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MF50 Power steering, the Saga continues


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#1 coldone OFFLINE  

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Posted December 03, 2010 - 10:51 PM

Well this was supposed to be a thread on how great my power steering works now that I have fixed it, but that did not happen. We'll get to that in a moment.

First,
Relief valves, a story told under pressure

This is the lowly relief valve that protects my power steering system from being damaged by over pressure. There are many like but this one is mine.

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I must know it well, so lets take it apart.

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Oh look they come apart. Left to right, a "cap" a "valve" and a spring. Hey I new at least one correct term

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The "Cap", This is hollow in the middle and the part of the "valve" sets in the hollow section. The is where the output fluid of the pump passes over before leaving the pump. The hollow allows the "valve" to be exsposed to the full pressure of the system. This "cap" sets the tension on the spring when its assembled in the body of the valve. The further the cap is screwed in the more tension is placed on the spring.
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This is the "valve". The end with the hole is the end that goes up into the hollow portion of the "cap". The end withe the hole is also hollow which allows fluid to enter the upper end and then flow out the side holes. The spring keeps the valve seated firmly inside the cap until pump output pressure becomes higher than the spring pressure. When this happens the valve is pushed backwards against the spring and the two side opening allow fluid to pass back into the resivour through a series of passages within the pump.
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This is what it would look like if the system over pressurized and activated the relief.
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Here we see the "valve" unseated from the "cap" which would allow over pressurized fluid to flow through the cap, into the valve, and out the opening in the Assembly body where it would continue onto the resivour.
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This just shows how the cap is threaded into the body.
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Here is its happy home in the steering pump.

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This is the part of the story that is supposed to have a happy ending with me telling you that this relief valve was set to low and adjusting it fixed the problem with the power steering. Unfortunatly you will have to scroll down to the next entry.

Edited by coldone, December 03, 2010 - 10:58 PM.


#2 coldone OFFLINE  

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Posted December 03, 2010 - 11:19 PM

The relief valve was reassembled and reinstalled in the pump. I had bottomed out the "cap" and backed off two full turns. The tractor was cranked and and I tried turning the wheels. NO LUCK. I shut it down and pulled the relief valve and screwed the "cap" in another full turn. Reinstalled and tried again, still no luck. I then move my troubleshooting to the actuating cylinder and valve. (Diagram below)

I am able to disconnect the turnbuckle (b) from the pedestal and I operate the actuating valve by hand. The wheels turn easily, so it must be the linkages are out of adjustment. I consult the all knowing manual, I return and attempt to follow the directions. Some stuff is worn and its not possible to follow the direction to the letter. I end up tweeking the turn buckle a little ata time and testing the wheel. A little too much tweeking one way and I had steering only to the left, a little too much the other way only to the right. I finally get it dialed in (I tought) and I button up everything and attempt to go for a victory lap. I start backing up and I turn the wheels fully CCW to turn the tractor. When I turn the steering wheel back the other way only the front drivers side tire turns, the other one is pointing the wrong direction. :wtf:

It turns out the tie rod had come loose from the tire. When I got it back in my steering was back to not working and worse, I noticed that the engine was starting to bog down pretty severly when I was turning the steering wheel. I do not have a test gauge for this so I have to use some common sense and a little experience, both of them told me that the relief valve is set to high and something is causing the system to become overpressurized and that something is in a bad bind.

So the next step is to raise the front end and find out whats binding and possibly disassemble the pedistel. That going to have to wait until I have a few freedays. So stay tuned for the next exciting installment of "AS THE WHEEL TRIES TO TURN"

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  • cylinder copy.JPG

Edited by coldone, December 03, 2010 - 11:47 PM.


#3 caseguy OFFLINE  

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Posted December 03, 2010 - 11:34 PM

I like your style of posting very much! Keep plugging away and I'm sure you'll get it! And keep the pics coming.

#4 Bolens 1000 OFFLINE  

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Posted December 04, 2010 - 08:39 AM

I like your style of posting very much! Keep plugging away and I'm sure you'll get it! And keep the pics coming.


:ditto:

#5 olcowhand OFFLINE  

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Posted December 04, 2010 - 10:55 AM

I like your style of posting very much! Keep plugging away and I'm sure you'll get it! And keep the pics coming.


:ditto:


Same here, keep it up! :thumbs: Makes me thing of the soap opera..."As the World Turns", but in this case, "As the Wheel Doesn't Turn"! :D

#6 murphy OFFLINE  

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Posted December 24, 2010 - 03:45 PM

Are you sure lines hooked up correctly and are not opposing your turn each way?

#7 olcowhand OFFLINE  

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Posted December 24, 2010 - 03:59 PM

Are you sure lines hooked up correctly and are not opposing your turn each way?


Murphy, in his last post, he discovered a super tight spindle. I do wonder how that's coming along. How goes it coldone?

#8 coldone OFFLINE  

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Posted December 24, 2010 - 11:33 PM

Update soon, Christmas and work have kept me from typing. Its fixed though!




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