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MG Midget and Sprite Technical - Differential Drain Plug Tool

I tried (and failed) to change the differential oil today. Couldn't get the filler plug out. I messed about for ages with a 1/2 in square drive socket which is what I read about in the archive, but it just kept spinning out.

Not wishing to cause any further damage is there a specific tool available for this job . . . I think I might be at the point where if I use the socket anymore I may cause terminal damage!
I Sterling

sounds like its a half inch square socket

you can get a a cast multi-fit drain tool but I've not them to be that good

or you could get a tool for a socket set

or you could get one that has it's own little bar or can be used with a (19mm?) spanner or socket over the tool to give more leverage (similar to photo)

for the work-
• clean around both plugs and spray with a penetrating/releasing fluid such as PlusGas (WD40 is not as good) and let it soak in as long as possible then try to slightly tighten, to break any muck/rust seal, before undoing

• have the axle oil as warm as possible before draining (protect yourself from hot oil)

• take filler plug out to help drain faster

• leave to drain as long as possible

• clean plugs and threads

• check axle breather is clean and clear

• refill with about ¾ of stated quantity of oil then top up very slowly until at bottom of threads leave excess to run out (can take ages if you overfill)

• plugs go back in 'dry' hand tool tight

for longer lasting oil with less cold weather drag you could use a modern alternative like Castrol Syntrax Longlife 75W-90 (GL-5 spec*) or Mobilube 1 SHC 75W-90 (GL-5 spec*)

(*GL-4 spec oil is recommend for the gearbox but the more modern GL-5 is considered fine for the diff)

Nigel Atkins

New plug and stilsons for the old one. Worked a treat on my sump plug and plug was OK to reuse after a little file dressing. I think Guy suggested it to me.
Dave Squire

Are you referring to the filler/drain plugs with the recessed square socket? If that is what you have then a 1/2" square drive almost fits but not quite.

I could not find a tool to fit the recessed plug. What I did was to get a 3/8" to 1/2" adapter and ground down the 1/2" male drive to match the recessed taper. See photo. I just snap it on to my 3/8-drive ratchet (or breaker bar if necessary) and out she comes.

If you have a plug with the external square drive, then a wrench, vice-grips, pipe wrench or whatever can be used. The thread on the plug is a standard pipe thread and the external drive plugs are readily available so just replace it if it is damaged. I don't believe the plugs with the recessed socket are still sold.

Paul



Paul Noeth

I have the same setup as Paul above. "Modified" 1/2" adapter.

Think mine was actually a 2" extension in a previous life
PeterJMoore

I've always found cleaning and penetrating fluid used as described earlier a longer handle tool for extra leverage have worked for me

if I was to use Stiltons I'd put a short 1/2" extension bar into the drain plug to reinforce the walls around the socket indentation

note - photo is of a 3/8" Hex socket drain plug
Nigel Atkins

When you finally get it out, go to somewhere like Plumbcentre and get a proper plug with the external head rather thanh the internals.

Removing mine last time was a real nightmare for all the reasons you mention. In the end the internals split and it was a real mess. Everytime I pulled on the spanner it worked it's way out of the drive. I even tried wedging a jack underneath to stop it working out. THey do have a certain notoriety!

I was changing the back axle anyway so it didn't matter too much.

G Williams (Graeme)

Paul,
the drain plugs I got are a 3/8" hex socket (well as I learnt here as I'm sure I was told they were 9/10mm when I bought them)

the problem with getting a drain plug with an external plug fitting on it is when fitted as a drain plug it sticks down a long way and you end up jacking the car up on the drain plug unless you use a thick bit of wood with a hole in the middle

there no problem with drain plugs with sockets if you use a new plug and the correct tool each time in future, the 3/8" hex socket is probably better than the 1/2" square socket though
Nigel Atkins

Thanks guys, but in the middle of all of your advice I happened to pop out to Halfords and found the perfect tool designed exactly for this task costing £5.99. Came home and tried it, fits almost perfectly apart from whenever I give the nut a tug the tool comes out. I did actually try it on the drain plug (it is the top up plug which is causing me the problems)and the drain plug does easily move.

I am just wondering if I can refill through the breather with a syringe! I understand from the books that the diff takes 1 litre of oil. Any thoughts?
I Sterling

The real thing:

Arie de Best

sounds like you might have bought the Draper 8 in one multitool I mentioned

try scraping the muck off around and on the drain plug and threads and clean as much as you can then spray a good penetrating/releasing fluid such as PlusGas (WD40 is not as good) and let it soak in as long as possible, overnight if possible

then as much later as possible then try to slightly tighten, to break any muck/rust seal, before undoing

if you have that multitool it's difficult to get anything on it to give it extra length for extra leverage and I found the same as you it slips

I cut and filed down the socket to get it a more snug fit

it's difficult to fill using the fill/level hole so I assume it would be more difficult through the vent

have a look in your Driver's Handbook for dry fill quantity as IIRC it's under one litre and bear in mind there's always some oil left in there from a drain so you're not doing a dry fill

also bear in mind if you don't remove the fill plug you can't check the level at services and see how much oil is in there to see what kind of loss there's been if any

try the spray and leave twice if really necessary before giving up on it - I thought I was going to pull my car off the axle stands and was about to give up when the drain plug on mine just started to move, a quick spray cup of tea and biccy to get my strength back and then it loosened and came out

Arie,
the Draper are very cheap and aren't cast as well as that one, the type I put a photo of earlier are much easier to use and you can use a spanner, large socket and extension on the handle
Nigel Atkins

Yes, this is my tool.

Am now drinking tea and spraying!

I Sterling

yes that's the tool I was putting that i found not much good whilst you were out buying it :)

see my first and other posts for more info on getting the plug out and drain and refill and oil types

you might want to cut and file the socket on that tool down a little too but its the awkward shape that mean you can't get a good hold on it to use much brute force and difficult to length it for more leverage

if it doesn't work tonight more clean and spray and leave until tomorrow

if you're using WD40 it might not work but you can get other tools that will fit better or look at some of the alternative methods in those other threads (there was a quite recent thread)


Nigel Atkins

Nigel, I did not know the drain plug came with a hex socket as well as a square hole, but I guess I should have realized that. I agree the external drive (fitting, head, or whatever it is called) is not the best because of the protrusion.

You say that the plugs go back in dry. Why is that? It is a pipe thread and I have always used pipe dope on plumbing connections. When I put the drain plug back into the differential I smear the plug threads with a little Hylomar and they have never leaked or dripped.

Paul
Paul Noeth

the hex seem to have replaced the square

I recently added 'dry' to make it easier to get the level plug out and I've put mine in 'dry' and not noticed a leak from them but I must admit if I was using them on water or gas it'd be pudding or PTFE tape used

if I'm wrong I'll change it, I'll perhaps put a thread up for consensus of opinion
Nigel Atkins

UPDATE : yes that tool is rubbish!
Tugged, pulled, jacked, braced it against the chassis with some 2x2 and the plug is still in. Looks like I will be grinding off a socket in work next week, failing that I suspect I will be running the car until the diff goes dry and have to replace it - having had the hassle of replacing bushes on the suspension a few weeks ago I really don't want to have to remove it just to change the oil.

Might list the tool on ebay . . . Only don't buy it! Doesn't work!
I Sterling

Remove hub and half-shaft and tilt car vertical on one side. The oil runs out one end of the axle casing.
Tip: remove brake shoes as the oil ruins them.
:-)

Or....

If the tool is working its way out of the socket, try gently pushing your hydraulic jack up undernesth so it can't back out.
:-))

One solution is more practicable than the other although both would work.
G Williams (Graeme)

did you try cutting and filing the (socket) I meant plug bit of the mulititool - it'll still be a useless tool but it might work, if not tonight then tomorrow

http://www.ebay.co.uk/itm/DOG-BONE-OIL-DRAIN-PLUG-SOCKET-WRENCH-8mm-17mm-AF-3-8-1-2-/180987701916?_trksid=p2045573.m2042&_trkparms=aid%3D111000%26algo%3DREC.CURRENT%26ao%3D1%26asc%3D27%26meid%3D5778635577653324288%26pid%3D100033%26prg%3D1011%26rk%3D1%26sd%3D180987701916%26

Graeme it's the fill plug that's stuck

sorry I've got to drive me wife to drink now she' home from work

drrrrrink

Nigel Atkins

I have used that tool and it does work, however it is difficult to get enough lereage on it and keep it in the hole.

I have also used a 3/8" ratchet with a degree of success.

I also bought some hex-socket plugs from Unipart/Rover about 20 years ago, so when I remove a square one, I replace it with a hex.
Dave O'Neill2

Lots of advice here, so here's my version:
I have tried those Draper style multifit spider things. I thought it was rubbish! The leverage provided is too short which means more effort is needed and it is difficult to simultaneously focus sufficient attention on keeping the thing engaged in the socket. And the design of the tool is such that it has a tendency to lever itself out of the plug.

I use a 1/2" square drive, ground down to a close fit, and with a decent sized torque wrench. It is just the square peg rather than a modified socket as this keeps the leverage closer to the plug and again reduces the tendency for it to lever itself out. The long lever means that relatively little effort is needed and you can concentrate on keeping the thing properly engaged in the plug. This seems to work best for me.

With a very tight one I have also used a little bit of heat from a propane torch which makes all the difference. It doesn't need much, and be careful not to set fire to it! Just remember the axle is filled with inflammable oil, and being in a confined space I expect it could result in an explosion. So extreme caution is essential.
Guy Weller

Like Dave, I have used a 3/8 square drive - usually with easy success. Being quite sloppy it turns and wedges in the larger square of the plug and this helps resist the plug's taper trying to push it out. On the odd occasion that this hasn't worked I also have a specially ground up tool.
Paul Walbran

I almost forgot... there is sometimes enough plug protruding to enable the use of mole-grips - AKA the Mexican socket set.
Dave O'Neill2

To add one more variation to this theme, here is the "tool" I use - it's a piece of square bar that fits snugly in both plugs with recessed heads. But, its 7/16" square, not 1/2". Then, just grab it with whatever works, usually a large adjustable end wrench.

Jack Orkin

I have a piece of square bar that is very similar to that, however, many years a local country garage welded a tommy bar to the end of it. This was when it belonged to my father, no longer with us, he found it a very effective tool.
Kingsley Dunn

I use a tommy bar with a sliding 1/2" drive on it. It came with a set of sockets years ago. I ground a slight taper to the drive to it fits snugly into the frain & filler plug sockets. As the torque is acting right up near the plugs rather than a few inches away - it just takes a few taps with a hammer to get things moving.
Dominic Excell

success!!!!!


Ground down an old 1/2 in extension bar at work and have just got the plug out!

Thanks for all of the advice. Now does anyone want to buy a Halfords drain plug . . . I wouldn't advise it!

I Sterling

I agree with Graeme when you get it out go to the plumbing supplies the thread is the same, image showes my brass hex head, use a little plumbers tape they don't stick out and i still use trolly jack to lift just place a soft pad on the jack head.

P Morrow

This thread was discussed between 22/02/2013 and 28/02/2013

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