Hydraulic pump rebuild

Mon Aug 30, 2010 8:23 am

Hey guys,

I was getting hydraulic fluid in my crankcase oil and ordered the rebuild kit from TM. This morning I pulled the pump and put in all the new parts. I didn't experience any issues with the rebuild. When I reinstalled the pump I topped off the reservoir and started the tractor. I got no reaction from the hydraulic system, so I went ahead and ran the lever through its cycle a number of times. Nothing. I then came to the PC and did a search on this problem and discovered that if I loosen the bolts at the back of the pump, that should "burp" the system and I should be able to have hydraulic nirvana. No reaction in the system. I then loosened the three bolts that attach the hydraulic lines at the touch control box. Virtually no fluid came out of the touch control box. I don't know a whole lot about hyraulics, but would think that enough fluid would come out of the reservoir in order to prime the pump. I don't want to run the tractor a whole lot with no fluid in the pump either. By the way, the system was working just fine before I started "fixing" it. Any help is certainly appreciated. :?: :?: :?:

Tom

Re: Hydraulic pump rebuild

Mon Aug 30, 2010 8:50 am

When you loosened the two bolts on the manifold at the pump, did you wait long enough for the oil to reach the manifold and start leaking out before you tightened everything back up ?

Re: Hydraulic pump rebuild

Mon Aug 30, 2010 8:54 am

The bolts were loose and the manifold had daylight between it and the pump body for about 30 minutes. No oil (not a drop) came out of the loosened manifold.

Re: Hydraulic pump rebuild

Mon Aug 30, 2010 9:04 am

Tom:

I imagine you found the GSS-1024 Touch Control manual :?: Sounds like there is a blockage somewhere or there is simply not enough Hy-Tran in the system. No pro on hydraulics, still learning but it kinda makes sense to me.

Re: Hydraulic pump rebuild

Mon Aug 30, 2010 9:18 am

Rudi,

Yes, I checked the Touch Control Manual, but didn't see a smoking gun. The reservoir is topped off and I can actually see the level when I look into the filler hole. The blockage theory is interesting, but the system was working perfectly before I "fixed" it. Should the touch control box drain itself dry when I pull the lines off? Earlier this morning, when I started the job, I only got about a half cup (4 ounces?) out of the reservoir.

Tom

Re: Hydraulic pump rebuild

Mon Aug 30, 2010 9:54 am

First thought, make sure the reservoir is really full. There is a cast deck just inside the filler hole. Make sure you aren't interpreting some oil on top of it as being full when it really isn't. If that isn't the answer, try pulling the 2 bolts that hold the manifold to the pump again and applying a little air pressure to the filler opening. See if that pushed some oil out at the pump.

Re: Hydraulic pump rebuild

Mon Aug 30, 2010 10:35 am

Tom:

I think I found the smoking gun...

Tom wrote:Rudi,
Earlier this morning, when I started the job, I only got about a half cup (4 ounces?) out of the reservoir.
Tom


Here is the table from the Owner's Manual

Image

Now checking with my better half, a pint is 2 cups which means you should have 7 cups of Hy-Tran in your reservoir. 1/4 cup is severely below full and is probably the reason why you do not have any fluid at the pump. Don't run the engine without hydraulic fluid at the pump... you may end up redoing the job again :roll: :(

Re: Hydraulic pump rebuild

Mon Aug 30, 2010 10:44 am

Rudi wrote:Tom:

I think I found the smoking gun...

Tom wrote:Rudi,
Earlier this morning, when I started the job, I only got about a half cup (4 ounces?) out of the reservoir.
Tom


Here is the table from the Owner's Manual

Image

Now checking with my better half, a pint is 2 cups which means you should have 7 cups of Hy-Tran in your reservoir. 1/4 cup is severely below full and is probably the reason why you do not have any fluid at the pump. Don't run the engine without hydraulic fluid at the pump... you may end up redoing the job again :roll: :(

Rudi,

He only got a half cup of fluid before he rebuilt the pump. That was to be expected, because the balance was in the crankcase.

Re: Hydraulic pump rebuild

Tue Aug 31, 2010 9:47 am

:brainfart:

Tom:

How much did you put in? Did you measure or use the TLAR method :?:

Re: Hydraulic pump rebuild

Tue Aug 31, 2010 9:07 pm

Rudi wrote:.... Don't run the engine without hydraulic fluid at the pump... you may end up redoing the job again :roll: :(
Been there, done that, only ran for about 20 seconds before I realized what i had done. too late, I had a the older style with seal rather than o ring, but seal was already toast.

Re: Hydraulic pump rebuild

Wed Sep 01, 2010 8:03 am

Well, I thought that I would lay off the cub for a day and start at it again this morning. Just to try it one more time before I tore into the system, I started the cub. The hydraulics work!!! I was so happy that I did a back flip off the roof of the house. NOT. But it was certainly a most pleasant surprise. I guess the fluid just needed a little time to be coaxed out of the reservoir. Thank you everyone for your help. See you at the Cubarama. :{_}: :{_}: :{_}:

Tom

Re: Hydraulic pump rebuild

Wed Sep 01, 2010 8:13 am

Tom,

I think you probably just had a bubble in the system. A few more cycles of the control would probably have gotten the job done. Glad you got it working. Check the fluid level again, now that the bubble is in the reservoir.

Re: Hydraulic pump rebuild

Wed Sep 01, 2010 8:29 am

Tom:

Agree with Don, air in the system. I have had to redo the gaskets on Ellie's TC Manifold a number of times cause I kept blowing them out. Needed a Pressure Relief Valve..... :oops: :roll: Each time the gasket blew, most of the Hy-Tran blew out with it.. (yup, got expensive :lol: ). Until I got used to it, it used to bother me when the TC wouldn't lift properly right away. Most of the time it was because there was either not enough Hy-Tran or because there was air in the system. I very seldom measure what I need -- (very bad habit I hope to fix in time), I just add until it works properly, then I bleed the system and add as needed until the TC operates smoothly.

I would also follow Don's suggestion that you continue to check the Hy-Tran level as you cycle the system. Top off as needed.

Glad you got it fixed :D

Re: Hydraulic pump rebuild

Mon Aug 12, 2013 1:05 pm

Sorry to revive an old post, but I was having the same problem and found a really simple fix. when you have the bolts loose at the pump, Just pull the fill plug off and you'll hear it "burp". 2 seconds later the fluid will reach the pump and you can re-tighten everything!

Re: Hydraulic pump rebuild

Mon Aug 12, 2013 7:46 pm

Old revival is fine with those of us currently working on our Cub. I'm currently rebuilding my TC this week after I pick up my parts tomorrow from Case. I like the "burb" hint. Thanks