Madinventor Juggernaut 2 rebuild

[MadInventor 3884]

So I picked up this Juggernaut 2 off a TC member about 10 years ago. It has been a semi regular runner since then, with a an old parma 50's van shell. Not long ago I binned the leaf springs in favour of a 4 link system using TXT-1 axle guards on the front, and a guard of my own design on the back. Anyhow, the TXT guards failed on a slight jump, and given I didn't want to make more aluminium guards for the front and wanted to get it back on the road, so I put the leaf springs back on the front for the time being. This thread is going be about a rolling update to it. So first off, here's the TXT guards that failed:

This is the fourth one I've broken now, so I suspect it's either brittle old plastic, or they're just not up to the job.

2 things I've done with this, first of all I'd been running the truck with TXT-1 stub axles to widen the track, and TXT-1 wheels with Jugg tires glued on. A while ago I wanted to fit clod tires on it to improve the handling, bought the tires, then found out I'd glued on the Jugg tires to the TXT-1 wheels. The only other wheels I had were some old clod wheels, but of course I can't use these with TXT-1 hubs as the drive lugs are too small, and it's impossible to find TXT-1 wheels for sale anywhere now. I went back to the Jugg stub axles, but then the rear 4 link suspension fouled on the tires, and the clod tires fouled on the suspension links at the front. I then had the brainwave that I'd got some Chinese alloy wheel hubs on the truck, so I put them on the mill and drilled holes for the clod wheels between the holes for the TXT-1 wheels, there are just some days when I love having the DRO (Before on the left, after on the right)

This fixed the front end, allowing me to use TXT-1 stub axles with clod wheels.

As for the rear end, I made 2 new drive shafts. With the rear steering locked out, there wasn't really a need for steerable axles, so I cut the dogbones off 2 clod axles (1 was already broken), and made 2 extension pieces which I sleeved and attached to the clod axles with Loctite gear locker compound:

I also made a couple of new hubs to fit to the new axles, and some sleeves to stop the roller bearings falling out of the ends of the axles.

Now wouldn't it be nice if Tamiya could parcel this little lot into a hop up package (With one 1piece axles obviously, these would be cheaper to make than a dogbone shaft and a drive cup shaft), along with some extended TXT axle tubes that don't need the steerable hub fitted on the end. Just a straight axle. They could even do the same for the clod, just a few metal parts and a couple of longer axle tubes. It would then make a really neat solution for the those many owners out there that don't want 4 wheel steering, and want to make their clod buster or Jugg track that little bit wider. I've used flats on the shafts and grub screws to attach the hubs, but Tamiya could easily put a spline on the end to make it compatible with the existing kit pieces.

Fitted into the axle

Semi assembled, Wouldn't this look better if the square axle tubes just extended to the wheel hub

Sleeves fitted to the ends of the axles to stop the bearings coming loose

More to follow....

 

[ACCEL 2014]

YES!

         &

 

 

[MadInventor 3884]

A little bit more to report:

Made two of these, bumper mounts integrated into the front spring hanger. Brass sleeve is to prevent the step pin that holds the leaf hangers from wearing the aluminium.

Painted and fitted.

I'm now in the process of machining a bumper from a large lump of aluminium.

[Grumpy pants 4484]

I can’t remember ever having seen a Jug rebuild in my time on TC.

Will be watching this thread with great interest 😊

[MadInventor 3884]

1 hour ago, Grumpy pants said:

I can’t remember ever having seen a Jug rebuild in my time on TC.

Will be watching this thread with great interest 😊

That means I've got to come up with something good now .....

[MadInventor 3884]

Machining a new bumper from an aluminium plate.

This is the back side pocketed out to save weight:

Polished:

Fitted with a Wild Willy winch:

With a bodyshell dropped on. It won't be this one as it's off my sons clod, but I will be looking to fit a clodbuster shell onto it.

 

[Aerobert 2136]

That's awesome!

A milling machine is something that I also want. I have in fact no idea have to work with it, but I would like to have one. Until then I will go on with saw and file. 

[didcos 37]

Nice job!

Regarding the axle guards, it's just a bad design. Mine have cracks at the exact same spot. I stopped driving before completely breaking them and reinforced them with CNC-made small aluminium plates on each side, using metric screws through the 3 available holes.

[MadInventor 3884]

Underslung lightbar so it doesn't get mashed in a rollover or front ender. Cut 2 lights of a 5 bar light, and drilled 2 holes in the bumper brackets to mount it.

 

 

[MadInventor 3884]

I've spent some more time on the mill this week, I made 4 of these brackets

So that I could add an aluminium plate low down in the chassis.

with room to put the ESC and receiver at the front of the truck.

There would normally have been a moulded plate there to mount an MSC on, but this allows me to tuck the receiver and ESC down in the front of the truck, which will keep nearly all the wiring at the front of the truck. I can use a short run of wires from the RX to the LED bar to power it, and I have also been able to mount the on / off switch on the bumper close to the winch, which makes it easily accessible, and it doesn't look too out of place. It was surprising how long it took to make the brackets to mount the plate on, each one took well over an hour. In hindsight I should probably have asked a friend to 3D print them for me, but the aluminium will be stronger.

So, things still to do:

1.Wire up the lightbar. 

2. Shorten the motor leads to tidy up the wiring

3. Clean up the old radio / battery tray.

4. Convert the axle input from 5mm to 6mm so I can use traxxas drive shafts. This would be easy if the TXT parts were available, but they're not so I'm going to have to improvise. I also need to ID one of the traxxas drive shafts I used on the war rig, as I think it would ideal for this truck, but can't remember which traxxas model it came from (Facepalm!)

5. Take the gearbox apart and fit one of my custom output shafts that is longer than the standard tamiya items, and allows easy fitment of traxxas driveshafts. There is already a TXT-1 output shaft fitted, so I have some hybrid drive shafts in at the moment, which are made up from both TXT-1 and Juggernaut 2 drive shafts.

6. Build body mount for the Clod shell. I want to use the existing body holes to align the body, but have it held on underneath with velcro so I don't need to use body pins.

7. Get a clod shell, as the one in the photos has to go back on my sons Clod.

8. Decide what to do with the suspension, whether to go back to all leafs, which looks the best, but I'll have to find another use for the rear axle guard I made, or use a combo of leafs / 4 links, or go full 4 link. Decisions decisions........

 

 

[MadInventor 3884]

I've now wired up the LED lamps with a 100ohm resistor, so the next job is transmission mods. The Juggernaut came with a 5mm diameter output shaft, but the one I got was a 6mm TXT-1 item. I think the gearbox got mixed up in someone's parts bin, as the axles still had the original Juggernaut 5mm input shafts. I ended up making up some hybrid drive shafts that were part TXT-1 shafts, part Juggernaut items. Now these shafts were made from brass, but it might as well be cheese for how long they last. I'd fitted mine with some home made pins which were hardened steel instead of brass, which improved the situation, but the outer yokes are still brass and starting to show signs of wear. So today I ordered some traxxas slayer pro drive shafts to replace these, so I now got to make them fit. As their diameter is bigger than the tamiya shafts, I've had to make a new output shaft for the transmission. See pic below.

The lower part is the standard tamiya item, with an aluminium hex driven by a spline and held in place with circlips. The upper one is the one I'd made. The hex is steel (Machined from round bar) and attached to the drive shaft by drilling and pinning (With a tamiya 12mm hex axle pin), and also glued on with the Loctite gear locker. Only 1 circlip is then needed to attach the gear to the shaft. The shaft is also longer to allow the traxxas drive shafts to bolt straight on without modification.

Next job now is to modify the gearbox input shafts to be 6mm instead of 5mm. I would just use TXT-1 items, but there's no stock available anywhere, so I'll have to improvise. More on that later....

[MadInventor 3884]

So I'm waiting on my new traxxas drive shafts to turn up, so have started work on the new body mounts:

Added some high density foam to help absorb shocks. I still need to glue it on and attach velcro to the foam and the shell. I can then use the pins to align the shell on the truck, but it's held on with velcro and so body pins are not required.

Body looks ok, is a bit lower than on the original Clod buster. Wheelbase is 5mm longer on Jugg2 than Clod, which is not really visible.

Still got a problem with the steering. Even with TXT-1 axles, the Clod wheels have a slightly smaller offset than the TXT-1 wheels, and the tires catch on the axle guards. This means I'm going to have to go back to using 4 links on the front so I can fit a narrower axle guard. I just need to make sure it's suitably beefy so I don't get the same problem I have with the tamiya plastic parts.

[ACCEL 2014]

Mad Inventor the Real Power House.

Looks so grand.

 

[MadInventor 3884]

 

So a little bit more movement on this project.

I found the gearbox casing was badly cracked, so bit the bullet and ordered a new one from Ebay. It arrived yesterday, and so today I dismantled the gearbox and re-assembled it into the new casing. I found one of 1160 bearings was rough so replaced both of them with new. Also, rather than attaching the motor plate with self tappers, I drilled out the holes with a 2.5mm drill, and then tapped the holes with an M3 tap. The motor plate was then fitted machine screws (tamiya M3x12), to replicate the look of the original screws. I also tapped the 4 holes that are used to attach the gearbox to the chassis with and re-attached with socket cap screws, to match those I used to hold the side plates on with. No pictures, as it just looks like a standard gearbox.

My new traxxas slayer pro drive shafts turned up. I got  a pack of 4 (the upper shaft), and made 2 of the lower shafts with the bits. These are ideal for my application and will hopefully require no further modification to fit.

A while ago I bought a bag of TXT-1 ball joints, as I'd previously had the Clod / Jugg ball joints shear off. I drilled out the holes on the suspension brackets and the ball joints are a perfect fit, and will be stronger than the brass items. The top mounts I also drilled out the axle guard mount holes, as I am going to fit my own custom axle guards.

I also completed the new underguard today. This replaces the 2 metal plates tamiya used to hold the leaf spring shackles in place. 1 piece of metal does the job and effectively protects the bottom of the axle in the process.

 

 

[GTodd 1347]

Very nice build. I'd love to purchase a Juggernaut but the prices they now demand are insane.  It's be awesome if Tamiya did a Jugg 3 Rere kind of thing, but with the TXT2 still out I'd doubt it'd happen. 

[MadInventor 3884]

18 hours ago, GTodd said:

Very nice build. I'd love to purchase a Juggernaut but the prices they now demand are insane.  It's be awesome if Tamiya did a Jugg 3 Rere kind of thing, but with the TXT2 still out I'd doubt it'd happen. 

Well, this is kind of what I'm working on now. My idea for what the next fixed axle Tamiya monster truck should be.

[Saito2 6686]

Beautiful work, as always, @MadInventor. Out of curiosity, never having seen one in the flesh, how do Juggernaut leaf spring react/perform? Are they stiff and somewhat travel-limited like a stock Clod with the stock travel-limiting rubber tubing installed? 

[MadInventor 3884]

5 hours ago, Saito2 said:

Beautiful work, as always, @MadInventor. Out of curiosity, never having seen one in the flesh, how do Juggernaut leaf spring react/perform? Are they stiff and somewhat travel-limited like a stock Clod with the stock travel-limiting rubber tubing installed? 

That's pretty much it. They're very stiff and limit the suspension travel, but also the torque twist. My plan is to put leaf springs on the back to stop the torque twist, and put a 4 link system on the front to allow some flexiblity for climbing over obstacles and rough ground. Hopefully it will be a good compromise of both systems.

[MadInventor 3884]

Made some more progress yesterday. Finally finished off the new input shaft for the rear axle, and was able to reassemble the rear suspension.

This shows the new shaft in the top of the photo (The original one is below it.. It's made from a piece of 6mm stainless steel, turned down to 5mm where necessary to avoid bits of plastic in the axle housing. I've drilled the splines out of the brass bevel gear and loctited it onto the shaft.  I also had to make a 0.5mm thick shim to space out the gear from the bearing it pushes against.

I like this design as 

1. It removes the slop of the splines.

2. The drive shaft no longer has a weak point where the slot is made for the e clip to fit on the original.

3. I can now fit drive shafts designed to fit on a 6mm shaft

Turned down to 5mm. I retained a bit of 6mm on the end for an 1160 bearing to fit on, as I was not confident in getting a perfect fit turning down the shaft for a 1150 bearing.

Assembled with the shim fitted between the gear and the bearing

Fitted in the gearbox. Note the traxxas drive shaft

With the lid on. I made the shaft slightly longer than it needs to be as I overestimated the clearance required. The one for the front axle will be 1mm shorter.

I moved to using these high lift dampers on the truck ages ago. They look so much better than the stand pogo sticks, and more realistic than coil overs with the leaf springs already fitted. They almost look like they were made for the truck, and are a perfect fit.

I've gone back to using standard chassis side plates and brass ball joints. I polished the ball joints in the lathe before fitting, and have added extra screws in the all spare holes to ensure the chassis hold together ok.

 

New Traxxas drive shaft fitted, as viewed from below. It's a perfect fit and required no modification. I bought a pack of 4 shafts (Traxxas Slayer Pro) so that I have yokes for both ends, and some spares (Although I've never managed to break a Traxxas drive shaft yet). The pack was cheaper than buying 2 of tamiya's cheese specials, traxxas should really sell them as a hop up for the TXT-1 

[MadInventor 3884]

Got the front axle on, configured for behind the axle steering, with stock components would you believe .....

Just misses Traxxas driveshaft on full lock. Stock tamiya UJ is even smaller.

Simply turned the Juggernaut 2 steering post round, and it's perfect for a BTA setup

Modified input shaft is 1mm shorter than the rear axle one, and is now a neat fit, but still with plenty of clearance

Truck with axle fitted and temporary 90mm shocks. The aim for the finished model is to have Hi Lift shocks on the front, with hornet front springs inside them to stiffen them up to take the weight of the front of the truck. (In hindsight I should have probably used a stock clod front bumper)

Upper 4 link mounts mimic the Juggernaut leaf spring layout, plus I added 2 more in case I ended up fitting coil over shocks on the front instead of the high lift shocks. I'm really liking the new axle guard. it's made from 2mm thick steel plate, and leaves about 3mm of space in front of the axle. Lower links mount on to it so no danger of break the lower link mount now.

 

Steering track rods just miss the 4 links, but they do miss

 

[MadInventor 3884]

Latest update, I've rebuilt the rear underguard to have the steering hubs inboard rather than outboard, which allow for wrapping the axle guard closer to the axle. I also made the axle guard taller at the rear to provide a vertical surface in case I want to mount a tow bar (That's what the 2 holes are for.

[MadInventor 3884]

Another update, I ran the truck back in January and found 2 things:

1. The turning circle was too wide for my taste with 2 wheels steering only.

2. The home made input shafts with the brass gears loctited to them couldn't take the power of the 3S LiPo. Well, one failed and then I cleaned it and re-glued it and it held, then the other one failed as well. 

So I then had a 6 month wait to get some input shafts, as the only ones I could find on the internet were in Germany and the model shop in who had them wouldn't send them unless I spent over £140, thanks to the new Brexit regulations. Thankfully Tony' s Tamiya on Ebay sold me some TXT-1 parts a few weeks ago and I was able to get a bit closer to completion.

In the interim I managed to buy a set of second hand High Lift shock absorbers for the front suspension. These were cleaned up and I polished the piston in the lathe to remove the light scratching on them. I removed the stock springs and put in 4 hornet front springs, which were marginally stiffer. 4 of these is enough to hold up the front of the truck (Even with the aluminium bumper) whilst leaving the front suspension very supple.

(4 links on the front, the only springs are inside the high lift shocks, rears are more like original Jugg 2 suspension with leaf springs)

I glued on high density foam and velco onto the body mount plates. I velcro holds the bodyshell on, and the foam gives a bit cushioning if I roll the truck.

Once I got it up and running I decided to revert it back to 4 wheel steering, but wanted the rear end to have 'behind the axle' steering, the same as the front. So I used the mirrored the system I used on the front, the only problem being the steering pivot was now on the opposite side to the steering servo mounted up in the chassis. To get around this, I used one of the bendy track rods from a high lift, with a small aluminium extension to allow it to reach to steering servo mounted up in the chassis.  

Steering at the front.

Steering at the back

High lift track rod used to connect rear steering

Rear steering pivot

With the shell on.

 

[Unknown Driver 262]

I still have a TXT-1 that's one of my favorite runners - LOVE seeing the work you're putting into this truck. If you ever offer your designs for sale, I'd be interested