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SirLanceUK

Cupola CVRT

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Hi,

As many of you will know I am in the process of rebuilding a CVRT Spartan. One of the features about the Spartan is the commanders Cupola. Like many that have sat around for years in all weathers my Cupola does not move. I have stripped down the winding mechanism and that is working correctly, took a great deal of blood sweat and tears but was little and easily fitted on my workbench. 

So the Cupola does not move, all the brakes have been removed so I am guessing water has got in and rust has seized the bearings. I have been through all the drawings I can find and nothing tells me how it works or is detailed enough to show my were the bearings are.

So how can the forum help... Does anyone know where I can get "detailed" drawings from or if there is a video somewhere showing how it should work, or even show me one working :)

in anticipation of your help

Lance

Front.jpg

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1 minute ago, sirhc said:

Lance,

do you have the Spartan ISPL?

https://www.greenmachinesurplus.com/cvrt-spartan-illustrated-parts-list-209-p.asp

You might find it useful..

Chris

D288DCFE-B6DA-4A4D-9F74-A8F0939F3EB5.jpeg

Thanks for that, believe it or not I have a document claiming to be that document but from Jul 05 but it does not display items 3 or 4 as the ball bearings its 3 and 4 are bearing rings but funny enough the diagram is on the same page....

D288DCFE-B6DA-4A4D-9F74-A8F0939F3EB5.thumb.jpeg.5dbc541ec0d6abd837a4fcc4e1a3405a[1].jpg

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The bearing ring probably went to being replaced as a complete unit rather than serviceable parts.

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Can you please send/ confirm to me the part number if you have it. and shame as it shows the ball bearings as different items, so raised my hopes that I might be able to do something

 

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If you take it to bits you should be able to strip it and grease the bearings. 

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1 minute ago, sirhc said:

If you take it to bits you should be able to strip it and grease the bearings. 

That's good news, I was slightly concerned when you said it was a replacement part

 

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i stripped and rebuilt a Striker cupola bearing - there really are A LOT of bearing rollers in there! I needed to get a bit creative and find a mechanised method of cleaning up the rollers as doing each one individually was not really viable - I found the most effective way was dumping all the rollers in a bucket of diesel with a handful of sand and stirring the whole lot with a paint stirrer attached to  drill. After about twenty minutes most of the rust was removed from them, then I washed them all and carefully re-assembled the bearing. 

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9 hours ago, Grasshopper said:

i stripped and rebuilt a Striker cupola bearing - there really are A LOT of bearing rollers in there! I needed to get a bit creative and find a mechanised method of cleaning up the rollers as doing each one individually was not really viable - I found the most effective way was dumping all the rollers in a bucket of diesel with a handful of sand and stirring the whole lot with a paint stirrer attached to  drill. After about twenty minutes most of the rust was removed from them, then I washed them all and carefully re-assembled the bearing. 

As you have done this before I hope you don't mind if I get stuck I ask you for help 

 

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So I have now arranged for fork lift to take the Cupola off on the 30th of November, I have asked lots of people to help should be an 8 man team, even had 1 volunteer who has done this before..... 

I will update the forum as to what happens, hopefully a cupola that spins like a very spinny thing.

 

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After removing all the bolts (very easy, think someone had had a go already) I got up today to see if the Cuopola would come off on the 30th or needed some help (very large hammer or heating). To my surprise it lifted straight up, their is some sort of laminated ring on top of the body that is cracked (dont think i did it)  but the body under the ring is rusty so needs treating before I replace the cupola....

Now here is a question does that ring need replacing or is it there as a "seal" against water... anyone know?

My plan is when the cupola is lifted clear to treat the rust and make a "gasket" to put the cupola back on... Unless someone knows different

 

Edited by SirLanceUK
Should learn to type and spell

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Fingers crossed my local farmer is coming around tomorrow to lift off the cuploa. Then I hope to take a few pictures and see what we will see.

Got a few old hands with MV's coming round to offer advice, assistance and maybe a beer

Hopefully start updating from Tuesday

 

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Well the farmer turned up and 10 mins later the cupola was off and being transported to my garage

Then with 4 burly men and me I was able to get it upside down

 

Ring3.thumb.jpg.8bd70c224a7bfaddfcccaf8df5bd6b77.jpg

You can see things are rusty, we sat around having a tea then started to undo some bolts

Ring2.thumb.jpg.0fbc71f9933429111db7ba2c3d790595.jpg

Much debate about how it works and I didn't tell them I had a diagram so knew a little

More Allen bolts removed and MORE rust uncovered

 

Ring4.thumb.jpg.587fabedd491195ed0c9e64cd3e5a0a5.jpg

Interesting arrangement of bearings and shims all covered in rust. Still I had nothing to do for the next couple of weeks. And for those that are interested the order is Shim-Bearing facing up-Shim-Bearing laying sideways-Shim repeat lots of times. and after trapping my fingers the bearing and shims just lift out :)

 

 

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witham sold off quite a few complete very good condition cupolas from the scimitar 2 build program-think they sold for around the £200 mark

 

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2 minutes ago, terryb said:

witham sold off quite a few complete very good condition cupolas from the scimitar 2 build program-think they sold for around the £200 mark

 

Recently? I have not seen anything 

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58 minutes ago, SirLanceUK said:

Recently? I have not seen anything 

That was around 2012. 

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Andrew Baker has loads of cupolas lying around, although I'd guess most of them are in no better condition than what you have.

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After extracting all the "bearings" turns out they are cylinders 12mm tall and 12mm in Diameter. They are placed one facing up and one facing out. Between each cylinder appears to be a metal disk (shim) covered in "plastic". The track where they run is very pitted on one side with rust, I have started to wire brush the track to see how smooth I can get it. Also will be reading up on how I can treat the track once I have removed the rust as I have a feeling it wont be a "smooth" surface. 

So looks like I will getting some new Cylinders as some are completely flat spotted and some shims 3mm x 11mm have shed there plastic coatings... Gotta a feeling this may take some timeshims.thumb.jpg.ebc0db413ae2c3b7e4f2d0abc8b8a732.jpg

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Posted (edited)

Help, there is a mico switch on a plunger that follows the cupola rings, what does it do?

On the upper most ring there is as raised section that moves a plunger up and down as the ring rotates. The plunger moving up and down actuates a micro switch which has 2 wires going in to a plug. After looking through the several wiring diagrams for the cupola of the all the variants I couldn't find what it is used for on my model.

So Forum  what does it do (remember it's a Spartan)

As an update, I have removed the rust from the cupola, treated the now exposed metal and ordered a ton of graphite grease to pack the bearings in. Putting it back together starts tomorrow

you can see the plunger in the bottom right corner inside a brass bush

removed.jpg

Edited by SirLanceUK
wanted to put a picture in

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The next step on the journey.. After putting the first ring on I placed 147 bearings along with their spacers - I have used 3 ton of graphite grease to pack out the bearings and fitted the shim rings then the next ring. Installed the Allen bolts to secure the rings together. Placed the next ring on top of the other rings, disaster I can only find 2 out of the 3 bolts.

At this point I will claim that only 7 of the 8 bolts where ever there. New bolt ordered and duly arrived, all 3 bolts fitted in to the last ring, all is secure. 

Does the ring revolve, spin like a spinney thing...  NO... However with a large screwdriver and a little effort it moves.....

Now to fit it back on the Body

 

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I put the winding handle on to Cupola and despite it being upside down it rotated. It's never going to win an fasted spinning thing but I was able to turn it with one hand. As I couldn't move it at all when I brought it this is a win. Looks like the 16th is the day it goes back on to the body... 

Still don't know what the microswitch does but it operates when the cupola is forward facing, maybe it is a cut out so you can only fire forward.... If I do find out I will let all know

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"Still don't know what the microswitch does but it operates when the cupola is forward facing, maybe it is a cut out so you can only fire forward.... If I do find out I will let all know "

Just letting you know - talking to a Striker owner (he knows who he is) reading the prf the micro switch is a trigger inhibitor and stops the GPMG from shooting in a rear ward direction taking out the rear equipment and aerials.

Not a problem I think I will ever have, but knowledge I am glad I have ...

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Following this with interest as I have 2 Spartans and a Striker to do this job on!  As an aside, I have exactly the same T handle hex set as you!

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