6 replies to this topic

[Bobbins]

This is the first gearbox I've rebuilt despite having done just about every other Mini based job available in the last 40+ years!  So I'd like suggestions regarding what parts and specialist tools I need?

 

The strip down is nearly complete, I'm just waiting on some more meaty circlip pliers that I've ordered following my last query, plus I also need one of the "3rd motion bearing removal" tools from Guessworks. John's website is currently showing them as pre-order so I might need to mock up something similar in the meantime.

 

I already have some parts such as a central oil pickup, but plan to renew the bearings (?), thrust washers, and clearly all the gaskets. At the same time I intend to fit a x-pin diff.

 

The gearbox had done around 55,000 miles and was suffering from the typical 2nd gear issue, difficulty selecting 2nd on the way up the box and would jump out of gear on the way down. Therefore which components do I need to correct this? Is it a "1st / 2nd gear synchro hub", or baulk rings, or both? I still find gearboxes a bit of black magic and need to get my head around what does what. Also selector forks? There was no sign of any debris in the oil.

 

Being aware there might be some expensive parts needed, rather than just buying a rebuild kit, if I can sensibly re-use any of the larger bearings it'll help to keep costs down a little. Everything will be going through an ultrasonic cleaner which will make it easier to check for any play when I reassemble the box.

 

The grubby bits ....

 

 

Gearbox nearly empty ...

 

 

And the first batch of cleaned bits, they look more worn photographed than they actually are and I'm very pleased with the result so far ...

 

 

 

Stu.

 

 

 

 

 

[Spider]

If you have an old Mainshaft Bearing, you can make your Mainshaft (Bearing) Removal Tool from that;-

 

 

Cut up the old bearing to look like this. I made that nearly 40 years ago, I've since made other tools for doing this job, tried them all, yet this is my 'go too' tool every time.

The other tool you may want is for re-assembling the Synchro Hubs. Again, I made this one (also nearly 40 years ago);-

 

 

You use it to compress the balls and springs thus;-

 

 

Then knock the inner hub with a soft mallet.

Parts.

As a minimum, you'd be looking at a Bearing Kit, Layshaft, Syncho Hub Springs, Baulk Rings, 1st / 2nd Selector Fork, usually diff parts, but you're fitting new I see, Gasket and Seal kit and a Speedo Drive Seal (these aren't usually included).

There may well be other parts, you'll need to inspect and check everything. You may also want to consider a Centre Oil Pick Up.

 

 

[KTS]

you'll be needing a sheet of some sort (a bin liner will do) to cover the mainshaft assembly as you extract it.

 

this will avoid hours spent trying to find the ballbearings that fly out of the synchro hubs if (when!) the collars over extend 

[Bobbins]

If you have an old Mainshaft Bearing, you can make your Mainshaft (Bearing) Removal Tool from that;-

 

 

Cut up the old bearing to look like this. I made that nearly 40 years ago, I've since made other tools for doing this job, tried them all, yet this is my 'go too' tool every time.

The other tool you may want is for re-assembling the Synchro Hubs. Again, I made this one (also nearly 40 years ago);-

 

 

You use it to compress the balls and springs thus;-

 

 

Then knock the inner hub with a soft mallet.

Parts.

As a minimum, you'd be looking at a Bearing Kit, Layshaft, Syncho Hub Springs, Baulk Rings, 1st / 2nd Selector Fork, usually diff parts, but you're fitting new I see, Gasket and Seal kit and a Speedo Drive Seal (these aren't usually included).

There may well be other parts, you'll need to inspect and check everything. You may also want to consider a Centre Oil Pick Up.

 

That's a fantastic help particularly regarding the make-shift tools! 

 

You mentioned the synchro hub springs but not the synchro hub itself, do new springs and baulk rings usually solve the 2nd gear issue?  I'm guessing renewing the layshaft is pretty standard.

[Bobbins]

you'll be needing a sheet of some sort (a bin liner will do) to cover the mainshaft assembly as you extract it.

 

this will avoid hours spent trying to find the ballbearings that fly out of the synchro hubs if (when!) the collars over extend 

 

You sound like you're speaking from experience ...!

[imack]

If it's jumping out of gear you need to check the condition of the dog teeth on 2nd gear and the dog teeth in the syncro hub sleeve.

[Spider]

I disassemble the hubs in a used Ice Cream container, covered over with a rag