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dave45056

Vickers Charge Pump

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dave45056
I am having troube getting my Simplicity 3415h going. When I say going I mean moving... it runs fine. The hoses are fine and the filter is a new wix unit. When I bought the tractor the hydro worked but was leaky and noisy. I replaced the ball bearings, seals and o-rings in the hydro unit and re-installed it in the tractor. After bleeding it I tried it out. It didn't work. I found plenty of flow on the return line. I decided to take it out again and take a look inside the pump. I found the charge pump was no longer in time (dots not lined up maybe 180 degrees out). So I lined them up and re-assembled everything. After filling it up with Dextron and bleeding it, it worked... but slowly. So now I am thinking the charge pump is still not lined up but is close. Does that make sense? I am also wondering if there is a trick to installing the charge pump. On the Vickers its inside the transfer blocks. It has to be done with the dots on teh gears facing down, and the shaft has to be installed afterwards. Its easy to get it wrong. Any help is appreciated.

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dave45056
Something else which would help... In my repair manual there is a great troubleshooting section... for Sunstrand. Troubleshooting for the Vickers is almost nil. Does anyone know where I can check charge pump pressure?

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dave45056
I'm getting pretty good at taking this unit out. I think I found the problem. It's not the charge pump at all. Looks like some different parts were used to rebuild this hydro in the past. The pins which compress the spring in the rotating group are too short. I think this makes the cylinder block seal poorly against the valve plate. So after I find some new pins I'll give it another shot. By the way the pins are NLA but should be 0.078" dia x 1.062" long.

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PhanDad
Not sure if this will be of any help, but in an earlier post, I think you stated there was an "extra" spherical washer in your Vickers unit. Maybe it (or a regular washer) was supposed to be there? On page 13-7 of the Large Frame Garden Tractor Service and Repair Manual, under step 17 there is the note: "On some units you will find a washer located between the spherical washer and the three support pins." Could this be the cause of the "short" pins and the difference in performance after initial repair?

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dave45056
PhanDad, According to Eaton, they never changed the pins. They have always been that length. I also noticed that statement about the extra washer. The motor on my unit has that extra washer, but the pump does not. The more I learn about this unit, the more I think the previous owner did a bad repair on it. The extra spherical washer was not supposed to be there. The short pins just happen to be the longest you can buy from McMaster Carr and Grainger. The spherical washer on the pump looks a little different than the one on the motor. The extra washer I found in the pump looks like a worn out version of the one in the motor. Soooooooo.... I think the pins need to be long enough to compress the spring in the rotating group. I think my unit does not compress that spring much, if at all. So my theory is that I am leaking by the valve plate and only sending a small volume of fluid to the motor at low pressure. I'll let you know if my theory holds water when I reassemble the unit again.

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dave45056
I ordered parts today. New pins, spherical washer, and shoe plate. I really hope my theory is correct. These parts aren't cheap.

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PhanDad
I too, hope the new parts fix your problem. Once the Vickers is running right, you'll love it. Looking forward to hearing how the repair turns out.

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dave45056
I'm clearly not qualified to write a how to on this yet. I am flying a bit blind and my latest attempt to fix it did not improve anything. Does anyone have any ideas?

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dave45056
I fixed it!!!! Works great now! I was looking into all the valves and I noticced a few differences between the Simplicity parts diagram and the Vickers version. The problem was in the spring arrangement in the soft start valve. Both springs can go in last as they work on different poppets. But on the Simplicity diagram it looks like 1 spring goes under the poppet and 1 over. The parts I bought before definitely needed to be replaced, so I don't think I bought parts for nothing. And there are no leaks! I can't tell you how happy I am right now... I even had my wife drive it around. I'll start doing some real work with it later on in the week.

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PhanDad
Glad to hear the good news. I'm sure you'll love a properly functioning Vickers hydro tractor. My Homelite T-12 with Vickers is my favorite. PS - I think you should put a note in your Vickers Tech Tip article about the difference in parts layout between the Simplicity and Vickers versions.

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TomSchmit
Hey Dave - No that you are so good at rebuilding the Vickers pumps, how about offering it as a service? I think I have one that could use this service! Tom

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dave45056
I'll update the Tech Tip artical. I also scpred another manual from Eaton for this unit. It's called M-2810-S T66 Overhaul Manual. I will add that to the article, too. One more thing... I have cross referenced the ball bearings and o-rings on this unit to standard numbers. I will add that info to the article, too I don't think I am good enough at this to charge people to do that rebuild as a service. But I sure have learned alot. So if anyone needs help or encouragement, feel free to look me up.

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