Oil pressure sending unit

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PeteG41

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Location
Tempe, AZ
My Car
351c 2v, FMX Transmission. Ordered from Sanderson Ford in Phoenix, 99k original miles.
Alright I’m stumped. The sending unit on mine is definitely bad. No pressure on the gauge and a little oil puddle around it. Got the replacement, but for the life of me can’t get the old one off. 9/16 wrench didn’t give me the clearance, tried a crow foot extension and no dice. Not sure if the old one was Rounded off, I just picked this baby up. Any suggestions?
 

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I had to fight with one this weekend. A medium sized pair of channel locks was able to fit down to it and grip the body of the thing and break it loose.

Something else you can do, since its trash anyways, drill a couple screws straight into it and use a pry bar or bigass screw driver between the screws for leverage. My dad used to something like that when an old oil filter didn't want to come off. Hammer a screw driver through the side of it and you got yourself an instant handle.
 
I actually busted out some vice grips but don’t think the pair would have was large enough. I’ve definitely heard of that method for a stuck oil filter! I was nervous if I tried that the metal would be too flimsy and would just “rip” if that makes sense. Thought about getting a drill bit long enough to go straight through, sticking a screw driver through there and twisting it that way. With the channel locks, did you just grab it by the body of the unit?
 
A plumbers basin wrench might work if you have one. Somewhat similar to a crow's foot. The body might just twist around the shaft but might be worth the try. They come in handy and works great on various things.

View attachment 63795
Much appreciated! I tested the crows foot on the new one and it grabs, but with this being the original one its been on there quite a while and from what I can feel, might be a little rounded off. My fear of drilling through it and using a screw driver is that the metal is just to weak and will shear off.
 
When I was replacing the sending unit a few years ago, I had the same issue and I spent a looong time searching for something that would work. A 9/16" was needed but just needed to be a little longer than a normal socket. This appears to be a homemade socket that I found on ebay, most likely since nothing else was working for the person.

If you find something that works for you, thats good to hear.

If you want to modify a 9/16" the one needed looks like the following:
 

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When I was replacing the sending unit a few years ago, I had the same issue and I spent a looong time searching for something that would work. A 9/16" was needed but just needed to be a little longer than a normal socket. This appears to be a homemade socket that I found on ebay, most likely since nothing else was working for the person.

If you find something that works for you, thats good to hear.

If you want to modify a 9/16" the one needed looks like the following:
Yep thats exactly my problem, just can't get the normal 9/16 crow in there far enough. Thank you! I'll see if I can search around. Maybe even a stubby 9/16 but hate the idea of buying a whole other set just for that.
 
I have an old Snap-On Tools wrench made for the can-type oil pressure sender I use, but not worth the trouble of tracking down for the occasional use. I've owned several 351C and 429-powered vehicles, so it has come in handy. Before I acquired the Snap-On tool, I usually had good luck using a 9/16" crow's foot socket wrench or a short standard wrench, as others have posted. I've run into several of those where someone has already messed the 9/16" hex and left the mess for someone else. Some have tried to remove the switch by using the can. Occasionally it will come loose, and then as happens to most people, the can will break loose and spin on the base. Considering the location on a 351C or 429, the hex can be hard to get a standard wrench on. You may end up doing as I did once to help a friend who really messed his sender up. By the time he had decided he wanted to share this fun with someone else, the can was already sheared, and the hex was rounded out. There was nothing left to do then but to keep tearing it apart until nothing was left but the base. Just be careful to check for any metal debris before removing the threaded part of the sender from the block.

Even though I tend to plug Motorcraft products a lot, You don't necessarily have to use a Motorcraft sender. The Motorcraft gauge sender is Ford # E4ZZ-9278-A or Motorcraft SW-1547-B. If using a parts house such as Napa, Advance, etc., make sure you get something from their premium line.
 

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I have an old Snap-On Tools wrench made for the can-type oil pressure sender I use, but not worth the trouble of tracking down for the occasional use. I've owned several 351C and 429-powered vehicles, so it has come in handy. Before I acquired the Snap-On tool, I usually had good luck using a 9/16" crow's foot socket wrench or a short standard wrench, as others have posted. I've run into several of those where someone has already messed the 9/16" hex and left the mess for someone else. Some have tried to remove the switch by using the can. Occasionally it will come loose, and then as happens to most people, the can will break loose and spin on the base. Considering the location on a 351C or 429, the hex can be hard to get a standard wrench on. You may end up doing as I did once to help a friend who really messed his sender up. By the time he had decided he wanted to share this fun with someone else, the can was already sheared, and the hex was rounded out. There was nothing left to do then but to keep tearing it apart until nothing was left but the base. Just be careful to check for any metal debris before removing the threaded part of the sender from the block.

Even though I tend to plug Motorcraft products a lot, You don't necessarily have to use a Motorcraft sender. The Motorcraft gauge sender is Ford # E4ZZ-9278-A or Motorcraft SW-1547-B. If using a parts house such as Napa, Advance, etc., make sure you get something from their premium line.
Damn that looks like a pretty convenient tool! Yeah I am trying to make as little of a headache as possible, but that ship has sailed. My 9/16 is a little too long, so even if I get it to turn the tiniest bit, I run out of clearance. Couldn't get the crows foot to grab so SOL there too. Just like your friend, my fear is that if I go in there with vice grips or something the sender will just shear. I did however get the new one from napa so good to go there.
 
+1, use a combination end wrench, the closed end on the other end of the wrench is handy for using a screwdriver or prybar for leverage. I have several wrenches I have modified in one way or another, elbows, "S" curves, offsets, etc.

Edit: after heating it just let it cool in the open air. Quenching it may make it brittle.
 
+1, use a combination end wrench, the closed end on the other end of the wrench is handy for using a screwdriver or prybar for leverage. I have several wrenches I have modified in one way or another, elbows, "S" curves, offsets, etc.

Edit: after heating it just let it cool in the open air. Quenching it may make it brittle.
Looks like I gotta add a torch to the parts list at some point. Currently a townhouse carport mechanic
 
You might have luck with a 14mm wrench it is just a little bit smaller than 9/16 (.011" smaller). Being smaller it should get a better grip on the hex. I find 14mm and 9/16" wrenches and sockets to be interchangeable in most situations.
Going to try that as soon as I get home! If that doesn't work, looks like I am going with the vice grips.
 
I actually busted out some vice grips but don’t think the pair would have was large enough. I’ve definitely heard of that method for a stuck oil filter! I was nervous if I tried that the metal would be too flimsy and would just “rip” if that makes sense. Thought about getting a drill bit long enough to go straight through, sticking a screw driver through there and twisting it that way. With the channel locks, did you just grab it by the body of the unit?
Yep. I just grabbed it by the body and twisted. It. Don't worry about deforming the body of it, cause the more it deforms, the better your channel locks or vice grips fit.
 
Going to try that as soon as I get home! If that doesn't work, looks like I am going with the vice grips.
Once you figure out how to get a good bite on it, use a little heat from a mini handheld 🔥 thrower to “wake up” the threads. 👌🏻
 
Ooooo yep those look like winners! The one pair I have, I know...sad, don't have that curve so gripping it might be a little chore.
 

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