Saturday, March 7, 2015

Gearbox Rebuild - Part 1 - Selectors In

<This post is part of the 'Winter Project 2014/15 - (Gearbox Refurb)' project>

In the previous 'Gearbox Refurb' posts, I detailed how I stripped every single part ofthe  gearbox and assessed what I was going to reuse and what I was going to buy. Although I am waiting for the main centre bearing and some baulk rings to arrive, I am able to crack on and get the selector forks in the 'new' case. I say 'new' case, it's one that I stripped last year and spent quite a long time cleaning up, so it looks new.



I must admit the thought of rebuilding a gearbox seemed a bit overwhelming at first, but I've spent quite a long time studying this excellent video on youtube posted by Mini Mania. This post and the subsequent posts regarding the gearbox rebuild will document my experiences as I following Mini Mania's gearbox rebuild videos.


Selector Shaft 
The first job is to slide the inner part of the selector shaft into the Interlock spool sleeve and place it in the gearbox.

Interlock spool sleeve.
In this hole here...

... and into position.

Now to put the detent ball and spring in place to limit the selector shaft's movement. This makes it easier when putting the selector forks in place.

First the sleeve...

... then the ball...

...then the spring...

...followed by the O ring

I bolted the differential side cover temporarily in place to hold it all in place




Bell Crank Pivot Pin
Next job is to load up the bell crank pivot pin with all it's parts and the first one is the pivot bush, followed by the parts below.

Pivot Bush...
Reverse Release Lever...
Spacer...
3rd/4th Gear Release Lever, which is the pointy one...
Another Spacer....
1st/2nd Gear Release Lever, the NOT pointy one...
And Finally a Nyloc.



Selector Forks
With the bell crank pivot pin loaded up, it's now possible to install the selector forks. First the selector fork shaft is slid into its hole from the left, making sure that the hole in the shaft is towards the right hand side.

Selector Shaft.

The first selector fork to go on is the one for 1st/2nd gear. Here I had a choice of two different styles to choose from. One is stamped with the markings 'S-R19' whilst the other 'SR29', which I assume is a later type. The only difference I could see was that one of the forks was longer on the 'SR29' than the  'S-R19'.

'S-R19' 1st/2nd selector fork

'SR29' 1st/2nd selector fork



I'm not really sure if one type is better that the other, but the 'SR29' looked less worn than the 'S-R19' so that was the one I used. Regardless of which one I was though, they both are installed the same way, which was to align the notch in the fork with the upper bell crank release lever, then slide the shaft through.

1st/2nd selector fork in place.

Just like the 1st/2nd selector, the 3rd/4th selector fork came in two flavours also, being the 'SR18' and the 'SR28'. This one was really puzzling as I couldn't see any difference between the two. I chose the 'SR28', again on the basis that it was least worn of the two.

The notch on this selector sits under the 1st/2nd fork and locates on the lower (which is actually the middle, as the true lower is reverse) bell crank release lever, then the shaft is pushed through.

3rd/4th selector fork in place.

The final thing to do now is to tap the locking pin in place.



Reverse Gear
Next thing to install is the Reverse Gear. To do this, the reverse selector needs to be engaged by rotating (clockwise) the selector shaft down and in.

The reverse gear selector moves from here...


to here...


Now the reverse gear can be dropped in and it's shaft located through the middle.



The only thing to do is make sure the notch at the end of the reverse shaft is facing upwards.



Oil Strainer
The last thing I can do today is to install the oil strainer. I have one already cleaned up so I will be using that. It simply drops in place and is bolted up. This one had locking tabs, the other one I had didn't and would probably have needed some thread lock.




And that brings me to the end of what I can do today as I am now needing new baulk rings to build up the main shaft. So now I will just have to put the gearbox to one side and wait for their arrival. In the mean time, there is plenty of grot and grime to remove from the clutch housing.





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