32 replies to this topic

[BiMU]

For some reason the thread from within the sump hole has been striped.

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I was only supposed to change the oil and a few things today. Now this has really set me back and now really worried as I can't think of anything that I can do to fix it. I had a search and found something about helicoil kits... but I have no idea what that is.

Does anyone have any ideas?

[Dan]

Yes you need to get it Heli-coiled. Many local garages and engineers can do this for you and will often come to you if the car is immobilised. Buying your own Heli-coil set will cost nearly as much as paying someone to do it. It involves cutting a larger thread into the hole and using a special, very strong and hard steel insert into the new tapping. The insert is essentially a spring made of a diamond section wire so when one side of the diamond is engaged in the new thread, the inside of it forms a thread of its own and is the right size for the plug to screw into. Whoever does it you must make sure it's fitted properly, there is a tang on the inside end of it that must be carefully removed or it will be left in the gearbox. This is a permanant repair, unlike any of the temporary fixes available like tapered plugs.

How is the car Jason (it is Jason isn't it?)? Haven't heard anything from you for ages so I assume it's going well.

Edited by Dan, 09 September 2008 - 04:43 PM.

[BiMU]

Yes you need to get it Heli-coiled. Many local garages and engineers can do this for you and will often come to you if the car is immobilised. Buying your own Heli-coil set will cost nearly as much as paying someone to do it. It involves cutting a larger thread into the hole and using a special, very strong and hard steel insert into the new tapping. The insert is essentially a spring made of a diamond section wire so when one side of the diamond is engaged in the new thread, the inside of it forms a thread of its own and is the right size for the plug to screw into. Whoever does it you must make sure it's fitted properly, there is a tang on the inside end of it that must be carefully removed or it will be left in the gearbox. This is a permanant repair, unlike any of the temporary fixes available like tapered plugs.

How is the car Jason (it is Jason isn't it?)? Haven't heard anything from you for ages so I assume it's going well.

Hey Dan! Correct! It was doing well.. I joined my local mini club and so I learnt how to do a few things. But this has made me scratch my head a whole lot! I got the gearbox replaced a year ago or so and its been sweet as a nut, but obviously the little niggles like this I suppose still have me stumped! Hows your mini?

Just wondering how much I should be looking to pay for the Heli-coil and then how much for a tapered plug?

[Dan]

The Mini's fine, just been to Germany with everyone.

Tapered plugs are cheap but in the long run will wreck the gearcase. As for the cost of a Heli-coil, anywhere from £15.00 to £45.00 around here, if they have to come to you it might be more still.

[lotusk]

I had exactly the same thing happen to my mini at the weekend. I have ordered the tapered plug as a temporary fix but it hasn't arrived yet - for info I think it came to about £12 delivered. Link here: http://www.minispare....aspx?pid=32968

I'm a little wary of the tapered plug though as apparently they can crack the casing. I'll let you know how I get on with it but if you can afford it and have someone local, a Helicoil repair is the best option. I think people are paying in the region of £60-£80 but someone may be along with a more definitive price soon

Good luck with it and I'd be interested to hear which option you go for.

Kieran

[BiMU]

I had exactly the same thing happen to my mini at the weekend. I have ordered the tapered plug as a temporary fix but it hasn't arrived yet - for info I think it came to about £12 delivered. Link here: http://www.minispare....aspx?pid=32968

I'm a little wary of the tapered plug though as apparently they can crack the casing. I'll let you know how I get on with it but if you can afford it and have someone local, a Helicoil repair is the best option. I think people are paying in the region of £60-£80 but someone may be along with a more definitive price soon

Good luck with it and I'd be interested to hear which option you go for.

Kieran

Thanks, I think I'm tempted by the heli-coil option... But its too late in the day to ring around. I think I'd probably try and do it myself too... The tapered plug is also an option... But I think you'd need a lot of pressure to tighten up that bad boy! SO I think heli-coil. I'll let you know how it goes on!

Grrrrrrr... just when I thought the mini was fine!

[Guess-Works.com]

Give you a price indication..

To helicoil a gearbox I charge £25, but that's with the box stripped and on the bench where I have a jig in the pillar drill so the hole ( and thread ) are straight when done..

In the car it's a right pain as there's little/no room to get the tap in let alone a drill bit and drill.. look to pay £50 plus

Stripping the sump plug thread is ONLY caused by over tightening.... sump plug should be done to a max of 25lbft...

[BiMU]

Give you a price indication..

To helicoil a gearbox I charge £25, but that's with the box stripped and on the bench where I have a jig in the pillar drill so the hole ( and thread ) are straight when done..

In the car it's a right pain as there's little/no room to get the tap in let alone a drill bit and drill.. look to pay £50 plus

Stripping the sump plug thread is ONLY caused by over tightening.... sump plug should be done to a max of 25lbft...

Thanks for the quote... I guess I'm going to have to ring around tomorrow for someone to come out!

[BiMU]

Right! I've been looking around and found this:

How to use a helicoil.

If so... I remember doing this at college (some 10 years ago). I think I'm going to get a helicoil. I'm just wondering about the 'tang' I think its called... the thing that the guy just knocked out. If I do that... won't that piece be in the gearbox? Is there another way to do it?

[dklawson]

If you use a drift to tap the tang off the HeliCoil it will go in the gearbox. However, the 5/8" threads of the sump allow plenty of room to use needle-nose pliers instead. Grab the tang with the pliers, then push backwards and pull forwards back and forth until the tang snaps off and you pull it out with the pliers.

I have installed them with a gearbox in place but as John said, it's not an easy job. I had the advantage that I was able to rig up some angle-iron brackets that allowed me to align both the drill bit and tap so they were perpendicular to the sump.

Edited by dklawson, 09 September 2008 - 07:31 PM.

[BiMU]

If you use a drift to tap the tang off the HeliCoil it will go in the gearbox. However, the 5/8" threads of the sump allow plenty of room to use needle-nose pliers instead. Grab the tang with the pliers, then push backwards and pull forwards back and forth until the tang snaps off and you pull it out with the pliers.

I have installed them with a gearbox in place but as John said, it's not an easy job. I had the advantage that I was able to rig up some angle-iron brackets that allowed me to align both the drill bit and tap so they were perpendicular to the sump.

Ah schucks... So maybe rig up a 90degree bend on a piece of iron or equivalent piece of metal to guide in the drill bit? I don't suppose you have a picture of the brackets?

[Dan]

Buying a Helicoil kit to replace one thread is a bit extravagant. You can't just buy a coil, you need the right size drill and tap (both very precise) and an inserting tool. I can't remember the thread size specifically right now but it's somewhere around 5/8" UNC and a Heli-coil kit that size is going to cost you about £100.00.

The tang can be easily snapped off using long nose pliers on large threads like this but you have to make sure it doesn't disappear into the box. If you do decide to get a kit and go for it, remember to pack all the drill and tap threads with heavy grease first. This will trap a lot of the swarf produced in the cutting. Magnetised pliers would be good for breaking the tang, or a magnet tool or something like that (actually I don't know whether Heli-coils are magnetic or not). After finishing I'd be tempted to jack the near side of the car up some more so the sump drain is at the lowest point and then slowly inject some thin oil into the opening to wash it out as mush as possible. The magnetic nose of the plug obviously isn't going to help trap any swarf you leave because it's all aluminium.

<Doug beat me to it with most of that!>

Edited by Dan, 09 September 2008 - 07:40 PM.

[BiMU]

Buying a Helicoil kit to replace one thread is a bit extravagant. You can't just buy a coil, you need the right size drill and tap (both very precise) and an inserting tool. I can't remember the thread size specifically right now but it's somewhere around 5/8" UNC and a Heli-coil kit that size is going to cost you about £100.00.

Ouch... thats quite a lot of dough... I think a night to sleep on it then a ring around some garages maybe in order!

[raff8]

this happened me a few years ago and i got a taper plug, i race my mini and the oil is changed after every event so at a guess its been opened 40 or 50 times and it has never leaked a drop, and its easy to know how tight to go with them it just goes rock tight

[HARBER07]

I know im gonna get shot for this, but i tapped my sump plug out to something like 3/8" BSP or something like that. I then got an inline adaptor, wrapped it in thread tape and wound that in, and as its an inline adaptor it will never need to come out again, and stick a blanking plug in the end. Im probably explaining really badly but its late. Anyway the main thing is i done it with the engine in situ and was as cheap as chips to do. Never had a leak from the plug yet, just everywhere else!.