I’ve got a six spline gear pump on the old Case. Now that I’ve replaced the valve, I can’t get any pressure from the pump. I’ve got great return flow up to the brand new oil filter, but out of the filter only about a tenth as much as going into it. My du-Al loader has a vertical tank which is full, and there’s a ball valve just before the filter that I use to check on the flow. My question is, does the pump suck fluid in from the bottom of the tank? I don’t see how the dribble it’s getting from gravity could be enough. The pump is about 20 years old but only has about 50 hours on it at most and was working when I replaced the valve. Any suggestions much appreciated.
No PTO pump pressure
- Thread starter CMR
- Start date
- Views: 10347
Leejohn
Elite Member
"brand new oil filter" There is where I would start.
Right. Carquest didn’t have the same 85551. Napa got me one they said swapped, a Napa # 1551. I’ll look online and see if I can check the numbers. But first I need to know for sure that the gravity flow into the filter is supposed to be about the same as the outlet side. Or what ratio is normal. I’m guessing the filter is slowing the flow by 90%. But if the pump is normally sucking maybe that filter is the right one. So that’s my questions. Is the filter normally reducing flow 90%, and does the pump suck fluid in
I think it’s air lock but won’t be able to bleed it until I get a 1” pipe T in the return port of the pump. I think the reason I’ve never had this problem before might be the cold weather. I’ve just done hydraulics in the summer. It’s a combination of things. I had the filler plug in the tank for one, causing air lock from above. and the hose goes uphill from filter to pump. I took every fitting apart and every hose off. When I opened the hose at the return I heard air coming out. But it’s not purging enough without a T.
KWentling
Veteran Member
- Joined
- Jun 22, 2002
- Messages
- 1,161
- Location
- Rozet, Wyoming
- Tractor
- Kubota BX22, Kubota ZD21, Kubota M7060
Pretty hard good advise with such little information, but I'll try. This is on 1957 Case tractor of unknown model. The pump might be a PTO pump? This pump draws form a reservoir on the loader? The valve was replaced for some reason? There should not be a filter between the reservoir and the pump suction. There ideally would be suction strainer in the tank that the suction hose attaches to. An alternative would be a Y strainer in the line. (If you truly have a hydraulic filter plumbed into the suction line, that line is probably collapsing.) The ball valve in that line would be fine. It would allow working the pump or line without draining the oil. The pressure line would go the the P port on the valve. The return line would go from the T port back to the reservoir and at some point between the valve and reservoir there would be a filter. Ideally the pump would be the lowest point of the system. The suction hose would all run down hill from the reservoir to the pump with no uphill humps to trap air. The fill cap on the reservoir should be vented. Hopefully your new valve has a pressure relief valve.
Of course it has a relief valve, it’s running a loader. The pump is almost the lowest point, it can’t be lower than the PTO shaft it’s on, and the tank is also the vertical post on the loader so it’s as high as it’s going to get, but it’s return port IS two inches lower than the pump and it works just fine. You call the return line a suction line accurately so why would the pump need to be lower than the tank return? The full cap should be vented as you say but it’s been unvented for the 25 years I’ve been using it.
Yes it’s a PTO pump, as I said, it’s a six spline gear pump so it’s a PTO pump, did you read my question?
What is your reason for not wanting a filter between the tank and the pump? It’s been there since I bought it 25 years ago. It’s not starving the pump and if it were, it wouldn’t hurt a thing, and I’d sure know about it.
My new Prince valve doesn’t have P or T ports. It’s got IN and OUT ports. It works great, I got it working today by cracking the pressure side of the pump for two seconds to purge the air and prime it.
BTW it wouldn’t make any sense to put the filter on the intake side of the tank because the tank is the only part that can’t be cleaned easily. It takes a pressure wash to clean it. It would probably be a good idea to add a second one there however.
KWentling
Veteran Member
- Joined
- Jun 22, 2002
- Messages
- 1,161
- Location
- Rozet, Wyoming
- Tractor
- Kubota BX22, Kubota ZD21, Kubota M7060
Wow. Sorry I tried to help. I stand by everything I posted and if you do a little research I think you'll find it's accurate. Not going to argue with you.
LD1
Epic Contributor
So is it fixed and working now? So I dont have to try to decipher exactly what is going on and whether the filter is on the suction line or return line.....because you contradict yourself several times about that.
oldnslo
Super Member
CMR
If possible Make sure the inlet line to the pump is full of oil before trying to operate the pump.
Also like LeeJohn stated make sure the filter element is correct. Several people have reported problems with after market filter elements in the suction line of pumps.
Kwentling is correct filter in the pump inlet is not best idea but a lot of systems are made that way.
If possible Make sure the inlet line to the pump is full of oil before trying to operate the pump.
Also like LeeJohn stated make sure the filter element is correct. Several people have reported problems with after market filter elements in the suction line of pumps.
Kwentling is correct filter in the pump inlet is not best idea but a lot of systems are made that way.