Stuck/seized diff drain plugs

Hi, basically checked the oil on my defender and the oil in the front axle really needs a change-it was black and grimey. I can get the fill plugs out of both diffs easily. Also want to change the rear oil as I have no idea when it was last changed.

I have removed all the accumulated grime around both plugs. Luckily the plugs are still completely square and not mushroomed. Sprayed both plugs every day for a week with lots of WD40 to try to get them to budge and no luck. Using an approximately 20/25cm extension for more leverage, tried moving the plugs clockwise and anticlockwise, I am putting enough effort into the bar to rock the car back and forth and even managed to strip a socket - neither budges at all and not sure what to do? Somebody suggested heating the plug but don`t think that`s particularly sensible due to the oil. Thanks for any advice

Only a 25cm extension? No wonder you're struggling. You need at least a metre long breaker bar. The first time I changed my oils I had to use a long breaker and brace my feet against the chassis, especially for the engine sump, but the axles were pretty stiff too.

Brilliant, that should make things so much easier! I am currently using something similar to this Laser Tools | 1578 | Drain Plug Key - 8/13mm Sq. so will buy a 8mm to 1/2 inch socket adapter to go with the breaker bar. Cheers!

sounds counter intuitive but try tightening it before loosening it.

On my axles the I/2" of the breaker bar goes directly in the plugs and I don't need a separate key. Try it on yours.

As Brown said, try a 1/2" breaker ( no socket attached! ). Good chance it'll fit. You can increase leverage by sliding any pipe over the bar ( as long as it's longer, of course ), no need for specific extended breaker bar.

I've had to use a jack to keep the breaker bar pushed fully home and stop it slipping out while heaving on it before

WD40 isn't the best choice for freeing stuck bits either. Try a 50:50 mix of EP90 and Acetone (nail varnish remover). 'Tis brilliant.

If you really, really can't get the damn things out I might suggest a vacuum pump (Mity-Vac or the like) and a tube - suck the oil out of the housing. it's definitely second best, but if it really doesn't want to budge it's a way around ttthe difficulty.

same as above, but also stick an extension in first and smack it once or twice with a hammer. helps to break anything sealing the thread.

if you fancy heating it but dont fancy using naked flame, try hot air gun, but sure the breaker bar will do it. make sure you dont rip the threads right out of it or you will be into a new diff cover.

Don't want to sound like a wet blanket but I had a similar situation with a brand new axle case some 6 years ago. I just couldn't undo any plug and had to resort filling the axle with oil down the side. When I tried EVERYTHING mentioned here, I went to a friend who's a mechanic who broke his 1/2" breaker bar on the drain plug! We had to resort to welding a bolt to the plug and undoing it using and impact wrench!

Thanks for all the suggestions! I am currently waiting on a 75cm breaker bar to be delivered from ebay, so will try that directly into drain plug. Will try using the jack trick, and if it still doesn`t work I will try the EP90/acetone mix . I will keep you updated

I second the jack trick.

Also, put your ratchet/breaker bar in and try and slightly tighten the plug - use the jack if need be to push the ratchet/bar up just enough to give it a decent little nudge. The slight tightening process can help to crack off rust on the bearing surfaces of the thread.

Then reverse the process and again using the jack if need be crack it off - I have done this many times successfully, use care and watch the boss on the pan carefully for distortion - if that happens give up or risk ripping the boss out. That ought to shift it for you.

Refit with some PTFE and cover the threads with a little anti-seize and you will never have that issue again.

I usually put as much tension on the breaker bar as I dare and then get an eager assistance to hit the business end with a hammer.

Thanks for all the suggestions, the breaker bar arrived which made it much easier to remover the drain plugs. Very glad I did the front diff as the oil that came out of it was black! I even took out both plugs and sprayed the inside with lots of WD40 to remove a bit more of the black oil. Are there any other similar jobs I can do on the defender, which will help teach me a bit about landy mechanics ? Also why does EP90 stink so much?!