Wednesday, March 4, 2015

Gearbox Stripdown - Part 2 - Gears Out

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

In the previous post, I got to the point where I needed to get the nut off the first motion shaft, but didn't have the necessary 1 1/18" deep socket to do the job. Rather than just buy a single socket, I decided to buy a bargain basement set of sockets from ebay that included the one I wanted.

Arriving 1 day earlier than expected, I was very pleased with my £29.50 investment as these sockets will come in handy for a number of things I'm sure. But now they're here, it's time to crack on with the gearbox.

Yeah!!- New tools!!

As there's quite a lot to explain in this post, it ended up being quite long, so to keep it interesting I tried to make it more picture based and less wordy. Hopefully this will make it more understandable also.

1st Motion Bearing
So opening my new socket set and using the 1 1/8" socket and my breaker bar, I turned the gearbox upside down to stand on it with one foot. Having already 'locked' the gearbox in Part 1, I attached the socket to the nut and pressed down on the end of the breaker bar with my other foot. Without too much effort, the nut came loose.

Whipping the box back over, the rest of the first motion shaft stuff could be taken off and stored away safely.
1st motion shaft.

Now the tricky circlip needs to be removed. I had a problem with this in the past when I stripped a previous gearbox as I didn't have (and still don't have) the correct tool, but searching through my random tool collection, I found a pair of long nose pliers that worked perfectly.

The tricky crclip

Now back round to the other side of the gearbox to get the 1 1/2" nut undone.

This nut in fact!

Having already removed the speedo housing cover in Part 1, access to the nut is through that gaping hole it leaves. Here I will need my Really Big Socket (1 1/2"). It's the same one I bought from Mini Spares last July to work on the wheel hub balljoints. Handy!!

Same as before, gearbox upside down, socket on the nut and stand on both to undo the nut.

Thankfully the socket clears the housing!

Once the nut is off, there are 3 other bolts to undo that hold the 3rd motion bearing retainer in place. If you are wondering how I know what all these widgets are called, I nicked the knowledge from Mini Spares website here

With the retainer removed, the pinion gear, locking plate and shim can all be taken out now.

Now we are getting somewhere! It's amazing the difference the proper tools can make. Anyway, moving on, the shaft that hold the laygear can now be pushed out from this end. It was a bit stuck at first and needed a little tap, but it wasn't too troublesome.

Laygear shaft.

Remember in Part 1, I locked the gearbox by engaging both reverse and 1st gear? I thought it was a good time now to unlock it and put it back into neutral. Once that was done, I lifted the laygear out.

Now the Oil Strainer and pickup pipe can be removed, not forgetting the copper thrust washers from the laygear also!

So far so good, but I fear that was the easy bit as now I needed to get the main shaft out. This is something I struggled with in the past, but help is at hand. Doing some research, I spotted a handy tip on this helpful page here on The Mini Forum. More on that later, but for now, I needed to get the 1st motion shaft and bearing out of the housing.

I did this by gently tapping on the other end of the shaft where the 1 1/2" bolt was sat, but to reach it I needed a length of broom handle that would clear the housing.

Tapping on the shaft, I could see the bearing at the other end slowly coming out! Until...

Pop!! The first Motion shaft is out!!

Centre Main Bearing
Well that wasn't too bad, but now for the tricky centre main bearing and that handy tip I picked up from The Mini Forum. The article shows a really easy way to get the centre bearing out, which involves making these simple wooden open washers...

I used one of these to make them if you were wondering.

Inserted as many as possible into this newly created gap here between the centre bearing and the 1st/2nd selector.

Like this...

Now using the broom handle and mallet, gently but firmly tap on here periodically adding extra wooden spacers as the gap gets bigger.

Until, the bearing pops out.


Main Shaft and Reverse Gear
Now the main shaft can easily lifted out of the box.

Leaving the gearbox looking kinda empty.

The last thing I removed was the reverse gear, which came free once its shaft was pushed out.

Reverse Gear
Nearly empty!

Checking Parts
All the parts that were taken out looked in very good reusable condition except for one. Unfortunately when I looked at the centre main bearing, one of the ball bearings looked totally knackered. It's a real shame as the rest of them look fine. I'm guessing that finding a single ball bearing will be difficult so I will probably need to source a whole replacement unit.

Glad I took the time to strip this gearbox now!!

Next Time
I think that's enough for one sitting, next time I will look at removing the gear selector forks and the bell crank release levers and that all starts by knocking out this pin.

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