Stuck differential fill plug

[Hirev]

Stuck differential fill plug... man just had to walk away and think about it till tomorrow very little room to hit 10mm hex socket with a hammer. The good thing is I have not drained it yet.

 

[BrianF]

Use some heat but an old trick taught to me by a mechanic was to tighten it first, if it breaks free, then you can loosen it.

 

[Gasbuggy]

Finally that trick pays off for someone. I had a brake line I couldn't crack loose once and I just hit it with a little pb blaster every other day for a couple weeks. Came out easy.

Put a pipe or half the jack handle on your breaker bar.

Otherwise, anyone make an aftermarket diff cover with drain/fill holes?

 

[oilboy123]

PB blaster and some heat. Breaker bar can't hurt

 

[Snagglefoot]

Does your square drive socket fit well into the recess? If not clean out the rust and dirt. Liquid Wrench is my choice as it does very well in the Project Farm head to head tests. Definitely apply it at least a few times a few days ahead. It’s well proven time helps.

If it still won’t come out. Apply heat with a propane torch. Oxy acetylene is better if you have a setup.
Liquid Wrench will smoke but not ignite.

I use a 12” 3/8 mini breaker bar to apply torque. Good luck. I’m assuming you can’t get an impact wrench into position.

 

[dnewton3]

What's the application? (year and model of vehicle?)
Got pix?

 

[RooflessVW]

Heat it up, smear some valve grinding compound on the tool you're using, and work it back and forth.

I have also had lock using and L+key and smacking it with a stout hammer.

 

[vwmaniaman]

On My GMC Yukon couldn't get fill plug out before I drained it so used my small size impact air driven impact from Harbor Freight that I bought just for low clearance areas. It hammered just a little and then came right out. Asked the guy at the lube place to check it and he used a breaker bar and could not get it out. So I am a believer in that small impact wrench.

 

[Snagglefoot]

Show us a pic on how much access you have at the plug. Can you get an extension to reach the plug and use an impact wrench?

 

[Snagglefoot]

Here is a pic of my 3/8” mini breaker bar.

 

[Hirev]

What's the application? (year and model of vehicle?)

2007 corvette so IRS differential is mostly buried got about 2 1/2" of working room front to back for 10mm hex.

 

[Hirev]

Can you get an extension to reach the plug and use an impact wrench?

Not room for impact wrench unfortunately.

 

[Hirev]

Use some heat but an old trick taught to me by a mechanic was to tighten it first, if it breaks free, then you can loosen it.

I'm going to try this