Got ya.

Doug , I know of the two versions. I'm not trying to cut new threads. When I insert the compression threaded rod I want to clean the threads as I compress the cone. That is the reason why I suggested  putting in the additional slots in the threaded rod ( the slots act like a tap giving you space for the rust). You are doing two things at the same time.

Alex, if your comment about rubber mounted subframes is in response to my last post, I think you misunderstood.  I referenced the tap size in the "rubber cones".  The OP (Janedoe) and I both referenced rubber plugs regarding a method of sealing/plugging the tapped hole in the cones.  I don't remember anyone talking about the rubber mounted subframes.

6464, The OP said the tool they borrowed fits the cones removed but not the new cones.  New cones are tapped M14x2 while the early factory cones were tapped 1/2-20.  Since 1/2" is smaller than 14mm you cannot modify the threaded end of the old compressor rod to re-cut the threads, there isn't enough material in the new cones.  Regardless, the OP says they have already made their own puller rod for the new cones.

Janedoe, if you make those threaded plugs you were talking about keep a few things in mind.  The plugs need to be accessible so you can easily extract them.  The space above the cones in the tower is not easily accessed.  The plug threads need to be protected with grease or anti-seize to prevent them from getting rusted in place.  My preference would be to not fit any plugs.  If you need to clean the threads out later you can always weld an M14x2 tap to a piece of rod (as an extension) and chase the threads in the cone so the puller rod will engage.

Single bolt subframe = Mk4, there were no Mk3s with rubber mounted subframes...

 

No need for a separate tool. All you have to do is put a slot or two in the spring compressing threaded rod, there by making your own tap.

That makes sense.  The tool I borrowed fit the old cones but not the new ones so I made my own compressor tool to fit.  I have enough threaded rod to make my own capping bolts to keep the threads clean for next time and they too shall be massive.

Thank you.

Janedoe, The nuts of the cone are used for the specific purpose to compress or shorten the cone. The Two Massive bolts subframe to body bolts will "cap" your cone nuts. There are two different size nuts. NF 1/2 20 or Metric 14mm. Don't strip them. Spring compressor kits are available from our host or you can make your own.

Perfect.  Thanks to all.  This thread has been most helpful.   

I suspect Alex thought your car was not a MkIII based on your interest in the particular subframe bolt which is for a MkIV and later.  I don't decode VINs. Others here are very good at looking up the age of Minis.  However if you have already looked up your car's number and determined it is a MkIII I have no reason to doubt you.  

No... there is no plug for the rubber cone's tapped hole.  The rear cones can go in easily without an installation tool.  The front cones require a cone compressor to "shorten" them enough to fit the other parts.  The problem is that you cannot plug the threads of the cone prior to installation and once installed the threads are very hard to get to.  That being said, I am sure you could find a way to insert a rubber plug or similar if you wanted to.  Regardless, you might find applying a layer of heavy grease or anti-seize compound helpful as it will slow corrosion which might make future maintenance difficult.

The VIN plate, which appears to be original based on attachment and over all matching appearance with the rest of the car has it as a '74 XL2SIN.  I assumed that the cone was held up a bit.  

So just the compression of the cone by the weight of the front end keeps the cone/trumpet assembly in place?  Was there a plug that covered the hole where the compression tool was inserted?

It certainly is an interesting suspension.

Be aware that you don't have a '74 Mk3...

It is a post '76 vehicle as that was the changeover point for the big subframe tower bolts.

And thanks for all the replies.  Very helpful!!!

Massive bolt which I believe is called Subframe tower mounting bolt.  Part 21A2596.  Looked like it would have held the cone against the upper structure.  This is my first Mini, waited way to long to get one and went through too many Healys, TR- 3 and 4's.  The specimen I got has been missing quite a few parts but still a grear runner.

Looked like it went into the cone from the top to  stop chatter so to speak.

Two large bolts? 74 ?
Are you talking two long bolts each side or o e massive bolt each side.
They hold the sub frame.
Like they said...nothing is bolted to the spring

tight but not tight enough to crush it

If you are referring to the bolts that hold the subframe, I doubt there's a torque spec., just tight. 

+1 to 6464's comments.  No bolts secure the cones.

Can you direct us to a parts diagram or give us the part numbers for what you are talking about?

There are NO bolts holding the cones in place. The nuts welded to the inside of the rubber cones are used to compress the rubber donut in order to remove the trumpet. 

in the midst of replacing just about everything on a 1974 MK III.   Driver quality.  The two large bolts that hold the cones into place are backordered.  The Mini came to me missing quite a few bits including these.  How firm do they need to be installed?  I saw a torque setting somewhere but cant find it now.  Made my own bots until replacements arrive.

Thanks in advance.