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plastikosmd

that time of year and hydro issue

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plastikosmd
well i pulled the b12 out of the shed..on startup i noted the smell of urine..ugg..then the grass collecting on the rear of the grill..mutter...freakin mice. took off the top of the cowl and let her run..it spit out a ton of nest and 6 dead(ish) mice. Cleaned her up and blew her out..PITA. Now i gotta go check all the other machines. As I was bending down while running I nearly got hit with a stream of hydro fluid from my hydrolift in the eye. IF you didnt know, that top fill bolt has a hole for decompression. I tried to activate the hydro lever...it only bent the housing..no movement of the piston shaft. Shut her down, and noted the hydro tank was just under the temperature of the surface of the sun. Pump pulley/belt is free and spinning fine it seems. I removed the top fill bolt and fluid decompressed. Still no lever movement. Before I tear into her..any guesses as to the frozen piston/heat issue? The hoses are cold. I would assume the heat is due to the fluid running through a small opening in the valve body, Im not sure how the body decompresses once in up or down position..maybe it is always running, attempting to elevate or drop..dunno..open to guesses...guess i got another project.

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FastPaul
Not sure . I would take the hoses off an run it or turn it over and see if you got fluid coming out of both ports, I have five hydro's and some that have had some weird problems and it always has come down to sum type of o-ring failer in the lift cyl. Good luck

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plastikosmd
well not o-rings at this point. Tho after the teardown..we will see if we get a problem. The top of the piston/shaft was seized to the valve body housing along with the spring. That has been cleaned and fixed. I still dont know why the fluid heated up so much. I dont really want to tear into the pump, I dont have any gaskets that may be needed. What I need to know 1) Does the pump shaft run on a roller bearing or bushing setup? Would appreciate a diagram If a bushing, it feels fine..if a bearing...i will have to tear into it further thx

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GregB
Scott, Look at the picts at this link. Looks like bushings to me for the Gear shafts. [url]http://www.simpletractors.com/club2/topic.asp?TOPIC_ID=45048[/url] If the spool was stuck at the end of the stroke, maybe the pump was in bypass mode. Ie: the pressure relief spring and piston was putting all the pump output though the bypass channel. Pressure and narrow opening = increased friction and heat. As I recall there were attempts to develope heating systems around this concept. At work in injection molding with plastic, it is called the heat shear curve. The additional heat given to the plastic by pressure driven friction. Perhaps that is what is happening? Check out these links also: [url]http://www.simpletractors.com/club2/topic.asp?TOPIC_ID=40986[/url] Good info provided by other members.

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plastikosmd
that is what i figured...that it was 1/2 in and out..but by the way it is sitting now..at least with the way the valves are sitting...it would probably do the same thing..heat up..the plunger was seized right in the middle of it's action, i just hate to toss it back in and heat up..but it never had an issue..so this 'new seized' problem is probably the cause. will keep fingers crossed...the only other issue i could think of was a shaft issue..

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plastikosmd
well, all back together. looks like i didnt damage any of the o-rings..still holds after shutting it off..no leaks. Seems the problem was the piston in the valve body was stuck in such a way that the fluid must have been squeezing through, creating heat. Now the pump remains cool while running. Not too sure how it happened as the valve hasnt been moved in couple of months. Maybe after I started it i was just able to 'crack' it enough..for fluid to run by. well it was a 'simple' fix!

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D-17_Dave
Didn't see this thread until now. For every HP you put into the oil you must remove one HP. Since converting energy is never a 100 percent efficient thing, heat is created from the HP loss. In you case you most likely had the return to the tank blocked in a way that forced the oil flow over the tiny relief valve thus creating instant and tremendous heat in the oil. Glad you got it fixed as this could have destroyed the pump in short order.

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