HY-2/3 Reseal

[adsm08 2,022]

I haven't been able to find any sort of instructional on this beyond the exploded parts diagram, so here goes. I got started re-sealing my HY2 pump (I'm told an HY3 is very similar on the 855 today, took lots of pictures, so now I'm going to do a write up. It seems like a simple enough process.

 

Here is the unit, already off the tractor. That was easy enough, remove the two hydraulic lines, remove the two bolts holding the belt cover on, the set screw that holds the pulley on, and the two bolts that hold the pump on. None of that is  pictured because I don't know how the specifics may change from one model to another.

 

Here is the pump:

 

Step one (after removal) is to remove the nut at the left hand side of the picture. Once the nut is off the reservoir cannister can be removed. Mine was glued on, so I had to mount the pump head in the vice and bang on it a bit before screwing it off. After getting it off and cleaning it a bit I believe it should be able to just slide on and off. 

 

Pulley/control lever end:

 

 

The control lever is out of mine, but this can probably be done without removing it. The set screw on my pulley won't stay put, and so the pulley walks around some times. You can see where it has been rubbing the control valve hub.

 

 

This is the left hand (relative to the tractor) and of the reservoir. You can see the sealing washer that is glued to the end of it. In the seal kit from wheelhorsepartsandmore.com, the replacement is a cupped silver washer with the convex side rubberized. Mine was also silicone in, so I had to knock a little screwdriver under the edge and pry it off.

 

 

Cleaned it out as it had a fine metallic film inside, similar to what you find in the pan of an automatic transmission when replacing the filter.

 

Here is the pump head, still mounted in the vice:

 

 

The shaft the nut threads onto is in the center and needs to be removed. It turned out easily by hand.

 

 

The reservoir seal is a square-cut lipped O-ring that sits in a groove at the outside of the head.

 

Look at the 6:00 position of this picture:

 

 

I took a 45* angle pick, slipped it, and just popped the seal out.

 

Here you can see the back face of my pump is messed up a bit. I should probably look at replacing the spring, but that's going to have to wait, as I should probably also try to devise a way to keep the spring retained better since it is the return for the lever. It is not staying put, and so I need to return the lever to its neutral position manually each time.

 

 

 

Remove the 6 screws around the heart-shaped gear cover and bam:

 

 

Gears.

 

Gears and shaft come out by just pulling gently. You may need to push inward on the pulley end of the shaft to get it started.

 

 

 

 

 

The return spring is retained into the control valve by a roll pin that runs perpendicular to the channel.

 

 

Roll pin comes out pretty easy, with the right tool. That's an old Craftsman straight pick that I cut the end off of. It happens to be just perfect for most roll pins.

 

 

Next there is a second roll pin at a 45 degree angle that is in a blind hole. A pair of side cutters will remove it, but be careful not to cut it.

 

 

Grab it firmly, but gently, and use a lever action to pull the pin outward.

 

Next flip the pump head over and remove this snap ring. A small screwdriver inserted into the wedged area will get it out of the groove, and then it can be removed by hand.

 

 

 

 

 

Then the control valve comes out. I had to encourage it gently with a plastic-faced hammer. I also did not remove it the whole way.

 

 

And here is the sealing ring for the valve:

 

 

 

Stick your 45* pick under it, and pop it out just like the reservoir seal.

 

 

To reinstall it put your pick through it, lay them both over the top of the valve, and just push/roll it in gently. 

 

 

Reinstall the snap ring before dropping the valve back in. The snap ring keeps it from going in too far, the return spring keeps it from falling out. IF YOU HAVE NOT INSTALLED THE NEW SHAFT SEAL DO NOT REINSTALL CONTROL VAVLE SPRING OR THE ROLL PINS AT THIS TIME!!!!

 

 

In the foreground is the shaft seal, which is what prompted me to do it, and is probably the most common leak point. It should be

 

 

To remove it set the control valve back in to its installed depth and use it as a fulcrum. Set a flat blade screwdriver under the outer lip of the seal, and pry gently.

 

 

The seal should pop out easily.

 

Old and new seals together. The new one is redesigned so it should sit on a different spot on the shaft and thus seal better.

 

Proper seal installation is important as there is a fluid passage right there, presumably to keep the shaft lubed where it goes through about a 1/2 inch of other metal. Improper seal install will cause a bad leak here.

 

This is as far as I got tonight because I did not heed my own advice and had the control valve and spring fully installed when I tried to put the new shaft seal in place. Trying to hold everything at funky angles cause my seal driver to move, and get the new shaft seal off center/level and I buggered it up pretty bad. I've already talked to Joette at Wheelhorsepartsandmore, and they are going to get another one out to me. Hopefully I'll have the rest of the job, and the write up, done by the weekend.

 

 

 

 

 

 

 

 

 

[ebinmaine 67,281]

I don't have any hydros or hydraulic pumps of any kind but that looks like a nice write-up so far.

 

Lowell and Joette... Good folks!

 

[adsm08 2,022]

35 minutes ago, ebinmaine said:

I don't have any hydros or hydraulic pumps of any kind but that looks like a nice write-up so far.

 

Lowell and Joette... Good folks!

 

 

 

Thanks. I frequent another gearhead forum where user-written instructionals like this are one of the keystones of the site, and I have written a few.

 

Joette seemed nice. When I was talking to her I had the feeling that if I had been there in person, rather than on the phone, I'd have been offer some sort of pie.

[953 nut 55,088]

You have a very well documented thread going there.               Here is an old thread that may be helpful too.

 

Edited May 8, 2019 by 953 nut

[Mike'sHorseBarn 2,989]

Nice thread! I redid the HY-2 on my 753 last summer. First pump I ever dove into and it went pretty well. You are fortunate that the neutral return spring wasn't broken! I have an HY pump (not sure of the number) on a cub cadet 104 that i need to dig into next, but the return spring setup is a little different.

[adsm08 2,022]

Installment 2:

 

So I talked to Joette today, their son has been having some issues, possibly related to his accident, and so she has been tied up, and it delayed getting the new shaft seal out. OK, no big deal, I still have Juan to take care of the grass with.

 

Since I had some extra down time though I decided to tackle the damaged return spring holes. First I consulted with my weldor about possibly building the area up and re-drilling, or just tacking a spring into the holes. He had concerns about the heat warping the head face, and the control valve bore. Frank's a smart guy and when he talks I listen. We also both have a knack to taking weak designs and improving them, so I sent him a butt-load of pictures to look at, and then we put our heads together, and decided to design a repair bushing that would stand proud of the pump face and give the spring more to grab on to. We agreed on a basic functional design, and then I was off to the workshop to see what I had laying around that I could make it out of.

 

The micrometer said that the egged out hole was just under 1/8 inch.

 

Now it was also egg-shaped, so I was going to have to make it a little bigger to make it be round again anyway, so I started looking on my hook wall next to the compressor, and in my scraps drawer, and scrap pile. While digging I found that the spring fits the inside of a piece of 3/16th brake line almost like it was made to go in there. If I didn't know why they made that stuff I'd say that the spring was actually made out of the bit they pushed out of the middle when making the line.

 

So I got the micrometer back out and started measuring. The OD of my 3/16 drill bit is 4.30mm at the base. The OD of 3/16 inch Nicopp line is 4.69mm. Not quite right, but close enough!

 

So I stuffed the other holes in the area with rags, dropped a small donut magnet around my bit to catch shaving, and I made the holes bigger.

 

 

When I test fit off the whole roll the brake line would not fit, obviously. Its about 4/10 of a mm too big. So I chamfered the end, and I was able to get it started.

 

 

I cut off two sections of line just about 1/4 inch long, and drilled the two spring holes out to 3/16th inch, stopping just above the bottom of the original hole.

 

The hole on the left was a bit of a loose fit, it had to be tapped in, but the bushing would come back out too easy for my taste, ie: It could come back out, so I dabbed a bit of red thread-locker on the end, and tapped it back in. That was the hole that was really buggered, and the hole may have still not been perfectly round. The bushing on the right stayed put nice and tight, and I could lift the pump head by it, so I didn't glue it, because it went in for a test fit and wouldn't come back out.

 

 

Ta-da!

 

 

I left them long enough to stand proud of the pump face for extra inserted depth and support, as not enough inserted depth is probably what allowed the original failure to occur in the first place.

[adsm08 2,022]

Pt 2:

 

New seal kit and spring came in today. As I was wondering, the new spring is longer:

 

https://i.imgur.com/vynP7fO.jpg[/img]

 

So despite being very careful this shaft seal would not sit centered and wanted to walk and deform as well. Since I didn't have any more time (or money really) to throw at this since I sold the JD this morning, I called Lowell. He said he has had the best luck starting them with a socket that is just a tiny bit bigger than the seal, enough to sit in the mouth taper, not enough to drop in. I tried that and didn't have any luck, the seal wouldn't go in, and was starting to deform again, so out comes the eye-crometer and I decided to experiment with something unconventional. I didn't really have anything to loose at this point.

 

There is a lube hole that can't be blocked, probably to keep the pulley shaft oiled so it doesn't burn up the seal. The new seal was tapered at the outer side, both at the outer edge, and the rubber boot going inward, so I installed it backwards. I found a washer that the boot fit inside, but sat over the metal ring:

 

https://i.imgur.com/3uxQ4WJ.jpg[/img]

 

And I drove her in.

 

https://i.imgur.com/VvIcxzM.jpg[/img]

 

The sealing surface is riding close to the flat land for the pulley's set screw, but not in it, and actually outboard of the spot the old seal rode. With the ring sitting flush it also does not close off that lube passage.

 

Then I RTV'd the outer area that is supposed to be inside to protect the spring and rubber from the elements as best I could.

 

 

After that, I dropped the new reservoir gasket into the channel, applied some RTV to the back of the reservoir washer, and put it all back together the way it came apart, and back on the tractor.

 

Filling it was interesting, I didn't have a funnel nearly small enough, so I drilled a hole in the lid of a water bottle, cut the bottom off, and kept the flow running into the upper plug hole, until it started coming out the lower hole.

 

Got the belt on, fired it up, deck goes up and down, no leaks yet. We will see how long this holds up. Hopefully if it doesn't last long term it lasts long enough for Lowell to get that shaft seal listed by itself. He told me it was on the to-do list, he just never seems to get around to it.

 

Personally I think this would all go much simpler if the seal was manufactured to have a straight edge, or one that was tapered in at the bottom of the ring. It looks like it tapers out and flares a hair at the bottom, which would certainly cause the issues I had.

Edited May 16, 2019 by adsm08