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777funk

4130 skid steer Hydrostatic controls chatter (hard) while cranking. How to diagnose?

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I can shut off the engine making sure I'm in dead neutral and restart (still in neutral) and the T handle goes crazy when restarting. It also tries to move and stalls the engine before it can fully fire. Where do I start to look? 

I have replaced the filters and made sure there's plenty of fluid. 

Non stock items:

Diesel engine swapped in. 

Hydraulic reservoir moved above the door. 

25 micron lube filter in the tank (on the pickup). 

 

 

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It still does it even if I restart within a minute or two. 

Its worst if the engine doesn't start immediately (seems to intensify with more cranking). 

The linkage is a little sloppy for what it's worth. 

 

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16 minutes ago, 777funk said:

The linkage is a little sloppy fir what it's worth. 

Sloppy linkage will not hold the swash plate in nuetral.

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In your last thread, snoshoe said this:

"Chattering during cranking is caused by swash plates not being in true nuetral along with not enough charge pressure to hold pistons against plates."

Sloppy linkage seems like a logical cause for this.

It will get worse with cranking because you're not turning it over fast enough to create pressure, and the more the levers flop back and forth, the more the swashplate moves, and the more it chatters.

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ok so if i am understanding this correctly, mr funk would need to? 

1) get someone to stabilize the lever while cranking to keep the swash plate from being able to move which allows the opportunity for oil to eek thru a valve/plate which is allowing pressure to build against the turning engine

 2) unhook the linkage or lock the linkage with something to test the theory so there is no movement while cranking

3) scrap the whole thing and get a different skidsteer

 

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There is a spring loaded detent some where on the linkage to hold neutral. Any slop between that detent and the swash plate causes this. This includes the arm that attaches to swash plate. Any deviation from true neutral will cause this problem. Matt seems to understand and explain better than me.

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24 minutes ago, snoshoe said:

There is a spring loaded detent some where on the linkage to hold neutral. Any slop between that detent and the swash plate causes this. This includes the arm that attaches to swash plate. Any deviation from true neutral will cause this problem. Matt seems to understand and explain better than me.

There may be something wrong with my setup then because there is no neutral detent. I'll have to look carefully at the linkage and see if its there, but worn or if I can rig something in. 

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i would think you could FEEL some sort of detent - every hydraulic valve outside of a power steering type spool valve has a home position and i would think this type of a valve that regulates flow would have a home/stop position - kind of sounds like a loader type joystick valve with multiple holes in a center pivot position that allows for movement right/left - front/back - twist 

even our old old old valves you feel a home/sweet spot if you will where nothing is happening and everything is blocked off - I have levers/foot controls on my skid steer and am familiar with the GEHL units that have the T handle in them. 

I can feel the home position in the sticks and feet controls and just like a loader joystick, i would think that T handle would have spring tension to bring it back to home just like a loader joystick if you let go it should sit there. 

or maybe i am a baffoon and totally out of my head and how this thing works 

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1 hour ago, searcyfarms said:

i would think you could FEEL some sort of detent - every hydraulic valve outside of a power steering type spool valve has a home position and i would think this type of a valve that regulates flow would have a home/stop position - kind of sounds like a loader type joystick valve with multiple holes in a center pivot position that allows for movement right/left - front/back - twist 

even our old old old valves you feel a home/sweet spot if you will where nothing is happening and everything is blocked off - I have levers/foot controls on my skid steer and am familiar with the GEHL units that have the T handle in them. 

I can feel the home position in the sticks and feet controls and just like a loader joystick, i would think that T handle would have spring tension to bring it back to home just like a loader joystick if you let go it should sit there. 

or maybe i am a baffoon and totally out of my head and how this thing works 

Each (left and right) pump has a built in valve lever that connects to the linkage. I worked those valves by hand when I had it torn down. No detent or home in those. Maybe the linkage or control tower had one at one time. Not anymore if it did. Also a bit scary that it doesn't have springs to home the controls. 

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It took me a while but I remember now. Spring detent is a little misleading. Sorry about that. What there was is a lever under seat that when you got up locked both levers. There was another lever in front of seat that would lock seat in raised position. You would get in with seat locked up. Start engine then move lever to unlock seat. Seat would lower with you on it unlocking levers.

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Well it's been a while since I've been in one but I'm pretty sure it had some kind of electric clutch on a toggle switch up top somewhere maybe by the key. You could have it in the off position and you wouldn't have any hydraulic function like for starting or when you got out and let it run. Then flip the switch to on when you wanted to use it. 

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2 hours ago, jdetig1 said:

Well it's been a while since I've been in one but I'm pretty sure it had some kind of electric clutch on a toggle switch up top somewhere maybe by the key. You could have it in the off position and you wouldn't have any hydraulic function like for starting or when you got out and let it run. Then flip the switch to on when you wanted to use it. 

I also remember that. Am I mixing models or was there a change? Guess I better just sit this one out.

Doesn't change cause of chatter though. Those swash plates are not straight up and down. Those arms on the pumps that linkage hooks to are mounted directly to the swash plates. There are no valves as has been suggested.

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