My rear diff fill plug is slightly deformed, please help!!

[93explorereb]

Greetings:


Does anyone have any syggestions on how one should go about removing a slightly rusty deformed fill plug for a rear diff (8.8)? My 3/8 drive would quite fit in the hole. Also the plug has become somewhat rusty and slightly corroded. I can't get a 3/8 snug enough into the plug to turn it! I desparately need to drain my rear diff as quickly as possible. I don't want to change my rear diff fluid via cover removal and be unable to fill. I was considering a decent cover with refill capabilities. However, many of these covers are quite expensive. Could I find something more reasonably priced. Also what could the shop do to nget this very stubborn plug to crack lose? What say you? Thanks in advance! 1997 explorer XLT 5.0 V8 AWD 124,000 PLUS original miles.


Best Regards

 

[marragtop]

First I would soak it down with PB Blaster. Are you saying you can't get the 3/8 drive to fit into the plug, or is it too tight to get the drive in? You can also try using a 3/8 breaker bar instead of a ratchet. You can beat on the breaker bar with a hammer.

 

[Carguy3J]

You could CAREFULLY weld a nut onto the fill plug. I'd weld through the middle/threaded part of the nut. This way, you can use a nut larger than the fill plug, and you minimize your chance of accidentally welding all this to the case. I would also do this with the cover still bolted down to the rear, as this should minimize the chance of the heat warping the relatively thin cover. At the same time, the heat may help to loosen the rust.
Once the welding is done, go ahead with the PB Blaster (yes, it matters. use this instead of wd-40) After soaking it down good, put a socket and big breaker bar on the nut and loosen your now less-than-stubborn fill plug.

 

[Elessar65]

You can always put fluid into a zip-lock bag and put the whole thing in the diff. I wouldn't do it permanently, but in an emergency where the cover is off and the fill plug is impossible to remove or something it should be fine for a while til you get a new diff cover. It will at least let you drive to get a new cover.

 

[IZwack]

If you know someone with a welder, install one of these on the differential cover:
http://www.summitracing.com/parts/MOR-85280/

Or if you dont know anyone and cant wait a few days, send the diff cover to me (I'm in the DC area) and I'll weld a large fine thread nut to the cover so you can use a large bolt as a fill plug.

 

[budwich]

I drilled a hole in the bolt using the "square" of the socket receiver as the "center punch guide".... as big a hole as I could 3/8->1/2 whatever.... then tapped the remainder with a thread for a normal bolt. You are taking off your cover and changing the oil anyways so no problem with the debris... which was basically nil. Others have drilled their covers and put a "rubberized" compression "nut" (ie. two rubber washers that are squeezed together by tightening the bolt)... if you search, you should find a few posts about that "method".

 

[93explorereb]

If you know someone with a welder, install one of these on the differential cover:
http://www.summitracing.com/parts/MOR-85280/

Or if you dont know anyone and cant wait a few days, send the diff cover to me (I'm in the DC area) and I'll weld a large fine thread nut to the cover so you can use a large bolt as a fill plug.

cool, Thanks!

 

[93explorereb]

Thanks guys you have been very helpful. I will try the PB Blaster approach again, and try to get this bolt off. Otherwise I may resort to the welding method. Thanks again guys!!

 

[gijoecam]

Apply some gentle heat to it with a propane torch. The threads are coated with thread locker that can be softened with heat. It doesn't have to get cherry red, just warm enough to melt the thread locker.

If that doesn't work, run a drill through it and use an easy-out.