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Author Topic: Rebuilding A Hydraulic Shutoff Valve  (Read 4018 times)


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Rebuilding A Hydraulic Shutoff Valve
« on: August 30, 2016, 07:02:46 pm »
Well, I started out this morning with the task of replacing the o-ring that a friend at Delta found for me in the bottom of the shutoff valve.  After replacing it however I noticed that the top was pressing against the main fluid line coming from the resevoir.  I decided that while I was there I need to fix that so I got a wrench and turned it so that it was straight up and down.

Hmm, That feels a bit strange...  I get out and take a look at the extra valve that I removed from my spare commander and noticed that it was stiff with no play at all.  I got back into the back of the airplane and recorded this video:

Next I take it part a bit to see if I can figure out what is going on.  Hoping a screw is loose but knowing better.

After removing the top portion of the valve and placing it on the bench here is what I found:

It turns out that the bottom of the motor assembly was broken off on two sides and only 1 screw was holding it in place.  Definitely need to get this fixed.  Here are the steps and pictures along the way of removing all of the switches, wires, worm gear and pieces and replacing them with the ones from my plane.  I ended up with all my parts stuck to the bottom section of the old spare plane.

First how to get all of those wires disconnected and removed:

Here is a link to the gallery where I put the pictures of each step.  see pictures 25-56 for the related items.

The wires you see in the plastic tubes actually turned out to be plugs and were easily pulled apart and then later plugged back together.  The entire process ended up being pretty easy, just keeping up with all the parts and where they came from.  The hardest part of the job ended up getting that one
DAMN screw in on the opposite side of the motor assembly while in the airplane using a mirror and trying to put a flat head screwdriver on it.  Man is working in a mirror difficult! :-)

I also counted the worm gear as I removed it so that I could assembly it back at the same point.  The valve was shutoff obviously when the plane was shut down so had to make sure the switch was triggered at the same point.  I used my multimeter to trigger the switch in the off position and assembled everything else.

I also didn't get a picture of it but there is a spring and a ball bearing that fits into a hole in the plate that moves up and down.  I guess it is there to keep it from wiggling and binding up but you need to make sure you get it put back in there before putting it back on.  Other than that it was pretty straight forward.

By the way, I did search for a new valve and couldn't find even the part number online.  I was very lucky that I had a second valve to get the broken part off of so I could get it going again.

Entire process including the time it took to replace the o-ring and the typical on airport conversations of random people coming in was about 3 hours.

Hope you enjoy

« Last Edit: August 30, 2016, 07:04:22 pm by ghancock »
You can't win an argument with an ignorant person,  they'll just drag you down to their level and beat you with experience.


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Rebuilding A Hydraulic Shutoff Valve
« Reply #1 on: June 23, 2017, 11:26:07 am »
Anyone have a link to rebuilding a 140 Hydraulic pump that leaks into the engine?