Hydraulic Problem after Installing Pump Kit

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jsr348
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Hydraulic Problem after Installing Pump Kit

Postby jsr348 » Sat Jan 13, 2018 11:08 pm

Bought a '61 Cub Thanksgiving weekend and have enjoyed working on it--until today. I suspected that hydraulic fluid was getting into the oil since oil level was above the full mark and the hydraulic unit needed fluid to top it off. Otherwise the hydraulics has worked fine. To be safe I installed a pump rebuild kit. I did not touch the hydraulic unit. I took care to clean and put everything back the way it came apart. However, the hydraulics don't work at all now. I loosened the lines and fluid ran out. I took the pump out and it turns and burps out fluid if I pour fluid into and turn gear. Re-assembled and topped off fluid again-- still no hydraulics. I moved the hand actuator a bunch of times and filled with the arm back (piston in). I used Tractor Supply fluid that lists as Hy-tran compatible. It is cold out in the barn (7 degrees) I am hoping the fluid is thick due to the cold and Hydraulics will work in the morning. Otherwise, anyone have any ideas?

Bob McCarty
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Re: Hydraulic Problem after Installing Pump Kit

Postby Bob McCarty » Sat Jan 13, 2018 11:18 pm

I would suspect that you have air in the lines and the low temp is preventing the cycling from removing the air.
"We don't need to think more,
we need to think differently."
-Albert Einstein

jsr348
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Zip Code: 43015

Re: Hydraulic Problem after Installing Pump Kit

Postby jsr348 » Sun Jan 14, 2018 12:05 pm

Tried hydraulics this morning and still not working. Pulled pump for the third time. Everything looks good. It has fluid inside so not worried about running it dry. I notice that the touch control seems to move more freely than when it was working. I moved the cub into the garage attached to the house. It is above freezing in there. Also noticed chunks of ice in the drain pan when I was cleaning up. I had planning on rebuilding the hydraulic unit in the spring. Looks like I need to get that done sooner. It was a little sluggish when it did work. Time to build a fire in the wood stove and start reading up on the hydraulic system in the service manual this afternoon.

Bob McCarty
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Re: Hydraulic Problem after Installing Pump Kit

Postby Bob McCarty » Sun Jan 14, 2018 12:13 pm

Did your pump require the tiny pin seal, and if so, are you sure it was installed?
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we need to think differently."
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Re: Hydraulic Problem after Installing Pump Kit

Postby Eugene » Sun Jan 14, 2018 12:14 pm

Couple of things.

The brass plate just under the pump's front cover has to be placed so that the small tabs face the front cover. That brass plate is what builds up hydraulic pressure within the pump. Facing the wrong way and the pump will pump fluid but not build up pressure.

Some pumps have a small plug that fits in the center. That plug has to be there.

I see Bob has posted about the tiny pin seal, the plug I mentioned.
I have an excuse. CRS.

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Re: Hydraulic Problem after Installing Pump Kit

Postby radioguy41 » Sun Jan 14, 2018 5:08 pm

The pin seal is #8 in the illustration.

cub_hyd_pump.jpg


1958 Farmall Loboy-034s.jpg
Circle of Safety Image ImageImage

jsr348
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Re: Hydraulic Problem after Installing Pump Kit

Postby jsr348 » Sun Jan 14, 2018 5:47 pm

Pin seal is installed.

Eugene - I had the tangs of the flat spring pointed toward the bushings. I tore it down and turned them around (towards the front). Still nothing.

I am confident that the pump is okay. I will let it set a day or two and see if it works. If not, I will get into the touch control next. The fluid that I first drained out was ugly.

Thanks for the suggestions.

jsr348
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Re: Hydraulic Problem after Installing Pump Kit

Postby jsr348 » Tue Jan 16, 2018 6:32 pm

Update!

I resigned myself to getting into the touch control unit itself. I pulled the snow plow link off of the arm and decided to check the unit one last time with no load. The arm moves! No jerking - smooth, strong, and fast one way but slow, and weak the other way. I worked the control a bunch of times and no improvement - fast forward and slow back. I can stop the arm by pushing back on it one way, but it is too strong to stop the the other way.

Fluid level seems to be correct. Looking into the filler, I can see the fluid come up and down as I work the actuator.

Is it time to get into the control unit?

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Re: Hydraulic Problem after Installing Pump Kit

Postby tst » Tue Jan 16, 2018 8:35 pm

before taking the system apart you should put a pressure gauge in the system, it will tell you if the pump is working or not so you will know which part is the problem

jsr348
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Re: Hydraulic Problem after Installing Pump Kit

Postby jsr348 » Tue Jan 16, 2018 9:02 pm

Any recommendations on where I can get a gauge?

jsr348
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Re: Hydraulic Problem after Installing Pump Kit

Postby jsr348 » Sat Feb 03, 2018 9:42 pm

Problem solved!
I bought a gauge (Amazon) as recommended. There was no pressure at all even though fluid was flowing. I rebuilt the touch control hoping to find a problem there. Other than a hole in the screen, everything looked okay and still no hydraulics.
I bought a new after market pump. It felt awfully stiff out of the box. Filled it with fluid on the bench and turned it. Hard to turn, but felt smooth. On installation, the rear bolt head was so close to the body that even a thin wall socket would not fit. Tightened it with an open-end wrench on end.Tightening with a screwdriver through the closed end of the wrench. Will look for a allen head bolt if it starts to leak oil. The good news is the pump works. I had to work out a little bit of air.
While the hydraulic lines were off, I adjusted the valves. That took care of an occasional miss at low rpms. All valves were tight (~.06). Adjusted them to .15"
It has been 1 step forward and 2 back, but this old cub is starting to sound and run nice!

Thanks for the replies to my post and all the great advice, overall, on this site!


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