13 replies to this topic

[minimissions]

Hi all me again sorry, i have taken my sump plug out of my car to do any oil change and as this happened, it brought the inner thread out of the inside of the gearbox casing.

Does anyone no the best way of getting round this? all its now does it leak, as it wont tighten up properly just spins?

Hope someone can help

Many thanks

[Globule]

You can helicoil the sump using a kit, but it risks swarf going into the gearbox when it is on the car (there are ways to minimise this)

Or I think Minispares sell a tapered plug for this purpose, but if there is no thread left, helicoil may be the only way

[ryan22_lgm]

my mate got a kit for this that re taps it and includes new plugs i will ask him

[mike.]

You can get cutting sump plugs which cut a new thread as they go in, but I don't think they're really designed as a permanent fix and i've heard they can crack the gearbox casing as they go in.

A heli coil is the only proper repair really, but would be very difficult to do with the gearbox in the car.

[ryan22_lgm]

i said it wrong lol he has a kit with a tap to tap out the hole and put a new plug in :)

[minimissions]

Ok thanks guys for your help, the gearbox is still on the car and yeah i am not sure on how to do this, my stepdad said he would be able to use and tap on it to get a thread back, but what plug would i put back in there afterwards as this would make the thread different (bigger). Does anyone have a link to any of these kits? or new plugs its a pain in the wotsit! lol! just drops all its oil!

Thanks for the comments :)

[dklawson]

If you are going to do this in the car, go ahead and buy the HeliCoil kit.

It is important that you keep swarf from getting inside the gearbox AND that the drill and tap are perpendicular to the face where the seal contacts. To do this, use a pillar drill to make a hole perpendicular to a block of some dense wood or scrap metal... something about 2" thick with a flat surface on one side. Then you can hold that against the sealing plug face on the gearbox and drill (more or less) perpendicular to the gearbox.

Pack the drill bit with heavy grease before starting. The grease will hold much of the swarf. Modify your guide block so its hole just clears the HeliCoil tap and use the block to guide the tap perpendicular into the casing. As with the drill bit, pack the tap with heavy grease to catch the swarf.

After you install the HeliCoil you will be able to use the "stock" Mini drain plug. However, I would look for nylon sealing washers to use instead of the copper washer. The nylon washers will crush more and easier than the copper and will compensate for any lack of perpendicularity introduced when drilling and tapping the HeliCoil hole.

[L400RAS]

I have seen this issue (and helicoil solution) posted many times, and always thought to myself, to help in removing any swarf that makes it into the gearbox, would it be best to refit the sump plug (once the work is complete), then refill the engine with *cheap* / the old strained oil, then remove the plug once more to hopefully "flush" any remaining swarf out? You could even do this "flush" multiple times using say 2 litres of oil at a time.

Then go ahead and refill with new oil.

This is only my idea - I have not experienced this - just works from the brain of Ryan...

Edited by L400RAS, 22 January 2012 - 04:23 PM.

[Guess-Works.com]

I avoid helicoiling in the car mainly because of the issues which DK has highlighted, getting the hole 'square' so to say is very difficult as you have very restricted access to the sump plug for a tap let alone a drill and bit.

But if I have to do one on a complete box, I run parts cleaning fluid through it afterwards... the same principle could be used by repeatedly flushing parts fluid down the dipstick hole and straight out into a bucket to remove the majority of the swarf...

[Tamworthbay]

I have seen this issue (and helicoil solution) posted many times, and always thought to myself, to help in removing any swarf that makes it into the gearbox, would it be best to refit the sump plug (once the work is complete), then refill the engine with *cheap* / the old strained oil, then remove the plug once more to hopefully "flush" any remaining swarf out? You could even do this "flush" multiple times using say 2 litres of oil at a time.

Then go ahead and refill with new oil.

This is only my idea - I have not experienced this - just works from the brain of Ryan...

Yes this is a good idea. It is also worth changing the oil and filter after a few miles (100-150) to be sure. A lot cheaper than the engine out and split option.

[tiger99]

I would only add that vacuuming out the residual swarf with a flexible tube through the hole afterwards may be another thing worth trying.

There is no other way to get access short of splitting the engine. You can actually get the left hand end casing and the diff off in the car, if you have the patience, but I don't think that either of those give viable access to the region of the drain plug.

This must have been a very common thing to happen when Minis were mainstream. What would a garage have done, left the swarf in, perhaps? There are not as many cowboys around nowadays, but 20 to 30 years ago, I do wonder....

By the way, the repair does not need to be a helicoil. Anyone with a lathe could turn up an insert, with a flat sealing face and the correct thread, which could be screwed (plus Loctite) or, if alloy, welded in place once the hole had been drilled out a bit larger. It eliminates the need for the hole to be exactly perpendicular to the face of the gearbox. Just depends on what facilities are available.

[minimissions]

Hi guys thanks for your comments and help it is good to no that this can be saved without taking the engine out :)
does anyone no where i can get this (helicoil solution), forgive me for being dumb, just never done this before. So does this add a new thead to enable me to reuse or buy a new standard sump plug?

i will use a mixture of your ideas to get rid of any excess metal as i no this wont do things any good, thanks for all the tips :)

i will need to get on with this so i can top up the oil and then run it for a bit, then move on to changeing the oil filter at a later date.

[dklawson]

Others will have to tell you where to buy the HeliCoil kit. There are other similar brands, one is "ReCoil". Basically, the kit consists of a drill bit, custom sized tap, inserts, and some form of installation tool. After you drill out the old threads you use the special tap to make new threads for the insert and then install the insert. Once the insert is in place you can use the regular Mini drain plug you removed.

[Guess-Works.com]

what you need is a kit for 5/8" UNC, it's unlikely to come with the drill bit because of the size required, I know the recoil kit does not