Suggestions please on tackling this rounded Transfer drain Allen Bolt, Pic Included

Attached pic Arghhhh!!!




I changed all the oils in my Cruiser a good while ago and ran into trouble with the Transfer box drain bolt, so I left it altogether. Decided to set about trying it again now whilst off on the Christmas break and its not going well at all.

Why they cant put a normal bolt on these things I don't know, but then again the stupid bolts they use when they do decide to use a normal bolt is'nt much better, they're a half skinny head on them and they rust and fall in on themselves and they're half rounded by rust and wear before you even go near them

Anyway, its a Hex 12 allen stud for this drain bolt, the inside edges were all rounded so I grinded down and hammered in a Hex 14 stud and tried the impact gun after I heated it a bit as well but that just rounded it out more to a complete circle.

I tried cutting a little slot into the edge of the bolt and hammering with a punch but this didnt work either and was afraid to keep going this method as it could end up damaging the bolt making it leak and still stuck.

Anyone got a suggestion as how best to proceed from here, the heat I used was a turbo propane gun, didnt get it orange like a oxy/acy torch would so maybe the oxy/acy heat and a punch is the next step??

Or maybe welding the allen stud into the bung would be a good idea, anyone know if the allen stud material will weld??
Feckin allen bolts

Weld a nut on it, also the heat from welding will help loosen it a bit

You can weld a nut to it? I would also try beating a torx bit into it they grip better then the next size hex bit.
Good luck really feel for you with that.
Stu

It really annoys me when people put knackard plugs back in when a new one is a few quid and can't be arsed to torque it up properly. The 80 I have just brought front diff filler is mashed to death it will need a nut welding on to to get it out

cwc said:

It really annoys me when people put knackard plugs back in when a new one is a few quid and can't be arsed to torque it up properly. The 80 I have just brought front diff filler is mashed to death it will need a nut welding on to to get it out

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Yeah, I hate people that put a knackered bolt back in as well, I assume garages do this when in a hurry and want to get the cars off the ramps quicker and just wont take the time to order a new bolt. I put all new filler and drain plugs into this as I went along but Toyota had to order them in so it was ok for me as its my own yoke and could wait but garages are always in a hurry.

stumog said:

You can weld a nut to it? I would also try beating a torx bit into it they grip better then the next size hex bit.
Good luck really feel for you with that.
Stu

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I was looking into that but didn't have a big enough Torx bit, my rails only go up to 10mm. I didnt have a Hex13mm either and from looking on the internet now these seem to be a rare enough size to find in a set in general, looks like I'll be ordering 1 of them from ebay to have in my toolbox if I should ever need it.

One reason why hammering at the edge doesn't work is because of the jam jar lid principle. When you try to get the lid off, you effectively distort the lid so it jams even harder. When you try to punch the plug round, you are squeezing and squashing the plug in the hole. Where things like impact guns score is because all of that 'twist' is in the centre. Even a large breaker bar applies a distortion load. Does that make sense?

So your best option is to try and apply an even, central twist. So, yes, welding on a nut is a possible solution. But you could set fire to the oil. Personally, I think at this point, I'd drill through the plug to let the oil out. You can go bigger and bigger with the drill after that until you can collapse the plug inwards or possibly knock it round with the punch. If you drill the middle out, you always have the option to buy something like a 14mm tap, thread the middle of the hole and put a new plug in.

Some ideas anyway. But you'll need a new plug for sure.

As said, welding on a nut is the way to go or maybe a short bolt with a thread size that fits snuggly in the hole. If you use a MIG welder I can't see a problem with the oil personally. The plug will be immersed in a few inches of oil so all you'll do is warm the oil up a bit. Draining the oil first means you more likely to set fire to the film of oil left on the plug and casing IMO. The heat from a MIG welder is also quite localised compared to welding/brazing with a gas torch.

Yes, but all of this presumes that MC can weld....

And that there actually is a few inches of oil in there

It also relies on very good prep. Welding to an oily old plug simply won't work. And, being vertical, it's not a particularly easy weld. And I can weld.

Cheers for the tips, I reckon the welding option is the way I'll go first before drilling it. Its a fairly big bung, there's a good bit of room to weld a nut on. I've a friend that can Mig weld it for me. I'm fairly good at drilling and tapping but I'd rather that as a last resort I think.

Is it the same size bung as the front diff? I have a couple of them lying around after I sold my 90 and took the scrapped diff to my local mechanic for disposal.
If you need one in a hurry I could bung it in the post?
One tool that works very well for these situations is a manual impact driver, I have a 1/2 one that takes sockets and it is quite easy to control for this kind of job.

Bounder said:

Is it the same size bung as the front diff? I have a couple of them lying around after I sold my 90 and took the scrapped diff to my local mechanic for disposal.
If you need one in a hurry I could bung it in the post?
One tool that works very well for these situations is a manual impact driver, I have a 1/2 one that takes sockets and it is quite easy to control for this kind of job.

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Cheers for the offer, I got all new bungs back in the Summer prior to starting changing all the oils. A couple of the new ones didnt match up but I think I have the new one for this. I have a manual impact driver but its past that stage now as the plug is rounded completely.

Do you havea 115mm angle grinder?

If so, look at the two-pin tool that you use to change the wheels - so you'd drill two evenly spaced holes opposite each other, insert the prongs and apply an even and steadily increasing force. Thing to be aware of is that the grinder tools are sometimes quite flimsy (not meant to need too much force), so maybe fab something up.

Before starting I would check the fill plug comes off first - be a bummer if you drain the oil out then cant refill it

Using old bungs can be a pain later, especially if threadlock has been used as well !

Pete

try heat and shock with a cold chisel , got mine this way

Try hacksawing a slot then impact driver. Have done this with success in past.


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I have the same problem with the 10mm fill plug on the front diff.!!!!! impossinle to drill, weld or grind in there because its up against suspension frame.!! can i top up my diff by filling it through the small breather pipe that comes up into engine bay.??? my 2 front inner seals are leaking very slightly. i will change them in a few months.

Watch the oil level closely, I ran mine low and ended up heating the front bearing up so it collapsed, allowed the pinion gear to move and it got jammed and bent in the crownwheel on a motorway.
Not great to have that happen to you.
You can drop the frames easily enough to get in to it.
Might be worth removing it completely to do the seals and the bung/s at the same time.

Thanks Bounder.! Does anyone know if it is a big job to drop front diff out to change inner seals or can it be done from each side.?

Its not a big job to drop the diff, immeasurably easier if you have a pit or a lift but I had neither and did it on my back on the driveway with a trolleyjack to hold the diff up so it could be bolted back in.
I think I undid the mounts and left them attached to the diff for ease of removal.
Mark the point where the driveshaft from the transfer case meets the pinion shaft so it goes back together the same way.
Seals pull out handily enough, I used a pair of fencing pliers to move the old ones out, the new ones were slightly different material from memory.
Need a long breaker bar to undo the front hub nuts, I had to buy a 3/4 slider bar and a socket to do the job, wife inside pushing on the brake pedal.

They do mostly go with a big enough chisel and hammer!



I did have one once that wouldn't budge though!!!

So I did this to it;















But it still wouldn't budge!

So I did this to it and out it came