74 replies to this topic

[Spider]

Well, I should kick off by say this is not for me! This is actually the repair of a Gearbox for a Moke known as Quadra. suffered a major failure at an outing a few years back now. I undertook this re-design / repair back in early 2012.

 

It was originally made by a guy in our club, Max Kinsmore, back in the late 70's. The Bevel Gears used in this one are actually from a Prototype that was Made by our local Leyland Factory as they were considering putting these in to production - another story for another time!   I digress - This Leyland Prototype design is actually based upon the Leyland ST Mini, which in turn was based on one of Issigonis's Prototype Single Engine, 4WD Mokes of the early 60's.

 

A Friend of mine now owns the Moke, which is not a factory car, but does have a few factory parts in it.

This was the gearcase from it, after I'd stripped most of it




When it was stripped down, the diff pinion was found in a hundred pieces. Not the first one I've seen like this



but closer inspection of the gearcase show a LOT of other problems, most of them old, but signs that this design was not up to the task



the case and the diff cap were fund FULL of cracks and other damage from previous failures. The diff cap hardly even lined up, so no wonder it leaked oil.

It was off to the drawing board for a few weeks. I came up with a solution and design to overcome all it problems and (hopefully!) make it un-breakable.

So, next thing was to start making all the bits

First was the diff hemispehere. The stock 2 sun gear designs are hopeless, so I made a 4 sun gear, X-pin type









I had to make a special tool to cut the thrust faces for the sun gears



trial fit to check it's shape - perfect!



now to cut them for real



starting to take shape





next, I had to machine up a crown wheel, this is another weak point in the stock mokes and this one is no exception



then fit the bevel gear to it



then the next major problem part, the diff cap. We got a new gearcase and I had to measure up super-accurately the existing diff cap



I machined up a new one from a soild billet. Here, I'm just starting to face it, to get it 100% square and flat



then next was the bearing tunnel. to get this perfectly round and on size, I had to bolt it up to another piece the same. This is the start of something BIG



back in the lathe



boring it



perfect!



pitch out and drill all the holes. This needed to be super-accurate (I was working to +/- 0.005 mm!)



fits and lines up! Bonus!



next, some relieving of the gearcase as the new diff is bigger



trail fitting the diff



yippie!

next, I had to measure exatly where the output pinion needed to be for the RWD part



then, I could machine out the guts of the cap



look it fits!



then face back the cap to get it all lined up with the gearcase



planing the back of the diff cap at an angle, to get the output pinion facing the right way



boring the hole for the pinion



just about there!



there, all major machining done!



all that's left now is the big clean up and assembly!

 

To be continued.

[Spider]

Here's some pics of the original proto-type Crownwheel



There's the part number. Anyone got a reference to it?



You can see that this one is missing teeth, but also, that it has the bearing mount. Oddly, there are only 3 bolt holes for the hemisphere, I have no idea what the score was on that.

The ratio of the bevel gearset is 2.1:1 so way too tall to be a diff from any other vehicle that I know of. I am in no doubt that these are genuine Moke ones.



On the Left is the new Crownwheel and the one that was fitted on the right (I have machined the bevel gear out of it). I think the new one will be considerably stronger!



And the new Pinion too (on the left).

Some pics of the diff cap that was on it





This was a Remote Shift cap on a Rod Shift Box!!!!  I doubt that this was done by the factory, I think this was some of Max's handywork. The alignment was unbelievably poor. I have no idea how it held oil. You can see some cracks and gouges from previous learning experiences.

I did look long and hard at welding a flange to the back of the shock Rod Shift Cap, but there is next to no meat in it. All the stock one really has to do is keep oil in, this one does a little more 

This is the Factory proto-type hemisphere



You can see the chatter marks from the bevel gear teeth! This was because the whole assembly was parting company (from the stripping threads) and effectively bending. I have a black and white pic of the factory units I'll throw up a little latter (when I dig it out!).

Edited by Moke Spider, 10 December 2014 - 08:57 AM.

[Spider]

Some progress

The Gear Shifter set up had something missing! It had no steady on it and so when accellerating or decellerating it was prone to jumping out of gear



So, I had to nut out a steady. Not having the car here made it had to make decisions as I didn't know what was where and what clearances I'd have.

So I brazed a bracket to the output pinion bearing carrier



Then bent up a suitable rod



I've also made up some spacers and so now ALL machining and fabrication is done!

Yipppeeee - it felt like a marathon!

So this afternoon, I tubbed everything up



Does anyone know where all this stuff goes 



I've started on the assembly. More to come 

Edited by Moke Spider, 10 December 2014 - 09:17 AM.

[Spider]

Really taking some shape here



Hopefully I'll have it fully assembled today. I've also now got the front Subframe here, so I can trial fit it and check that it actually fits - that could be embarrassing!

 

Here's a couple of shots of the subframe





The spacers on top measure a total of 31 mm. I'm not entirely sure why these are needed, but it maybe to get enough room between the tunnel in the floor pan and the output rear facing drive. The pics of have of the factory ones didn't seem to need any spacing. I might get a better idea later today when I trail fit them together.

 

Tada - it's FINISHED  (much to my good wife's relief)

[Spider]

Following this repair / rebuild, the owner of the car in to which it belongs undertook a full restoration of the whole car, it's now been on the road for about a year now, he's commented that for the first time in his ownership it doesn't leak oil (funny about that!) and it's surprisingly so much quieter than it's ever been, all he hears now are the tyres and some exhaust note!

[steve m]

Can,t see any pictures

[Spider]

Hmm,,,,, they are on photobucket, sometimes they are slow to load, just give it a few moments, if they don't pop up, I'll re-insert the images.

[Carlos W]

Phenomenal work.

[Carlos W]

Hmm,,,,, they are on photobucket, sometimes they are slow to load, just give it a few moments, if they don't pop up, I'll re-insert the images.

 

I couldn't see them at first, but can now

[Guess-Works.com]

Fantastic !

[cal844]

Epic and expensive work!!

[BritishRacingGreen]

Unbelievable... You didn't make two did you? 😜

[brownspeed]

Bloody Hell! I bet that was a busy couple of days!!

love that workshop facility

[Tahiti Joe]

Fantastic work, I've dreamt about this sorta thing for mine for a while now. Would make the low traction situations I regularly find myself in a lot easier to maneuver out of...! If you'd ever be interested in making another id be seriously interested.

[coopdog]

That is amazing work

Never better than making something from scratch and watching it take shape!