12 replies to this topic

[eddyg]

Well basically just got my mini not to long ago it goes in for a service and in a previous one somone overtightened the sump plug.....i presume you know what happened next. Anyway they put in a helicoil but this came out the threads are not in good shape. What i am going to do it drill ou the hole retap it and put in a threaded insert made out of steel so the threads are stronger. I have almost got all the bits just waiting ofr the insert to arrive of the firm i got it from. Now has anybody had to do anything like this before?? I really don't want to bugger this up. Oh yea the sump was leaking hence the need to change it.
thanks

[Guess-Works.com]

If it's already been helicoiled and stripped again, you will either have to replace the sump plug with a larger one, and tap the whole to suite or replace the case...

If it looks like this then you're close to new case, this has not only lost the thread but the aluminum has started to corrode and break up, I'm going to try an experiment with this using a realy BIG sump plug but esentially Id be looking to scrap the case...

Is the engine in the car still, as with most things, if they have over tightened the sump, then if they have done any other mechanical work, then they are likely to be over tightened too... and it does not take much to strip the thread out of aluminum...

[eddyg]

NA it was only stripped hte once and not too badly. With the helicoil in it wasn't leaking but ehn when the guys did the oilchange the helicoil came out. I wanted a better solution. At the garage they manged to a fit a slightly larger bung used in plubing enough to get the car home but it was slowly leaking. hence i am doing this to try and ifx it. How hard it is to replace the case.. and what kind of cost are you looking at?!?

[miniboo]

click on guessworks link in his signature for prices on boxes.

[Guess-Works.com]

To refurb you box it'd cost 90, which would be 50 for the refurb, 20 for a replacement case and 20 for collection and delivery.

obviously you would have to remove and refit the box yourself.

[dklawson]

Have you already bought or made the steel insert you want to install? I tried a similar thing on a Honda years ago. The problem I had was the apes at the oil change places kept backing the steel insert out of the sump. I went so far as to degrease the threads and install it with structural Loctite. Still no joy. I ended up carefully drilling and tapping the Honda's sump for a 1/4" NPT pipe plug. Then I bought a BUNCH of nylon (not iron and not brass) pipe plugs that I carried in the glove box to use as drain plugs. EVERY time an oil change place saw it they said "We can fix that for you and install an oversized plug". And every time I'd tell them "you guys are the ones who stripped my drain plug out TWICE, just use my nylon plug and don't get ham handed on tightening it". I was in no mood to be nice.

You could do the same on a Mini sump, but you REALLY would need to modify the nylon plug to accept the drain magnet. What I would try instead is chasing the hole with the HeliCoil tap again and trying another HeliCoil. Make sure the ends of the wire insert are below the sealing face for the plug and seated properly in the threads and you should be OK. I've only seen HeliCoils back out under two circumstances 1) Thread sealant/locker (which shouldn't be used) was placed on the fastener (plug), or 2) the insert was installed in a way that the wire doesn't lay properly in the tapped hole causing it to bind on or bite into the fastener (plug).

If you, a mechanic, or a previous owner used a sealant or thread locker on your drain plug, that's likely why the HeliCoil backed out. You can switch to a nylon/plastic 14mm drain plug washer or a steel sealing washer with an o-ring bonded to its bore as a sealing washer instead of the stock Mini one. These require MUCH less torque to seat which will protect the sump thread.

[eddyg]

well i actually am being sent the insert for free of this company. Aparently it is too much hassle if i pay for it as i only want 1. It is a locking one as well. Once it is installed you hammer down these prongs and it locks in place. The guy told me the tap and drill bit i needed so i have already got them. I think from now on however i will do my own oil changes!! a least you know whats happened!!! The guy said that should get a tight fit. Somone at work sujjested puting ???PVTV??? tape or the plumbing tape just forgot it to help the seal between the insert and the sump.
It is one of the most annoying thing to happen tho!! and i only just got it!!

[Jammy]

PTFE tape, its plumbing tape. You can wrap it round joins to get a water tight join.

[eddyg]

thats the one! yea wrap that around to help the seal. Yes/No what do people think?

[Guess-Works.com]

Try it... anythings better than having to take the engine out !

[eddyg]

good good just checking that i wasn't being a total idiot. Will give an update of how it went!

[Dan]

Check with the company making the insert about the PTFE tape as it's teflon. It will greatly reduce the torque required to stretch the thread by the required amount to lock it up and could just end up with you stripping it all again as a result.

If a Helicoil is properly fitted then it shouldn't come out on it's own for a long long time (many duty cycles).

The traditional way to repair this thread after the helicoil has failed is to use a tapered sump plug (available from all Mini specialists). I have a problem with this however as the tapered thread is pretty much going to do more damage every time you fit or remove it and as such I don't see it as a solution. It only prolongs the life of the gearbox casing by an extra few oil changes rather than repairing the damage. I think this insert idea is a much better plan all round.

[eddyg]

yea i had looked into that with the tapered and there is also the worry that if you overtighten that then you can crack the case which would go from being a problem to a BIG problem