Now what do I do?

[HappyJack]

So I thought I’d do the responsible thing and check the differential fluid. I guess I didn’t have the drive all the way in the hole and the plug broke.
But I didn’t expect it to be so fragile. I thought it would be iron, not some sort of cast.
So now what? I could probably mangle it more and get it out, maybe. But where can a get a new plug?
Suggestions of removing and replacing is appreciated.
Until then I guess my diff is like Schrödinger’s Cat. It is both full and empty.

 

[The_Eagles’_Nest]

See if you can find and extractor to remove it, also heat is your friend. Use a torch to get it cherry and shoot it with penetrating oil until it cools, that helps to loosen up stuck threads.

 

[Jakter]

https://www.jalopyjournal.com/forum/threads/use-candle-wax-to-loosen-rusted-on-bolts.1035825/

Wire brush the area until clean, heat, apply candle wax.

After cleaning out the square hole, if there is not enough left to get a bite with the correct drive ratchet, carefully tap the plug in the direction of loose.

Take your time, it should come out.

 

[CBODY67]

First, might clean the area with some good penetrating oil. Then soak it well as the penetrating oil gets into the possibly porous "grunge" which is acting like a thread-locker. Might do this for a week or so, maybe? Might also use a smaller hammer to knock on the metal casting near the plug, which might also assist in getting the dry grunge loosened a bit?

During this process, might also fully clean the socket inset so the tool can get a full and solid engagement of the plug to get it out. After the first application of penetrating oil, might also wire brush the area around the plug and its threads.

Just some thoughts. Don't forget to hold your mouth "just right", too!
CBODY67

 

[Jakter]

CHLORINATED HYDROCARBON SOLVENTSVarious chlorinated hydrocarbons are used in degreasing or other cleaning operations. Thevapors of these solvents are a concern in welding and cutting because the heat and ultravioletradiation from the arc will decompose the vapors and form highly toxic and irritatingphosgene gas. (See Phosgene.)PHOSGENEPhosgene is formed by decomposition of chlorinated hydrocarbon solvents by ultravioletradiation. It reacts with moisture in the lungs to produce hydrogen chloride, which in turndestroys lung tissue. For this reason, any use of chlorinated solvents should be well awayfrom welding operations or any operation in which ultraviolet radiation or intense heat isgenerated




U.S. Department of LaborOSHA Office of Training and Education WELDING/weldhlth/1-95

 

[Just Carbs]

Drill and tap it for the next size down plug.
Use a vacuum for the cuttings as you drill.
Call it good for now and worry about it later.

 

[live4theking]

If you're going to heat it up and then apply penetrate I would be inclined to use this Freeze Off. The additional temperature difference will serve to help break the bond.

Salesforce B2B Commerce

www.fleetpride.com

I had to use it to get an axle nut off a car.

 

[Big_John]

So now what? I could probably mangle it more and get it out, maybe. But where can a get a new plug?

It's a pretty standard pipe plug that you can get at any well stocked hardware store. IIRC, 1/2-13 NPT which is .840" outside diameter. Look in the plumbing aisle. They won't have the 1/2" square hole drive. Instead it will be a male square. but that's what a lot of stock rears have.

Heat is your friend here, but think about pulling the center section out of the car as it may be easier.

If you want to, pull the left side axle (no adjuster on that side) and look down the axle tube with a flashlight. I think you should be able to see the oil level and it's easy to fill.

Until then I guess my diff is like Schrödinger’s Cat. It is both full and empty.

 

[MONC440]

Big John has it correct on this one for sure. Pull the left side shaft and add fluid if needed. It will be a bunch easier (and safer) than getting heat on that plug to get it out. Ever see what happens to oil caked parts when you put flame to them? Last thing you need is a fire a foot from your gas tank. Then this winter when the car is not being used drop the center section and do it on the bench.

 

[3C's & a D?]

Pointy, solid counter punch, tapping to turn loose. Move up to a small sharp chisel if no success. Both of these ideas have the potential to break away more of the plug.

You could also try epoxying a square drive in there, let it cure and cross your fingers.

 

[Jakter]

https://forum.millerwelds.com/forum/welding-discussions/18421-tips-welding-nut-to-broken-head-bolt

If you have a welder or know someone who does.

 

[Jakter]

While there is advice to pull the axles and remove the center section along with drive shaft and brake drums, you still have to remove the plug.

I would try removing it in situ before going through all that.

 

[WOT440]

Drill and tap w/left hand thread. Insert LH bolt and turn the plug out.

 

[fury fan]

I would clean all the crud off the plug, to prep for welding.

Get a short strap of steel, make sure it's short enough to rotate all the way around without hitting features on the diff casting.
Drill a hole with ID that fits over the plug, and weld it on.
Put visegrips on the strap and use it like a wrench.

Or make something else that would work better

A hex coupling nut might be a good choice, maybe get a larger size and grind the hex corners down so that it fits into the square.

But the benefit of using flat steel is that it gets the weld location right on the front, facing you, and easy to access.

Let it cool down before using, of course, because the welding will expand the plug and make it tighter in the threads.

 

[Rustyrodknocker]

Does the rear end leak? If so get the plug out while servicing the rear. If not, drive it.