Rear differential fill plug.

Reply Subscribe

Thread Tools

Search this Thread

Feb 10, 2006 | 11:10 PM

1978Supercab

Thread Starter

New User

Joined: Apr 2003

Posts: 10

Likes: 0

Rear differential fill plug.

I have a 1984 Ford F-150 4x4 and I am having trouble removing the rear differential fill plug. The fill plug is really rusty and there is almost nothing left of the square hole in the center I tried turning it out and the 3/8 drive extention wants to slip in the hole. What would be the best way to try to remove the plug?

Feb 11, 2006 | 01:24 AM

Larry_the_handyman

Senior User

Joined: Aug 2004

Posts: 327

Likes: 0

From: Los Angeles

Start by soaking the plug with WD-40 two or three times a day. If that doesn't work after like two days, you may have to weld a bar onto it so you can grip it. Hopefully somebody will have a less drastic approach, but it's late and that's all I can think of.

Feb 11, 2006 | 01:42 AM

ford390gashog

Fleet Owner

Joined: Jan 2004

Posts: 26,007

Likes: 575

From: Brentwood,CA

well you may have to weld a piece of rebar in the hole and take it out that way.

Feb 11, 2006 | 04:01 AM

1978Supercab

Thread Starter

New User

Joined: Apr 2003

Posts: 10

Likes: 0

I'm thinking about putting a bolt in the hole of the plug and welding it to the plug. Then trying to turn the plug out with the bolt. The heat from welding it should also help break the plug loose. I know I have to watch how hot I get the differential housing because of the seals and the fluid in it, but I think this will work. What do you think?

Feb 11, 2006 | 05:35 PM

Larry_the_handyman

Senior User

Joined: Aug 2004

Posts: 327

Likes: 0

From: Los Angeles

The heat from welding it will cause the plug to enlarge, so try to keep it to a minimum. If you just tack a bar across the plug you won't have to worry about grabbing the bolt and twisting the welds off the shaft of the bolt. You want your tacks to be close to the edge to give your more torque on the plug and less force on the welds.

Feb 13, 2006 | 07:36 AM

Pkupman82

Postmaster

Joined: Feb 2003

Posts: 3,441

Likes: 5

From: Muskegon, MI (home)

I have been able to get those plugs out if there is a little bit of the plug sticking out of the case. I just use a cold chisel and a hammer and whack it a couple times along the top edge of the plug, usually this is enough to break the rust free. Next time I have to take my plug out I'm going to replace it with a pipe plug with the square on the outside.