Frozen Diff Drain Plugs, Solution, Kind of...

[Noflers]

The drain plugs on my rear differential have been stuck since I got the car. Every few days I go out and try/retry one of the various methods for getting bolts unstuck: heat, freeze, penetrating spray, etc. Basically everything short of using a bolt extractor, and I don't think that would even work.... The reason this is important is I have no idea how much fluid is in there, and how it looks. Also, the front shaft seal is leaking and needs to be replaced.

 

So I have a plan/idea (it's a plan unless someone here tells me I'm an idiot.)

 

1. park in my driveway with the front end pointing down (driveway has slight incline)

 

2. Pull drive shaft and seal.

 

3. Jack rear end up nice and high.

 

4. watch as the fluid drains out the front of the diff

 

5. (tricky part!) turn the car around so it's pointed up the incline.

 

6. Fill from the front of the diff.

 

7. Reinstall seal and shaft.

 

Will this work, am I an idiot, is there another/better way?

 

P.S. I might be able to skip step 5, I'd just need to make sure the diff is level before filling, meaning jacking the front of the car up a bit...

[datzenmike]

Complete filling your profile out so we know what vehicle you have and can comment on it.

 

 

I wouldn't. You won't get it all out and have no way to know when full. I don't even know if the oil will even go in there.

 

The pinion nut is torqued to provide a specific preload on the bearing. I wouldn't disturb it just for oil filling if indeed it will even work. If replacing the seal, you have little choice. I've done this before. I don't know what vehicle you are discussing but on an H-190 the pinion nut torque is 101-123 ft lbs. This is important so that the preload is returned to the same value.

 

The proper method for filling is the fill bung hole and it sets the level properly too. Penetrating oil doesn't work on a trans or diff bung because of the thread type. They are designed to seal oil in unlike a nut and bolt thread. Put a 2 foot length of pipe over your ratchet for leverage and raise the vehicle so you can pull downward with force.

 

The bottom drain plug has a magnet on it to collect ferrous metal particles. A black sludge is normal. Wipe it off before putting back so that you can see what's been collected the next oil change. Try an anti seize compound on the threads.

 

Replace with GL-5 80w90 or whatever is recommended by the manufacturer. LSD is different oil. The equivalent synthetic is also fine if using a new seal. If it leaks, synthetic oil sometimes can't be used because it is too slippery and leaks, replace it.

[Noflers]

Got it. It's a 510 with a Subaru 3.9 open diff.

Complete filling your profile out so we know what vehicle you have and can comment on it.

 

 

I wouldn't. You won't get it all out and have no way to know when full. I don't even know if the oil will even go in there.

 

The pinion nut is torqued to provide a specific preload on the bearing. I wouldn't disturb it just for oil filling if indeed it will even work. If replacing the seal, you have little choice. I've done this before. I don't know what vehicle you are discussing but on an H-190 the pinion nut torque is 101-123 ft lbs. This is important so that the preload is returned to the same value.

 

The proper method for filling is the fill bung hole and it sets the level properly too. Penetrating oil doesn't work on a trans or diff bung because of the thread type. They are designed to seal oil in unlike a nut and bolt thread. Put a 2 foot length of pipe over your ratchet for leverage and raise the vehicle so you can pull downward with force.

 

The bottom drain plug has a magnet on it to collect ferrous metal particles. A black sludge is normal. Wipe it off before putting back so that you can see what's been collected the next oil change. Try an anti seize compound on the threads.

 

Replace with GL-5 80w90 or whatever is recommended by the manufacturer. LSD is different oil. The equivalent synthetic is also fine if using a new seal. If it leaks, synthetic oil sometimes can't be used because it is too slippery and leaks, replace it.

[shacks510]

Could also try using the scissor jack to leverage the breaker bar while heating around the plug; around the plug, not the plug. Do the fill plug first. Don't drain it to find out the fill plug won't come out.

[datzenmike]

If the diff is full, the oil will draw the heat away faster than you can apply it. I've never had heat work so gave up on it. 1/2" ratchet end in the hole usually does the trick, with a piece of pipe over the handle to increase leverage.

[Stoffregen Motorsports]

It's not that hard to replace the diff cover. Buy one from a member here on Ratsun, lower the diff slightly, remove the mustache bar, remove the cover, install new and reassemble.

[datzenmike]

At the least it would be easier to get at.

[flatcat19]

Impact.

 

Use a 1/2" impact gun or hit ratchet/breaker bar with a hammer while turning plug...unless you've rounded out the plug.

 

I do this daily. Dumb people over torque fasteners.

 

Toyota uses plastic oil filter housings that constantly get over tightened.

1/2" impact breaks them free easily.

And this is plastic! You got this.

[Noflers]

Unfortunately I have tried everything mentioned here, lol. I'm gonna get it done this weekend no matter what!

 

I've never had such trouble with a diff before. I've replaced everything there is to replace on them, other than the gears themselves. 

[datzenmike]

Get a gym membership. It will come off as it went on. Just needs convincing. Be more convincing....

[flatcat19]

Air hammer and chisel?

[Draker]

If you've done everything here.. that thing must be on there good. A good impact with the appropriate amount of air should remove it no problem.

 

If it doesn't remove it... it should destroy it. One or the other.

[datzenmike]

Lefty... loosey.... rightey... tightie

[G-Duax]

Lefty... loosey.... rightey... tightie

 

Reading down through the thread, I was about to ask which way you were trying to turn it,

because more than a few times in life, I've seen people really tighten drain plugs when trying to remove them,

But Mike beat me to it..........

[Noflers]

Haha, I definitely have been turning it in the right direction. I have been known to turn a bolt in the wrong direction though.  :w00t:

[tr8er]

Turning it the wrong way with an impact can help break it. But less is more if doing that. Leverage is your friend, as is impact. Heat, while not expanding metal in the fashion you are used to due to oil, still softens everything making it easier. Termite is a bad idea though. Someone needs to invent nanobot thread looseners.

[G-Duax]

Leverage is your friend, as is impact. Heat,.

 

I have a very large 1/2" breaker bar, and at time add another 24" of pipe on the end of that.

Not all penetrating oils are the same.

I'm stuck on Liquid Wrench, but would never use WD-40.

Sometimes I use Liquid Lightning, due to it having such a high boiling point (500 degrees).

And I always use impact, but seldom an impact wrench.....

A diff plug, with a 1/2" square hole, I would use heat first, and as soon as everything is smoking, I douse with Liquid Wrench, and insert a 1/2" round bar into the hole, and give several good hits with a 3 pound hammer.

 

The shock helps the penetrant to penetrate.

This is usually all it takes to get one to come out.

[flatcat19]

Exactly. BFH fixes all. Or it breaks it. Either way is the correct path towards repair.

[Stoffregen Motorsports]

If the square shape gets a little rounded, you can bang it back into shape with a hammer.

 

Have you tried heating it yet?

[Stoffregen Motorsports]

I'm stuck on Liquid Wrench, but would never use WD-40.

 

I use WD40 exclusively and it never lets me down. I think it's more in the process than the product.

[scooter]

If the square is right fucked you could get a one inch nut and weld it on from the inside of the nut, and use a impact with balls or dont be a wimp with the breaker bar. It will come out

[Stoffregen Motorsports]

And the heat from the welding should be enough to break it free.

[Noflers]

Ended up breaking it loose today, with a 10lb sledge, 1/2" ratchet, and a modified dime for a shim.

[Draker]

Boom.. got it. nice.

[flatcat19]

Problem solved; post tits.