the governor side. I replaced single one the governor side. Is that the vacuum side you are talking about? I replaced it with the metal side in, rubber side out. Was that right?

Thank you, by the way. I sure appreciate it.
 
One tip I've read from a hydraulic guy on the net, to tell if a gear pump and is worn out (and losing all the pressure through clearance in the gears). Get it running and pumping on a load, and put your hand on the pump. it will be HOT. All the pressure loss is there and making heat.

To me it sounds like you're losing suction, gotta be an air leak somewhere. Pressurizing your reservior wouldn't make a worn pump work any better. That's in my mind anyway

Brandon
 
Yes, it's been a while since I worked on one of those pumps. The small single seal on the governor side.
 
The heat makes sense. So does the leak except that I found no hole when I pressurized it. (Not to say there is none, of course.) I did see oil coming out of the distributor side of the pump, which would mean the bearing and seals there are letting it by. That and checking the pump clearance will be my next tackle.

I hope I can get this going by the time the fields dry off from these rains we've had and are supposed to keep having. (Boy are there lakes in the fields this morning!!) I finished plowing the field with the 80 Tuesday, and we'll be seeding as soon as we can get it fitted. It took 28 hours to plow a 28 acre field! How would you like some Michigan stones? I spent more time picking rocks than turning over dirt. Wow. My dad actually reprimanded me for picking too many stones! Ha ha! That explains why Sanderson ground is so rocky. ;) I'd like to fit the dead furrows with my D--and probably the gullies now too--but I'm starting to doubt my mechanical abilities to get this pump figured out in time.
 
On your earlier post about 2 weeks ago I talked about replacing the seals on the governor end with 2 seals. These seals should have the garter springs facing away from each other.
Did you do that? I ask because you now say you replaced 1 seal on the governor end.
 
The governor end has only one seal on this pump, and there's no way two will fit there. I tried. The distributor end has one big double seal. When I went to Deere today to get a replacement they gave me two instead. I'm very sure this area is where the problem is. That old seal is dried and hard. I'm sure it was gasping bubbles into the system. Plus the bearing on that side is .010" oversize. The opposite bearing was .013" over, and I replaced that one. Shows my inexperience that I thought one would be worn but not the other. Sheesh. Anyway, between the sloppy bearing and the hard seal, no wonder it was leaking. Deere doesn't have the bearings anymore, so I'll turn one tomorrow like I did the other side, and then put it all back together and keep every toe and finger I've got crossed.

If I recall, you said to put the two seals together with the metal housing on the outside, am I right? With the rubber facing each other? Or should they be placed the same, with the rubber facing out?

I appreciate your help, Pete.

Joel
 
Joel,

It seems to me that your description of the two ends of the pump is wrong. The small end of the shaft is the governor end and the big end is the distributor end. Do you agree?

The governor end of the shaft originally had a double- lip seal that was 1/2" wide. The new seals are 1/4" wide and two are used. These seals are installed with the garter spring sides facing AWAY from each other.
 
The small end is the governor end, and the large end is the distributor end; but the distributor end has a double seal that's 5/8" wide and is replaced with two seals 5/16ths wide, and the small end--the governor end--has room for only one seal that's about 1/4" wide.
 
(quoted from post at 21:50:52 05/15/20) The small end is the governor end, and the large end is the distributor end; but the distributor end has a double seal that's 5/8" wide and is replaced with two seals 5/16ths wide, and the small end--the governor end--has room for only one seal that's about 1/4" wide.

Also, do you have a good gasket under the inlet fitting that has the little disengage lever in it?

Have you replaced the O-ring seal on the little disengage shaft?

If the pump IS, in fact drawing air that would be two prime places to leak.
 
I think in almost all instances like that, the seals oppose each other, one facing out to keep the air/dirt out, the other in, to keep the oil inside. At least that's my experience. If you had a worn out bearing, it would definitely make the seal leak on top of the bad seal. I learned that the hard way when I replaced a seal and not a bearing....and it leaked! Not a pump but you get the idea

Brandon
 
Joel,

You're right, my memory failed me.

The small seal on the governor end should have the garter spring toward the outside of the pump to prevent air from being sucked into the pump.
The large seals should be installed with the garter springs facing away from each other.
If the old small seal wore a groove in the shaft, try setting the new seal at a slightly different depth in the housing.
 
I had a good gasket until I ripped it the third time I took it apart. Ah well; I made that one, and I'll make another one when I put it back together. I'm putting the thirds and this cap on
with shellac like the instructions say. Seems like a good idea so far.

I didn't know about an o-ring in the on-off lever. I'll check that for sure now. I had pressurized the pump at one point and soap-sudsed the sections, but I don't remember if I
squirted on that spot or not.

Thanks gazillions.

Joel
 
Sure do. Thanks, Brandon. I really think I'm finally onto it this time.

I should take a video to show how fast I've gotten at taking all this apart--and then another putting it back together and timing it! Parts just a flyin! Ha ha!
 
It was actually worse than that under the seal. The somebody who had welded the gear to the shaft ground their weld and took good bites out of the shaft, undercutting it, so there was no way the seal could even contact all the way around. I filled it with my mig, carefully filed it, checking it with my dial caliper until I got it within a thou and a half or so. It seals now--there anyway.
 
Your fun with this pump reminds me of when I dug into the 80 transmission. This is wrong, that, and that and that, and oh, boy!

Brandon
 
Yeah. Oh. Boy. ;) The engaging collar is worn to the point where it cannot function. How in the world it ever wore that far is beyond me. I thought I was going to weld the little key-tab-things up with the mig and then file them down, but noooo.... it's cast iron. Great. Now why would they make that out of cast? It's not even a bearing surface. No wonder the things wear out. So tomorrow I get to machine a new one. I guess that's why I have my mill and rotary table. Heck, I might even put the die slotter to use for it--who knows.
 
Hey, I wanna thank you for pointing out that o-ring. It wasn't doing anything at all. In fact, I think it was the wrong size even, judging by the groove that's there. I'll get a new one
tomorrow and see how that fits.

Thank you very much for helping.
 
Ouch. Well if it's like the later pumps, the engaging parts aren't really supposed to engaged while the engine is running, so there really should be no wear on the parts, unless I'm envisioning it wrong? Man you're making me jealous having access to a mill. Took all the classes but have no real experience. But if I started complaining about that I'd go on for days

Brandon
 

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