[Bill56]

How do I test a hydraulic pump system to see if it is putting out any pressure?
The pump is on an end loader. When I pull a lever, there is no movement of the cylinders or any flexing of the hoses. I removed the pump, and when I rotate it by hand, it does push out some fluid. If anyone has any ideas, please let me know.

 

[Caseguytoo]

If the reservoir is full of oil and the loader cylinders won't move, then most likely, the pump is toast.

What you have is called an "open center" hydraulic system. Oil is gravity fed to the inlet of the hydraulic pump and then pushed by the pump to the loader control valve. From there it returns to the reservior to be pumped again. The only time the pump does any serious work is when one of the two levers is pushed or pulled. The flow of oil is then diverted to one end of the cylinder/s or the other.

In order to test your system for the max pressure it will put out, you need a glycerin-filled pressure gauge capable of reading at least 3000 PSI. You also need some hydraulic fittings and a high pressure hydraulic hose to connect the guage to your system. You need a Tee fitting that will you to insert it right at the point where the high pressure hose coming from the pump to the loader valve screws on to the loader valve. Remove that high pressure hose from the loader valve and screw on end of the Tee fitting onto the valve and then screw the hose onto the other end of the Tee fitting. The third opening on the Tee fitting connects to the high-pressure guage.

In order to test for pressure, start the tractor after installing the above items and checking that you tightened all fittings. With the tractor running at half throttle, pull the bucket control lever backward and hold it in that position. If you don't see the pressure increase on the guage, to at least 500 pounds, then the pump is likely weak and needs to be replaced.

 

[TUDOR]

If the oil is flowing and Caseguytoo's tests show no pressure, check the relief valve. They rarely fail, but when they do, there will be no system pressure to speak of. A little dirt in the relief will also cause a no pressure situation.

Is this loader a new set up or has it been working prior to this problem? If new, check the pump rotation direction, if used, check for mechanical damage to the pump shaft, inside and out. A sheared key or worn interference fit will move oil at the speed you can generate by hand, but will slip at engine speed.

One more thought. I know it's basic, but we've all been caught at it at least once. How's the oil level and filter?

Good luck.

Bob

 

[Bill56]

Thanks for the help guys. :thanku:

The loader is mounted on my Bolen's 1050. It is a factory loader, made by Danco. It's a very "tired" machine, that's been in storage and, up until yesterday, hadn't been run for almost 30 years. The hydraulics were not working good at the time it was put into storage. I suspect that the pump may be "toasted", and may need to be replaced, I don't have a guage, or know of anyone that has one to borrow. I'm not sure if it would be worth the money to buy one. My budget for fixing this is about zero, so maybe it would be better to just go ahead and look for a replacement pump of some sort, but I'll try to check, all the things I can, on this pump first.
The intake side of the pump, directly mounted to a small tank, is positioned at the front of the machine, just in front of the grill. The pump (Cessna) is driven from the front pto. It's a nice looking set up. I'd like to at least keep the pump positioned where it's at. Maybe putting a replacement pump at the front, and moving the tank to another location would be the cheapest way to go. There is no filter on the system, so moving the tank and installing a filter, somewhere, would probably be a good idea. It's not designed to be a quick acting loader, like a big tractor, so I don't think it would need too costly of a pump. Maybe even a power steering pump would work. Any thoughts on that idea?

 

[Tractor-Holic]

A P/s pump might work,but would probably be slow and lack the needed GPM to make it work efficiently...I have seen lots of Cesna pumps on the www.surpluscenter.com website for sale,perhaps they might have one close to yours that would work for a reasonable price,or another brand that'll interchange..

sualy the pump whines like a siren when it gets worn and too much leakage occours in it..

 

[Caseguytoo]

Tudor makes a good point about the relief valve. It should be located in the loader control valve. Photos would be a huge help here.

The guage is a twenty dollar item here http://tinyurl.com/ku8l8m and can be found for as little as twelve at some places.

Item 4020 is overkill for your tractor but it will certainly work. http://tinyurl.com/nt8kuv

If you click on any one of the three valves shown at the top of this page http://tinyurl.com/nvv2mx and then enlarge the photo, you can see the relief valve on the end closest to you and the adjustment/access to the relief next to the control handles. The relief consists of a concave seat with a steel ball bearing sitting over the hole drilled in that concave seat. There is a coil spring that presses the ball bearing against this seat to close the hole off. If the oil pressure in the system rises higher than the pressure from the spring, then the ball will lift off the seat and allow the oil to escape back to the reservoir.

If a piece of junk gets stuck between the ball and the seat, then the hole will remain open. If the spring breaks and then collapses into itself, then the ball won't stop the flow. Rule out the relief valve first.

It it's ok, then remove the pump and take it to a hydraulics shop. They can run the number and tell you if parts are available. Belt driven pumps use special bearings to support the side loading that a pump that is coupled straight on to a shaft never encounters. In other words, any new pump you contemplate buying, must have bearings capable of handling the side loading stresses from belt drive.

 

[Bill56]

I will look at the Surplus Center and Northern sites. I see that Northern has a store that is a couple hours from me. I have some relatives that direction too, so maybe I can make the trip and save some shipping.
I emailed a Bolens repair guy, that was listed on the MTF Bolens forum. He said that the pump should not exceed more than 8gpm. I think Northern has a 6gpm pump for around $129.00. My Cessna pump is direct drive - no belts - so that isn't something I have to worry about. The pump on my machine does have a longer shaft than anything I've seen listed, but I think that would be a somewhat easy problem to overcome.
I have a busy week/weekend coming up, so I may not be able to do anything more till next week. I managed to get the engine started. yesterday, but wasn't able to run it long enough to investigate anything about the pump...gas line had rotted through. I'll have to get that fixed first.
Like I said, this tractor is in need of a lot of help. I had to go buy a can of tire "goo" just so I could get it moved to the front of the garage. Steering has some issues, too, so there's plenty of work to do.
I'll try to get some pictures posted so you can see what I'm talking about.

Thanks again, to all of you, for the help.

 

[C2H8O]

This information helped me, too. I have a bolens with hydromatic drive, and the lift cylinder seemed weak. Now I know where the relief valve might be.

Are you sure the pressure range would reach to 5000 psi? I do not know, I too am new to the Bolens.

 

[Caseguytoo]

Doug,
When testing hydraulic systems to see what pressure is there, you can't take any chances on have a guage that won't handle the pressure.

Realistically, your Bolens with a hydrostatic drive will have what's called a "charge pump" that is part and parcel with the whole hydro unit. That charge pump serves a purpose for the hydro but it can also be tapped into to provide some modest hydraulic power for cylinders.

At best, your pump would put out perhaps 3 or 4 GPM and be able to develop 1000 PSI tops. I suggest that you go to the Bolens site here at MTF and provide that list with the model and serial number of your tractor. They can probably tell you which make and model hydro is in your unit and then the specs can often be found on the manufacturer's website.

In other words, you need to know what SHOULD be there in the way of pressure in order to make a test. Remember this..... max pressure in a hydraulic system is created when a cylinder has travelled as far as it will go and you still hold the lever in the ON position. Go buy a gauge that reads 3000 PSI and it will cover almost all the tractors you are likely to own. Systems in the 4000 PSI range are not very common compared to systems that max out at 2200 PSI.

 

[Bill56]

After I wrote my last post, I got to wondering why a manufacturer would make such a nice looking loader, and not put a filter on it. Then I remebered something from a place I used to work at. They had some machines there, that had the filters inside the hydraulic tank.
I took some time, removed the cover off my tank, and sure enough, there was a filter. Not much of one. Just a micro screen about the size of a man's thumb, but it was doing it's job.....it was plugged almost solid. Maybe I'll get lucky and that will be the problem.
Any advice on cleaning it? I doubt if I could find a replacement filter. I washed it in detergent. Then boiled it in water for a while and then washed it some more. It seems a lot cleaner, than it was, but I don't know if it will be good enough. I guess I could pour some oil in it and see how it runs through.
The bottom of the tank was a gooey mess too. There's just a pipe plug, with a small hole for a breather. I'm guessing, since the tank is down in front, right behind the bucket, that I better figure out how to install a filtered cap. I know they make a simple breather that I could just screw into the tank.

 

[Caseguytoo]

I think you've found the problem BUT....if the pump has been starved of oil for a long time, then essentially.... it has been allowed to run in an almost "dry" state and that does not bode well for any pump. I would take the tank and screen to a place that has a heated tank filled with caustic soda and ask them to cook it for you. Engine rebuilders have such tanks as do automotive machine shops that specialize in doing valve jobs.

I would also carefully dismantle the pump. Do this on a clean bench and spread a large rag on the bench to catch anything that might fall from the pump when you open it up. Look for accumulations of metal filings and heavy scoring in the end plates. Check the gears for any sign of metal galling.

If you are unsure about what you see, then take the dismantled pump to a local hydraulics shop for a 1 minute inspection. Their experienced eyes will know just how good or bad this pump is. Depending upon what you find, you might want to remove all of the hydraulic lines and wash them out with solvent. The rod end of the loader cylinders should be removed from loader so you can pull the rod/piston in and out to remove all of the old oil.

This is your opportunity to really clean this hydraulic system up. If you are really, really lucky.... the pump will still have some good life in it but that life can be shortened if you leave contaminated oil in the system to circulate. As for oil, you can use ATF or any universal hydraulic fluid. My choice would be the ATF along with installing a true oil filter on the return line to properly clean the oil instead of just catching the rocks.

 

[Bill56]

It may be a few days, before I can get to it. I'll take a look at the pump and get everything cleaned and flushed. Thanks for the help.

 

[TUDOR]

Bill56, I have a small Danco loader that I bought about 30 years ago. It had a small (about 2 or 3 quart) rectangular reservoir with a bolt on top, 2 one way cylinders for the arms, a 2-way cylinder for the bucket, a 2-spool-with-relief valve set with 1/2" npt ports and a Cessna 1.4 gpm @ 1800rpm pump. I was told that it came off of a 10hp Bolens. I've used the hydraulic parts for other projects, but thought the specs on the pump might help if the rest of the info sounds familiar.

Older GM power steering pumps put out about 1 1/2gpm @1200-1450psi. They have a built in flow control/relief valve to keep the flow rate down in high rev situations. The flow control can be 'adjusted' with a properly applied drill bit.

Bob

 

[Bill56]

BOB:

Yes, I think the loader you described must me the same one I have.
Thanks for sharing the information. That will be a big help. I was guessing that the Cessna pump was a low output. I can remember that the cylinder movements, on this loader, weren't all that fast. If, for whatever reason, I can't get the Cessna pump to work, I may go with trying to "rig up" a power steering pump. I have a friend that made a feed wagon that had hydraulics for positioning the auger. He used a power steering pump that drove off the fan belt of an old Oliver tractor. Seemed to work just fine. We used it a lot.

Thanks again for the help, BILL