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Discussion Starter #1
Hey,

Using the stock steel cover (1990 F350) and want to weld in a bung for a drain plug. Any of you guys do this? Got a pic of where you placed the bung?

Thanks,

Roy
 

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I have not done this,but I have been thinking about it and FWIW I would not go larger than 3/8" pipe plug, and I would weld the boss on the inside as low as I could get it with it offset to just clear the ring gear and use a socket head pipe plug. That way it's not easy to bugger up as it will be low and in front the front covers are plenty thick to make welding easy, and I bet with a little thought you could get it positioned to where it would still drain effectively and be as robust as the cover was without it....$.02
 

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Discussion Starter #3
Humm...thanks for the reply.

I can find NPT bungs for 1/4, 3/8, and 1/2 inch plugs.

I would not mind having a magnet built into the plug...but, a quick search didn't turn up NPT plugs with magnets. Only plugs using washers.

I would not mind leaving a cup, or so, of oil behind.

I am thinking of just to the left of the ring gear...when viewed from the front of the truck.

Roy
 

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Start with a black collar cut in half as a bung,and recess it into the cover that will weld nicely.
 

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if you want a steel one i have pipe taps up to 1/2" so i could make you one today if that will get you going ;)
 

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Look here as well
 

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I would do my best to get it as low as possible, the more you can drain the better seeing as the last will have the most crap in it.
 

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If you have a tap the size you want it would be just as simple to drill and tap the drain in the bottom of the housing
My $.02
If you want to go that route I have a tap you can use.
 

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Discussion Starter #13
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
 

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Discussion Starter #14
Anything more to the D&T job than this:


He, basically just says: slow drill speed, use cutting oil to drill, go slow; tap as normal.
 

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Go-Jo hand cleaner is the best tapping lube for cast iron.
 

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Discussion Starter #16
FWIW,

I have now read a bunch of posts saying drill and tap CI dry.

In any case, if I decide to add a plug, it will be in the cover...where any potential mistakes can be easily addressed by Guy-Of-Limited-Skill.
 

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I drill it dry but prefer water-less hand cleaner when tapping, but that is just my opinion after 40 years of machining.And machinists are an opinionated lot so you will get many answer to the same question where techniques are concerned.
 

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if you want a steel one i have pipe taps up to 1/2" so i could make you one today if that will get you going ;)
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 .
 

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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.
 
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