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Thanks guys.

I will keep the add-on magnet in mind.

Thanks eggman for the tap offer. I'll just buy one if I go that route. I have never drilled or tapped cast...

The D&T would certainly get it low. The drains on my Toyota diffs are all protected by a welded-on or cast-in ring around the drain. If I weld a bung on the cover, I might do something like that.

I am not much of a welder, and don't picture me welding a ring around a bottom plug.

Roy
I worked at Toyota for 20 yrs, the newer diffs are rolled steel , I would put a protective ring around drain plug. If you are not good at welding, how are you at brazing , it is kind of like soldering.
 

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I used to frequently add drain bungs to drag car housings and evolved a method that made them leak-free. I'd start with something like this: McMaster-Carr and cut it in half. Then I would turn a step on the end abutting the housing that was as wide as the housing metal was thick, and a common Unibit drill size roughly halfway between the ID and the OD of the coupler. The housing was then drilled to that size and deburred. Check fit and tune if necessary. On the inside seam I used silicon-bronze filler rod and ran a bead all of the way around. On the outside the bung got three healthy tack welds from a MIG. Then a piece of roll cage tube of a size that would fit down onto the housing outside of the tack welds was cut to be slightly longer than the bung with the plug in place. That got a full perimeter weld around it.
Q is that silicon-bronze for gas or is it a specialty ark rod
 

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Eggman. Have you tried to weld any of these cast iron fittings ? I tried such at NUMI & found them to be porous & terrible , maybe they were just cast & not cast-iron .
Also cast must be pre-heated to 600*F & useing machinable nickel, then cooled slow .
I would think it better to braze .
I have done a fair amount of cast iron welding at least for someone who is NOT a welder and I preheat the assy. to 350*F in an electric "broiler/oven" I picked up at a thrift store,I then weld and peen it then back in the oven draw it down and cool it over a couple of hours. The quality cast iron pipe fittings is kind of hit and miss but proper joint prep and heating/cooling will usually overcome that. The best cast iron tends to be that of vintage/antique items, don't know why but that is my observation.
 

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I worked at Toyota for 20 yrs, the newer diffs are rolled steel , I would put a protective ring around drain plug. If you are not good at welding, how are you at brazing , it is kind of like soldering.
I agree that if the iron is questionable that brazing is a good option..........
 

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I have done a fair amount of cast iron welding at least for someone who is NOT a welder and I preheat the assy. to 350*F in an electric "broiler/oven" I picked up at a thrift store,I then weld and peen it then back in the oven draw it down and cool it over a couple of hours. The quality cast iron pipe fittings is kind of hit and miss but proper joint prep and heating/cooling will usually overcome that. The best cast iron tends to be that of vintage/antique items, don't know why but that is my observation.
Steve I figured you probably know more about welding cast than I do ! My comments were more to others who might be reading this ! As for the plumbing fittings, l think the problem with them is - they are mostly from Korea
 

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Discussion Starter #26
I used to frequently add drain bungs to drag car housings and evolved a method that made them leak-free. I'd start with something like this: McMaster-Carr and cut it in half. Then I would turn a step on the end abutting the housing that was as wide as the housing metal was thick, and a common Unibit drill size roughly halfway between the ID and the OD of the coupler. The housing was then drilled to that size and deburred. Check fit and tune if necessary. On the inside seam I used silicon-bronze filler rod and ran a bead all of the way around. On the outside the bung got three healthy tack welds from a MIG. Then a piece of roll cage tube of a size that would fit down onto the housing outside of the tack welds was cut to be slightly longer than the bung with the plug in place. That got a full perimeter weld around it.
Right.

The HP fitting reduced iron welding issues, and the cage tube is to protect the bung. Right.

My welding is bad enough, I need something easy to weld.

I am now thinking of this:


Mild steel, with the machined step.

Roy
 

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Right.

The HP fitting reduced iron welding issues, and the cage tube is to protect the bung. Right.

My welding is bad enough, I need something easy to weld.

I am now thinking of this:


Mild steel, with the machined step.

Roy
Perfect, IF you can buy it locally, if not l am sure Steve would be more than happy to make one for you ! He could even make a protection ring ready to weld on .
You complain about your welding , are you useing - stick- if yes you probably are running cold & then long arking, this is the fault with most people , buy a mig unit & you can run innershild on it, if you like.that way you don’t need a gas bottle! If you buy from a welding store/ supply they will teach you how to run it
 

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Discussion Starter #28
I have a MIG with gas...but, don't want to get involed with welding cast iron, or such. I have two of those bungs in Post #5, I'll just have a go at welding one of them to some scrap.
 

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I have a MIG with gas...but, don't want to get involed with welding cast iron, or such. I have two of those bungs in Post #5, I'll just have a go at welding one of them to some scrap.
Irhunter is your name Roy ? Q#1 is the diff housing cast-iron ,or steel ?
#2 Is the diff out of the truck & stripped ? #3 As Steve Eggman posted (#20) it is important to remove ALL the oil ! _-“I agree !” #4 If you follow ntsqd post #20 AND that is brazing the bung into the housing ,from the inside, Looks like an excellent idea ! #5 IF the housing IS cast and you were to weld anything to it you would need to buy a small roll of machinable nickel wire & a temp heat pencil that melts at 600*f ! #6 if you put the bung in the cover plate you can weld both inside & outside / #7 when you practice. , no need the destroy 1 of your bungs , just set up similar
#7 When I worked for Toyota @ NUMMI , Fremont Ca / I found that most people tried to weld to cold & tended to long ark , even with mig ! If the material is not/ does not show blue & purple on the opposite side from the weld it is to COLD / there is not enough HEAT!
 

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Discussion Starter #31
Irhunter is your name Roy ? Q#1 is the diff housing cast-iron ,or steel ?
#2 Is the diff out of the truck & stripped ? #3 As Steve Eggman posted (#20) it is important to remove ALL the oil ! _-“I agree !” #4 If you follow ntsqd post #20 AND that is brazing the bung into the housing ,from the inside, Looks like an excellent idea ! #5 IF the housing IS cast and you were to weld anything to it you would need to buy a small roll of machinable nickel wire & a temp heat pencil that melts at 600*f ! #6 if you put the bung in the cover plate you can weld both inside & outside / #7 when you practice. , no need the destroy 1 of your bungs , just set up similar
#7 When I worked for Toyota @ NUMMI , Fremont Ca / I found that most people tried to weld to cold & tended to long ark , even with mig ! If the material is not/ does not show blue & purple on the opposite side from the weld it is to COLD / there is not enough HEAT!
1. Yes, Roy.
2. Yes...cover off truck.
3. Copy...no oil.
4. Yes, his plan sounds solid.
5. Not welding on the housing.
6. I will weld on both sides, for sure.
7. I have come to that conclusion, too. Just weld some similar scrap for settings, and go at the bung.
8. Copy...enough heat. Look at backside for signs of penetration.

Roy
 

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Q is that silicon-bronze for gas or is it a specialty ark rod
GTAW or TIG as most know it. "Heli-arc" if you're ancient. :)
Sil-Br goes down like brazing, only with a TIG torch instead of an oxy-fuel torch. I use it to seal and the healthy tack welds for strength.

I don't know why it persists, but Dana centers are not cast iron. They are cast steel. They weld like steel because they are steel. The issue with welding them is that there's a lot of metal there, pre-heat is a very good idea. So is post-heat. And if you want to be really anal about it, grab an HF needle scaler to peen the welds as they cool.
 
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