Where can hydraulic fluid go?

[ShawnAgne]

If you remember back to what seems like the never ending saga of issues I've had, 2 years ago when I installed the second piston and bypass block on the Cub I didn't adjust the relief pressure. This caused the hydraulic line to blow at the pump. I rebuilt the pump and it functions well. However last year when I was plowing snow somewhat and more so the 2 times I've mowed this year with it late summer and here recently I notice I always loose hydraulic fluid. Add it so it works, works while I'm using it, then when I go to use it next time not working. It is working when I use it, but then when I go to start it the next time, no bueno. The other issue I"ve been noticing here lately is that after I run the tractor for awhile (hydraulics aren't working) I get oil that is blowing out of the breather onto the mower deck, which I've read on here happens when there is to much oil in the oil pan.

So question is
1. Can hydraulic fluid make its way into the engine oil loop somehow?
2a. If the answer to #1 is yes, then where is this probably happening.
2b. If the answer to #1 is no, then where on the hydraulic block is the likely place it is leaking?

When I bought the tractor the previous owner had rebuilt it. As I side note when I do add fluid so it is working there is a higher pitch hum to it. I removed the line and pump and everything is attached and it is pumping.

[John *.?-!.* cub owner]

The answer is yes, it can and will leak around the o'ring in the front of the hydraulic pump and down into the crankcase.

[ShawnAgne]

Thanks John, and that explains why I'm blowing oil out the breather. So, what is the fix then? I got a rebuild kit and I rebuilt the pump, or so I thought in fall of 17. What should I check for, get, do, etc.?

Edit: As a side note I was looking at the pump rebuild kit on TM Tractor. I noticed there is a gasket that goes between the pump and frame. Don't remember where I got my kit from but I know I didn't get that gasket. Could that be the culprit? Just wondering if I should get a kit from TM and rebuild the rebuild since obviously something is not correct.

[Dale Finch]

The pump is apparently working. As John said, it is the o-ring (or seal) on the pump shaft, and it will need to be replace. You may need to remove any burrs or grooves made by the damaged o-ring. There are several posts about this. It is part #9, either the o-ring or seal, depending on which one you have. From the Hydraulics service manual:
http://farmallcub.com/rudi_cub/www.cleancomputes.com/Cub/Blue%20Ribbon%20Service%20Manuals/GSS-1024%20Touch%20Control/GSS-1024%20Touch%20Control.htm

[Crimson Tim]

Without the gasket between the pump and the engine, in might leak to the exterior. But if you have hydraulic fluid leaking into the engine oil, I don’t think there are really any other suspects other that O ring.

Reasons for premature failure?
Wrong O ring from kit installed? Install correct O ring.
Wrong size/type O ring provided in kit? Install correct O ring.
O ring got nicked/damaged somehow at installation? Install new, undamaged O ring, and look out for any sharp edges or burrs that might have caused damage.
Shaft where O ring rides is rough/worn? Smooth shaft with fine emery cloth or install speedy sleeve.

Some people have had good luck swapping in a modern lip seal or X-section seal in place of the O ring. Machining may or may not be necessary depending on the dimensions of the seal you end up with.

I have been running on a TM kit for several years without issue.

[inairam]

you can upgrade the o ring to a real oil seal.

The early pumps have a real shaft seal and the pumps on the numbered cub have a real shaft seal. The ones in the middle used an o ring.

I do not like an o ring used in a rotating shaft application.

viewtopic.php?f=1&t=40331&hilit=skf+seal

[Bob McCarty]

Have you checked the oil level on the dipstick? If it's high, the pump shaft seal is leaking, Hydraulic oil is not a good engine lubricant, so you'll want to also change the engine oil.

[Waif]

The buna ring has good reviews here and there. Believe that's what mine was replaced with.
No more oil blowing out the stack...
viewtopic.php?t=99760

[John *.?-!.* cub owner]

I assume you replaced the o-ring when you rebuilt the pump, but there is mos likely a groove in the shaft that frequently has sharp ridges in it running in the groove around the shaft. I frequently use an Abrasive Buff in a Dremel to smooth it going around the shaft with the buff, not lengthwise. Also this is a good place to use an X cross section o-ring.It gives 2 edges that run outside where the groove is. They also make a double X o-ring that has 4 more ridges, but I do not believe it would be any help in this case. I have been running a pump that had a shaft that would have normally beyond use, but I smoothed it and put an X 0-ring in and it has been in use for over 5 years with no problem.



https://www.mcmaster.com/o-rings
Note, this is the same size o-ring that is used on the shaft inside the distributor. The one problem is these are very difficult to get in the housings with out them being twisted. Also it does not hurt to use a sanding drum in a Dremel to make a slight taper on the end of the shaft to make it easier to get started through the 0ring. some oil on the shaft should be used too.

[Don McCombs]

When you go shopping for the shaft seal, you need a buna-N #112.

[ShawnAgne]

Ok clicked on the link, chose bune-n #112 and X o-ring, and only pack option is for 100?

Just want to make sure I"m looking at the correct thing.

Should I go ahead and get another rebuild kit from TM tractor also since I don't have the gasket from the pump to the motor?

[Glen]

Hi,
Hard to know if everything from the kit you put in will still be good after taking it apart again.

TM Tractor has the gaskets separately also.

http://www.tmtractor.com/new/hy/428fp.htm

http://www.tmtractor.com/new/hy/310fp.htm

[Don McCombs]

Ok clicked on the link, chose bune-n #112 and X o-ring, and only pack option is for 100?

Just want to make sure I"m looking at the correct thing.

Should I go ahead and get another rebuild kit from TM tractor also since I don't have the gasket from the pump to the motor?

If you have a real hardware store locally, you may be able to find the correct o-ring in the round cross-section in a more reasonable quantity.

[John *.?-!.* cub owner]

Yes, round o-rings in the correct size are readily available, but they ride in the smae groove as the original and frequently do not seal well. The lips of the X o-rings ride on the shaft outside the groove and seal better. A large hardware store may stock the X 0-rings, but that will probably br hard to fnd.

[ShawnAgne]

Well 100 of them it is. If you need any I know a guy who has some....