Hi guys

Mr dodgy from dodgy brothers mechanical repairs or the PO had stripped a thread on the drivers side diff case and neglected to

1) tell me

2) fix it

it felt strangely loose when I undid it to bolt my xtractors up. So then when I tightened it up I barely clamped the exhaust tab before it just span for a good length of time without moving in the inward direction.

I was visiting my local tool guru a while ago and he showed me these high tensile grub screw looking things with a thread on both the inside and the outside that you just screwed in and used a smaller bolt.

I think it cuts its own thread.

Anyone used em?

Failing that I will just tap it out with the next size metric bolt or something.

I could put a helicoil in but I would have to pull the cover off.

Has anyone else had the pleasure of doing this job?

thanks everyone

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Now it's stripped the hole is 5/16" diameter, perfect size to tap out to 3/8 UNC.
Tap it out, drill the hole in the cover to 3/8, and Bob's yer auntie's husband.
3/8 thread is harder to strip next time.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

could I do it with the cover on?

provided I drill the cover first?

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Those things the tool guy was talking about are probably called a keen sert
http://www.circletrack.com/techarticles ... to_05.html

I found one at work yesterday on the floor and had to spend about an hour trying to find out where it was from...... Still haven't worked it out.

Yes you can, just don't drill too deep.... you just want the cover to be 3/8...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Doc,

I am about to start my mini project and have been thinking about buying a tap and die set.

do i buy UNF or UNC or both?? :-S

Thanks

You will need both UNF and UNC for the car. Although you can get a few individual ones of each type and not be too concerned with the rest.

1/4, 5/16 and 3/8 in both UNC and UNF will get you through the car no problems on their own. About 80 percent of all the threads you will encounter will be 5/16 UNC or UNF.

BTW: If you have a stripped 5/16 UNF thread, you can purchase the helicoil to fix this (about a dollar each from repco or bursons etc) and use a 3/8 UNF tap to prepare the hole for the insert. I believe this is the only size and thread size on a mini you can do this without a specialist tap, but 5/16 is a useful size being the most common.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

All the gearbox threads are UNC. `Most' engine threads are UNF.
The thread you stripped is 5/16 UNC. Just go buy a decent 3/8 UNC 2nd (intermediate) tap, stay away from the crappy cheapo sets.
I only buy taps as I need em...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

The general "Rule of thumb" is to use the fine threads in steels ,,, & a slightly longer coarse thread type in alloys

Make sure it`s all nice & clean, spray both the new bolt & the tread in the case with lockquick primer & let sit for a while (as on the instructions written on the can of lockquick),,, then a dab of locktite "Nut lock",,, or "thread lock"

tighten it up & Bob`s your Aunty

Some guys even drill a small hole in the botl head & use tie wire to make sure that it doesn`t come out even if it loosens at a later date & on my race cars i weld 2x tabs on,,, one on the lower pipe & one onto the uper piece & then use a spring like on a go-kart pipe to make sure that even if the bot falls out then at least the pipe can`t fall off

insurance is such a good thing in the long run

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

I've got a doggy sump drain hole - original UNC thread has had a UNF thread forced into it and it's missing some bits on the edge. What should I do with it? Here is a picture of the hole and the two plugs I've got.

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David L


My greatest fear in life is that when I die my wife will sell my Mini and tools for the price I told her I paid for them!

I would get a 5/8-11 UNC tap and clean it back out.
If there are not enough threads left to hold the plug then, I would get it helicoiled.

<edit> that other plug looks like a 3/8 BSPT to me, they are about .010" smaller than 5/8.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I had one that was stripped, I went to an engineering place and they tapped it for the next size up. They had a rack of sump plugs for that exact job. Cheaper than a helicoil.

Tim

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1951 Morris Commercial J Type Van
1955 BSA C11G
1961 Morris Mini Traveller
1969 Triumph TR6R
1977 Leyland Moke Californian

We bought one once (in a $20 van) with the casing broken away that had a lump of hardwood bashed in there, it never leaked a drop.
It's an engine stand now....

Tapping it out to take a standard plug is good, but I'd drill a hole and press or araldite a magnet in there.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I think that is what someone has done with the plug on the left as the magnet can be pulled out of it.

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David L


My greatest fear in life is that when I die my wife will sell my Mini and tools for the price I told her I paid for them!

Gentle press fit better lasting than araldite, sitting in hot oilz....

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.