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Rebuilding a hydro pump from a D

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This is one awesome how-to Jeff, thanks for sharing. :text-coolphotos:

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Outstanding!!!! I have never messed with a hydro pump yet and have a couple to work on!! No I'm not so worried!!!!!! I vote to moved this to the most useful post area or have it pinned!!! Thanks Hodge71 (Jeff). :bow-blue: :handgestures-thumbupright:

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good thread here,does it work though,sure hope so after all the hard work

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Great thread for sure, as stated above, I have a couple that I dare to take apart now. Thanks

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Thanks for all the poisitive feedback guys. Keep the votes coming and maybe an admin will pin it for us so that it'll be here for all to benefit from. Thats why I did it. Alot of guys were nervous about tearing into one so Paul and I jumped in and now we all can see just how complicated they are. As long as you take your time amd label things its pretty straight forward. I would imagine that a hydro pump from a C is no different. They use a drive pully instead of and engine coupler and its a married system whereas the D uses a divorced system.

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Very informative post. Its amazing how similar the inside of that pump is to a Kubota B8200hst I had to repair a couple of years ago. :text-coolphotos::thumbs:

Matt :flags-texas:

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:bow-blue: Awesome post Jeff and I'm sure Paul's help was invaluable in what you achieved together. :thanks:

:thumbs: I've just given it my vote!

They are ORB also but damn were they tight. We needed to use an impact driver to break them loose. All thats inside is a ball and spring.

Was there any visible reason for this or is it just that they did them up that tight at the factory?

The reason I ask is that even with an impact driver I've failed to budge the reverse valve in mine.

Andy

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absolutely perfect Jeff ! :bow-blue:

same principles as rebuilding a multicyliner engine... everything marked and put back in the right place. No need for heavy handiness or gorilla tools :)

Hope it works well for you now.

mark

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Andy,

There was absolutely no reason for it to be that tight. This pump was definitely never opened up before. All fittings were tightened by an gorilla at the factory. We found no reason for it to be that tight, especially with and o-ring boss fitting. All sealing is done by the o-ring, not the trheads. We tightened all things but I know we didnt do it as tight as they were originally. I guess we shall see if it leaks. I have no doubt it will function perfectly.

Thanks Mark for the compliment.

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:bow-blue: Awesome post Jeff and I'm sure Paul's help was invaluable in what you achieved together. :thanks:

:thumbs: I've just given it my vote!

They are ORB also but damn were they tight. We needed to use an impact driver to break them loose. All thats inside is a ball and spring.

Was there any visible reason for this or is it just that they did them up that tight at the factory?

The reason I ask is that even with an impact driver I've failed to budge the reverse valve in mine.

Andy

Andy I do not know why they were so difficult. The day before i had opened up a junker pump (think training aid) and it was a real struggle to get the valves open. Had to soak with PB Blaster and wail away with the impact driver. Chewed up the slot as the bit was as a bit to small. Drag link sockets i had that would fit the slot were to fat to fit into the recess.

It was a real pleasure to work with Jeff on his pump.

Next up is to overhaul mine. I have to get my own 12 point 3/8" and 5/16" sockets. :)

The pump is actually easier to do than the hydro motor. With the motor you really need a press, and there is a high probability that the spring clip that holds the piston assembly on the shaft will break when you press the shaft out. (at least 2 of the 3 i have tried broke at least one finger on the clip).

Jeff made the pump housing gasket in about 5 minutes...They are also still available from Toro...as are the shims sets for the implement valve. So far I have looked at 2 pumps none had the shims....

A big thanks to Jeff for documenting our day. I had a great time.!!! :greetings-clapyellow:

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Just wondering if all the slippers are within .002" of each other and no more than .005" was taken off any particular slipper?

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Nice work Jeff. I would love to see this in a PDF format that I can download and save it for future reference. Now that I have a clear idea of what to expect inside one of the pumps, I will not be so skiddish about working on mine next time the need arises.

Kinda curious - how did water enter the closed system and cause the rust?

This definitely should be pinned.

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Nice job guys...I still hope I never have to go through the process though.....

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heres a pic of my broken retainer when i tore this 1975 c160 pump apart,there was other problems so i had to bite the bullet and take it to a shop,so you guys saved some serious cash doing it your self :thumbs:

006-3.jpg

007-3.jpg

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James I think water somehow got inside after it was taken off the tractor. There was absoluetly no water in the pump at the time of disassembly. It was perfectly dry inside but you could definitely see a water line where the cylinders below the line were rusted and the cylingders above the line were fine. It was only 3 pistons that would seize in the bores. I believe the cylinder has a machined finish and the pistons are chrome plated because there was absolutely no rust on them at all.

Tap,

All slippers were within spec.

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James I think water somehow got inside after it was taken off the tractor. There was absoluetly no water in the pump at the time of disassembly. It was perfectly dry inside but you could definitely see a water line where the cylinders below the line were rusted and the cylingders above the line were fine. It was only 3 pistons that would seize in the bores. I believe the cylinder has a machined finish and the pistons are chrome plated because there was absolutely no rust on them at all.

Tap,

All slippers were within spec.

I figured you checked that, Wasnt trying to be smart, just have seen pumps I've taken apart and slippers were polished on a grinder, 80 grit I think... :( or else I would ask and get this comment (WHAT!!!)(SLIPPERS???) :confusion-scratchheadblue:

Excellent Work

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Jeff and I were discussing the slippers the other day. I wonder, since they are NLA, and being made of simple brass, how hard could the be to make? If only I had the specs and a lathe. The pistons - well, they are much more difficult, but not impossible to replicate.

Kinda curious, anybody know the specs/dimensions of the slippers?

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Jeff and I were discussing the slippers the other day. I wonder, since they are NLA, and being made of simple brass, how hard could the be to make? If only I had the specs and a lathe. The pistons - well, they are much more difficult, but not impossible to replicate.

Kinda curious, anybody know the specs/dimensions of the slippers?

James I am not a machinist but the slippers would seem to be a bit complex. Then there is the issue of how crimp it on to the ball at the end of the piston.

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Paul. I certainly respect your opinion, you've helped me out immensely here with your knowledge.

I am no machinist either (but I'm a wannabe). I believe that while they may appear complex, they really aren't. The only critical dimension is the inside area that fits around the ball on the piston. The other parts of the slipper would have relatively wider tolerances. No doubt pressing it around the pistons would be a bit tricky, but sometimes the answers are easier than they appear. Also, I hear that brass is one of the easiest materials to machine.

I'm not sure if the slippers and pistons are pressed or crimped. If they are crimped, I think an arbor press with appropriate does would do the trick.

I may be overreaching, but I tend to do that. I learn a lot that way :)

Either way, I somehow see a lather in my future. Too bad all the good made in America ones are out of my price range I'll probably be stuck with a cheap import knockoff.

Too bad we don't have any current or former Sunstrand employees lurking around here. They would be an invaluable source of knowledge on NLA parts.

James

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To add some more info to Jeff’s very useful thread.

Turns out that there is some interchange possible between the hydro motor and hydro pump.

I opened up the hydro pump I hoped to rebuild but the slippers were too far gone. I have collected more motors than pumps and some of the motors had restorable slippers and valve plates. Problem was my first read of the manual focused on the fact the piston block assembly was not interchangeable between motor and pump.

However studying page 43 of the Sundstrand manual lead me to find that there is one-way compatibility. Motor piston blocks can be used on the pump also. (Older version pump piston blocks cannot be used on the motor).

Trying to figure out the difference took some time as one of my motors turned out to have the wrong piston block. (Note that was the motor that came on my D200 and the PO said it had been professionally over hauled. If I ever find the SOB in Connecticut it will not be pretty!)

Bottom line when you look down the splines inside the piston block if they are smooth (only one size/level) it is a pump only block. If you see (or feel) a slight step in the splines (about ½â€ from the bottom) it is a universal piston block. They did the extra machining to make clearance for the snap/clip that is in the motor shaft (but not on the pump shaft.)

You have to change out the 2 retaining washers and coil spring as they are unique to pump or motor. Finding a 15/16 OD washer to make the spring compressor took some time. (turns out 7/16†GR8 washer will work) The spirolock ring is the same in both cases… they come out easily but can be a bit of a pain to reinstall. (same design as the D series PTO)

Anyway I spent a couple hours cleaning and polishing the piston block valve plate and slippers from my old motor (that had a pump piston block in it) and hopefully the rebuilt pump will work well.

One more thing if you are D owner do not over-look pumps from C series. Other than the shaft the innards are interchangeable.

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Wow! This post just might cause me to overcome my fear of diving in to my pump on the D180. Thanks for taking the time and all the documentation!

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:) This is great information, My GT14 Trans is having problems and this has inspired me to give it a try. Thanks!

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:) This is great information, My GT14 Trans is having problems and this has inspired me to give it a try. Thanks!

By all means dive in, but remember GT14s had hydro gear not piston to piston sundstrands. The pump unit will be the same as discussed here. the motor end is completely different and according to WH was non-serviceable.

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