Orv gearbox- 28mm shaft???

[Terz1 734]

Hi everyone. I'm rebuilding a ORV gearbox from a vintage mud blaster. I've stripped everything down and I was just starting the rebuild with bearings etc when I noticed in the manual it should have a 2 x 28mm shaft that goes through the 'short joint shafts' on either side of the gearbox. I know it didn't have one when I took it apart as each short joint shaft hole was filled with grease, so much in fact it was hard to tell if it had a hole in them at all.

My question is, is this essential in running the car? It's a vintage mud blaster like I mentioned and the tyres had a lot of wear and the body had a good few battle scars and it looked like it had had a busy life so it has been run without this shaft. Throughout the strip down I noticed whoever had built it had paid care and attention, with neatly tied up wiring and all correct screws used etc except for this missing shaft in the gearbox. Would it have been deliberately omitted?

If it is really an essential part would it be in the re-re parts bag in the monster beetle or blackfoot? I know they made some changes in that area. If not I'm thinking of getting some 2mm rod and cutting to size. Any ideas on this are really welcome. Any ORV masters out there?   Thanks.

 

This is the missing part circled in red....

 

 

*Thanks to CompetionX for the above picture from their really useful online manuals 

[MadInventor 2927]

The diff will be more prone to shredding without it. I doubt it would have been deliberately omitted. On later Tamiya model the 2mm pin is fixed into one of the drive cups to prevent loss or accidently not including it in the build, so I would say it is essential. I would also point out that the genuine ones are made from good quality steel which does not bend readily, so just putting some cheap 2mm dia. wire in may not help. I would try and source an original Tamiya pin, even if it's pulled from another cars joint cup set.

[Static Age 60]

As said above, the diff will fail quickly without it.

If you do make one up then use hardened steel.

[Terz1 734]

Thanks for the advice. So from that I definitely need to get one of these shafts. With the kit being so old i think it's going to be a bit of a challenge , Unless I bought a orv rolling chassis and hope there's one in the gearbox. Having a bit of trouble finding a UK supplier of hardened 2mm rod too. I found some on ebay but most seem to be China or pretending to be in the UK but they are actually in China.

Am I on the right path with something like this?

https://www.ebay.co.uk/itm/K10-Solid-Cemented-Carbide-Tungsten-Steel-Round-Bar-Rods-L-10cm-D-2-10mm/352373373571?hash=item520b16fa83:m:m0FUeKQ3mlr170fvxk9z_rw:rk:4:pf:0&var=621737337226

I even checked the other ORV kits like the frog and brat as well as the re-re monster beetle and blackfoot but they seem to have some updates in this area and use a 5mm shaft instead of the 2mm version. 

Another option I've thought of is buying the re-re parts bag and building a new gearbox, just thoughts at the moment. 

[ruebiracer 617]

11 minutes ago, Terz1 said:

Thanks for the advice. So from that I definitely need to get one of these shafts. With the kit being so old i think it's going to be a bit of a challenge , Unless I bought a orv rolling chassis and hope there's one in the gearbox. Having a bit of trouble finding a UK supplier of hardened 2mm rod too. I found some on ebay but most seem to be China or pretending to be in the UK but they are actually in China.

Am I on the right path with something like this?

https://www.ebay.co.uk/itm/K10-Solid-Cemented-Carbide-Tungsten-Steel-Round-Bar-Rods-L-10cm-D-2-10mm/352373373571?hash=item520b16fa83:m:m0FUeKQ3mlr170fvxk9z_rw:rk:4:pf:0&var=621737337226

I even checked the other ORV kits like the frog and brat as well as the re-re monster beetle and blackfoot but they seem to have some updates in this area and use a 5mm shaft instead of the 2mm version. 

Another option I've thought of is buying the re-re parts bag and building a new gearbox, just thoughts at the moment. 

The link looks o.k, for sure you can use something like this! If the rest of your gearbox and drive shafts look o.k., keep them. Re Re parts are not really better. Pack the diff with Tamiya AW grease, helps to prevent wear and gives some locking effect for the diff...

[Terz1 734]

Thanks Ruebiracer  . I'll order some this week. Some descriptions said mild steel but don't think that would be the best. It'll come from China but I've ordered stuff from there before so all's good. Just have to wait a bit longer sometimes.

[svenb 1718]

Could you use the shaft from a regular set of diff cups?  ie separate in a vice.

[svenb 1718]

I now see madInventor has already mentioned this🙄

I have a pair of cups you can have to pull the shaft!

[Frog Jumper 946]

I *think* you can find that part in a vintage Blackfoot Metal Parts Bag (Tamiya #9405267), or via MRC (MRC #X9955)...

https://picclick.com/Tamiya-Blackfoot-Monster-Beetle-Metal-Parts-Bag-Original-361925026618.html#&gid=1&pid=1

Terry

[Static Age 60]

I needed a hard to find gearbox shaft once. I cut the shank off of a drill bit.

[IBIFTKH 1349]

Bigwig re-re diff also uses a 2x28mm shaft in the centre.

[Terz1 734]

On 11/6/2018 at 10:41 PM, svenb said:

I now see madInventor has already mentioned this🙄

I have a pair of cups you can have to pull the shaft!

Thanks for the offer SvenB, I so apprciate you offering a pair of cups . I've ordered a few things which I mention later.

 

19 hours ago, Frog Jumper said:

I *think* you can find that part in a vintage Blackfoot Metal Parts Bag (Tamiya #9405267), or via MRC (MRC #X9955)...

https://picclick.com/Tamiya-Blackfoot-Monster-Beetle-Metal-Parts-Bag-Original-361925026618.html#&gid=1&pid=1

Terry

I checked out this link. Amazing that some of these vintage parts are still available. They seem to be mostly in the US and I think that particular seller is away at the moment. It looks a great site and I'll definitely look there in the future 

 

10 hours ago, Static Age said:

I needed a hard to find gearbox shaft once. I cut the shank off of a drill bit.

I've been looking at all sorts I could use. That's one I hadn't thought of though. Good find!

 

10 hours ago, IBIFTKH said:

Bigwig re-re diff also uses a 2x28mm shaft in the centre.

You found one! 

 

I can't thank you all enough. I had ordered the 2mm rod so that will get here when it gets here from China. I've just this moment ordered the re-re bigwig parts bag 'A'. It's just the thing I needed having the 2 x 28mm shaft and other little goodies I'll no doubt use in the future and will be here before weekend.  The Mud blaster can now be finished! 

Again, thanks, you guys have so much knowledge about tamiya it's amazing. 

[Hobgoblin 994]

A bit of 2mm silversteel should be good if you haven't already sorted it or want a cheap temp fix. Ground round for a bearing fit and decently hard. Plus it will be about £2 for a 4" length.