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Square head 1/4" NPT block water drains

rickseeman

rickseeman

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After 50 years, I can't take it anymore. I have to find the proper tool to remove these plugs. These plugs are square head .400" across. Yes, I can find square sockets. But not .400" across. Is there a Chrysler special tool for this? I can't fight this anymore. These blocks are over 50 years old and the plugs are stubborn. Yes, I can weld a nut on them and they've never failed to come out but I'd rather not have to do it that way. I have to find the proper tool to remove these plugs. Help me Obi-Wan Kenobe you're my only hope.
 
Are you referring to the female-recessed galley plugs in the back of the block? Since you can weld, maybe find an extra male square plug that fits into it and weld a bolt head onto it or machine/grind wrench pads into it. Or just find a piece of square stock to fit and turn it out with an adjustable wrench.

Use the Force Rick, use the Force.
 
rmchrgr said:
Are you referring to the female-recessed galley plugs in the back of the block? Since you can weld, maybe find an extra male square plug that fits into it and weld a bolt head onto it or machine/grind wrench pads into it. Or just find a piece of square stock to fit and turn it out with an adjustable wrench.

Use the Force Rick, use the Force.
Click to expand...
No these are male square. I need to learn about the Force.
 
4 point sockets

Screenshot 2025-07-01 204954.png
 
Last edited:
pnora: .400" is going to be tough to find. Chrysler has to have a special tool made by one of the usual sources for this. I have the FSM but I've never seen mention of a tool.
 
rickseeman said:
pnora: .400" is going to be tough to find. Chrysler has to have a special tool made by one of the usual sources for this. I have the FSM but I've never seen mention of a tool.
Click to expand...
I have never seen one. A well worn 3/8 drive sockets square drive end might fit the plug. Once you get one that could work you could weld a nut to it. . .400 is close to 13/32 and is a real odd ball. Majority of the ones I have seen were 6 point plugs. I have made male 4 point for female sockets out off old worn drive extensions.
 
For female I could grind down a 1/2" extension but this is tough to find. I've had to do that for a lathe chuck. I'm going to search the FSM a little. There has to be a Chrysler tool for Chrysler mechanics I would think.
 
I made the tool by grinding up a cap screw.
Never seen the tool you are after described in any manufacturers factory service manual.
 
I have used a 7/16" 8-Point socket for all my 40+ years of working on Mopars; no special Mopar socket needed.
 
I've never had any problem rounding them off with a 7/16" 12 pt. I figured an 8 pt wouldn't be much better, but I could try. I ordered an induction heater today. That will help.
 
This post got me thinking.
I remember when I was an apprentice we had a shop multi tool with various size square tips for plug removal.
I don't think this tool was a factory tool and I have not seen anything like it for many years.
 
The size mentioned above was an 8 point. This is a 4 point, much less chance of rounding off.
 
I ordered a 8 point 7/16" and an induction heater. If that fails I will buy a 4 point. But I think that will fail too. I will keep looking for a 13/32" 4 or 8 pt. I could make one from scratch but I'm so old and slow I hate even thinking about it.
 
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