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D200 Hydro Problems


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#1 coldone OFFLINE  

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Posted May 28, 2012 - 05:54 PM

I havent been posting much because I havent had much luck getting things going and finding the time to do it. This weekend I finally got the nerve to tackle the D200 and its problems. After the last vid of it I tried using it, it would go but had no real power in the hydro (sundstrand), it wouldnt even pull itself up the hill. I have been PMing Tudor (BIG THANKS TO HIM) and have been trying work through some of the troubleshooting. We went through all the little stuff, check valves, relief valves, accel valves, etc..I finally purchased a pressure gauge and fittings and the real troubleshooting started. My pressures are about where they are supposed to be at idle, underload the pressure drops to 0psi. There is obviously a leak somewhere in the system. I pulled the hydro motor and the "buffer assy" yesterday and started disassembling them today.

I started with the buffer, it is used when going from forward to reverse suddenly. It will bypass the sudden pressure spike to keep from braking things. It has two valves in it, one was stuck and had to be pulled. It also had some trash in it so i gave it a good cleaning and reassembled. I am not sure what the trash was but the PO had used gasket shelac everywhere, i think it was some of that but the stuff was too small to ID.

Next was the motor itself. I pulled the accel valves and disassemble them, cleaned and checked. Made sure the bleed holes were open, they are so small my smallest torch cleaned wouldnt fit I had to use a single strand of wire from a stranded 18AWG wire. I could pass air through the holes after that, didnt try before.

Next the cylinder housing so I could access the pistons and cylinders. No real problem there except for the shelac. The slippers on the pistons looked good and all the lube holes could pass air. I then pressed off the cylinder assy with the pistons still in. (This type has matched pistons to cylinders that are not interchangeable) After pulling the cylinder assy I could see the valve plate. It had very deep scoring in the mating surface and the mating surface of the cylinder did also. The manual says that if you can feel the scoring with your fingernail to replace the valve plate. The scoring could be felt with your finger tips, it was Deep and wide.

Being the type of person i am I figured nothing ventured, nothing gained. I broke out the flate plate and sandpaper. I started with 150grit and went through 2500 grit on the valve plate. (final thickness was 0.147inch) I did the same on the cylinders mating surface. Thouroughly cleaned both with carb cleaner and paper towels to remove all residue. Using lots of oil, i reassembled the pistons, cylinder,and valve plate.

Thats about as far as i have gotten. It will be a few more days before i have time to put it all back together and get new test results.

Here are some pics of the valve plate.

Edited by coldone, May 28, 2012 - 05:55 PM.


#2 coldone OFFLINE  

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Posted May 28, 2012 - 06:00 PM

As found
DSCF2846.JPG

Macro views
DSCF2847.JPG
DSCF2848.JPG

After 150grit
DSCF2849.JPG
DSCF2850.JPG

DSCF2854.JPG

After 600 grit
DSCF2855.JPG

#3 JDBrian OFFLINE  

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Posted May 28, 2012 - 06:51 PM

Nice work, and good info. Thanks for posting. The valve plate looks good. Chances are the shellac in the valves was your problem but it only makes sense to go through the entire unit while it's apart. The Sundstrand 15 in my 314 is really strong so I haven't touched it other than to repair the worn linkage to the swash plate. That should be a real strong tractor when it's back together.
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#4 olcowhand ONLINE  

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Posted May 28, 2012 - 07:11 PM

What did you use for backing under the sandpaper? The plate looks great! My Massey 1655 (now 1855) had a bad hydro. Was the same thing wrong with it. I was lucky & had spare parts, but I have turned these plates & cylinders on a lathe & worked great. If you had a good perfectly flat backer, this should give you great results.
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#5 coldone OFFLINE  

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Posted May 28, 2012 - 08:49 PM

I have a 12 inch aluminum sanding disc for my Shopsmith that i use as a flat backer plate. I used one of the 3M rubber sanding blocks on top of the valve plate to help minimize the uneven pressure of my hand plus I rotated the valve plate every few strokes. My biggest fear is to get the plate out of paralelle. For the cylinder assy I just rotated the assy every so often.

Its encouraging to hear that you have sucessfully turned these plates on a lathe and have good results. I cant wait to get the motor back together and on the tractor so i can see the results. I am guessing that i will have to do the pump also but I hope not yet.

#6 caseguy OFFLINE  

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Posted May 28, 2012 - 09:14 PM

It's hard to believe that those are the same part in all the pics! That's some great work! I'll be watching to see your progress!
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#7 bgkid2966 ONLINE  

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Posted May 29, 2012 - 11:36 AM

This makes me worry about the condition of my hydro. It works great now. When I got the Cub it had just resurfaced from a garage that was under 12' of water. :confuse: :confuse:

Geno

#8 coldone OFFLINE  

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Posted June 02, 2012 - 12:07 PM

SUCSESS!!!!!!!!!!!!! :dancingbanana: :dancingbanana: :dancingbanana: :dancingbanana: :dancingbanana: :dancingbanana:

I now have 100PSI at full throttle neutral and above 50psi in full forward and reverse! Implement full stroke gives me above 750 psi and It can pull the front tires off the ground!

Video later this evening.

Edited by coldone, June 02, 2012 - 12:09 PM.


#9 Texas Deere and Horse OFFLINE  

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Posted June 02, 2012 - 12:39 PM

Glad you got it fixed, you are now a Hydrostat expert, We will have to make this a pinned thread. Any other photos or info you can add will help other out. Thanks again for sharing... :thumbs:
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#10 chris m ONLINE  

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Posted June 02, 2012 - 12:42 PM

Thats great!!!!!!!!!!!! Congrats on getting it fixed!!!! I bet you are out playing on it right now. :bounce: :thumbs:
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#11 olcowhand ONLINE  

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Posted June 02, 2012 - 12:53 PM

Glad you got it fixed, you are now a Hydrostat expert, We will have to make this a pinned thread. Any other photos or info you can add will help other out. Thanks again for sharing... :thumbs:


Yes Britt...you are now on the "Hydro Payroll". Your checks for your services will come in the mail......just keep watching for it to arrive! LOL Glad you got it working & even more glad you posted your work!
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#12 bowtiebutler956 OFFLINE  

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Posted June 02, 2012 - 03:31 PM

Great job on your hydro, the D-200 is heavy duty Horse, and a great machine. Congrats! :thumbs:

Matt :orangecool:
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#13 coldone OFFLINE  

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Posted June 02, 2012 - 03:47 PM

Vids postponed until tomorrow. Everything is ok. wifey says I have to take her out tonight. But i did get to mow wirh it.

#14 coldone OFFLINE  

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Posted June 03, 2012 - 11:03 AM

Got a little time for some write up.

I left off at just having reassembled the cylinder assy and installing it on the shaft. I started the day off by cleaning all the old shelac off of the housing. It was everywhere. I found that the carb cleaner I had would disolve the shelac. I put the housing back on and performed a final check of the accel valves before I installed them. A final cleaning and off to the shed to put it all back togetner again. The motor to tranny gasket was glued on with the same shelac so i had to get it off being very carefull not to get any pieces into the trany. I had pulled the entire rearend to get the motor off so most of the day was spent putting it back in. Once everything was back together I fired it up and let it idle with the wheels off the ground so it could prime itself with no load. the pressures during this were pretty much the same as before until I checked the implement stroke. The gauge jumped up to 750-800psi! (remember that I left the homemade third shim in). I turned it off and dropped it back to the ground for the test run.

The test run was great. The preesure stayed above 50 psi all the time and the tractor felt like it had power. The test run was short about 5 minutes. I was satisfied with the operations so I pulled the deck out from under the d160 and put it on the 200. I left the pressure gauge in place and started mowing. I did not have any problems at all while mowing. The needle was jumping around due to vibration but would dampen down whe i held the gauge. It was still holding above 50 psi after 30 minutes of hard mowing. Since the pressure gauge i am using is 1/4 MPT it has to go where the temp sending unit goes so I was unable to see the temp. When I got through (about 45 minutes total) I felt the hard lines they wernt bad at all. Hot but water didnot boil off when applied so they were less that 212F (100C).

A few things i noticed:
1: When applying the brake with coldish oil. It will throw you out of the seat Posted Image
2: When going slow and you are making sharp turns the tractor has a tendency to slow down also noticed when this when going up small hills in the yard. The pressuer never dropped below 50psi and a small bump to the Motion control lever corrected for speed. So I think this is normal for a hydro system.
3: The D200 Is very much a beast!

I am not sure if the accel valves had a clogg or not or if resurfacing the valve plate and cylinder block fixed the problem. Personally I am going with the resurfaceing. There were a lot of deep scores in both pieces. Seeing that these two pieces seal together with nothing more than close tolerances I belive the scoring allowed too much oil to bypass going into the cylinders. No oil presssure in the pistons and there is no movement.

I am not going to fool myself in thinking this tractor is totally fixed. I believe the pump is going to have some scoring in it also. I just want this for mowing duty now. So I plan on pulling the pump this winter and checking it out.

ETA: The implement pressure with hot oil dropped to btween 600-650PSI. I made a lead washer for the sealing washer on the manifold bolt. I will be checking this for leaks.

#15 olcowhand ONLINE  

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Posted June 03, 2012 - 11:16 AM

Having never been around a D series, I have to ask....isn't the motor a gear motor & not a piston unit? I know the C series were gear motor, and the GT14 as well.




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