MST MTX-1 4WD TH-1 Body

[alvinlwh 5895]

My TA-02 budget rally build had grinded to a halt as I made a mistake with the paint and ran out. So while waiting for a delivery (thanks to @ad456), I decided to move onto the next on my build list, the MST MTX-1 4WD.

Some specs of the vehicle on the box. 

@Mad Ax had done one and I will be checking over his thread to make life easier for myself. 😉

Starting off, the unboxing which he did not do. 

The strong box fits the body more or less exactly. Wheels with tyres are placed into the body while parts are split into two bags and placed at the void where the bed and hood of the truck is. This allows for a really compact and tight packaging. 

[alvinlwh 5895]

This is my second MST build, the first being a TCR-M, so I am familiar with their instructions (with the spelling mistakes) and packaging, everything are packed into bags which corresponding with the steps. 

It comes with a nice little tools bag, but I have better Alan keys of my own. 

Most parts are not in trees and screws are sorted out into their own sections in a bag. Best thing? Bearings and steel pinion included as standard. 

Bearings receive a drop or two of YR bearing oil before installation. 

Now onto the step by step. 

[alvinlwh 5895]

Bag 1 & 2

Part 1 - Transmission 

Step 1 - Deceleration gear assembly 

Not sure why is this called that, but I believe this is the final drive gear. The gear and holder is an all plastic affair but aftermarket metal ones can be bought. 

[alvinlwh 5895]

Step 2 - Deceleration gear assembly 

Confusingly, Step 2 has the same title as step 1 when it is more of inserting gears into the gear box. The instruction for the counter/idle gear is wrong. Luckily, it is just a 4mm e clip to remove. 

They are greased up with the included "black grease", not sure what it really is. 

[alvinlwh 5895]

Step 3 - Attaching motor mount 

I will be using a brand new Tamiya M3 thread former on this build. Ironic that it's first use will not be in a Tamiya kit. 

There are quite a few metal to metal screw joints here and I used threadlock on them. 

Instructions are slightly confusing here so looking at the finished article in Step 4 helps. The shafts spins really freely after sealing the gearbox half's together. 

[alvinlwh 5895]

Step 4 - Dust cover assembly 

Again, the screws goes into metal, so threadlock was used although probably unnecessary. 

[alvinlwh 5895]

Step 5 - Attaching motor 

This step was skipped as the motors have not arrived yet. Also, I am undecided on which motor to use yet.

Point to note is that a 24T 0.6mod steel pinion is included as standard. 

[alvinlwh 5895]

Step 6 - Attaching spur gear 

The spur gear has these blue rubber blocks to take up the shock. 

[alvinlwh 5895]

Step 7 - Attaching dust cover

The cover was lightly attached first as it need to come off along with the spur when the motor arrives. 

And this is the end of Part 1, Bags 1 & 2.

[alvinlwh 5895]

Bag 3

Part 2 - Links

Step 1 - Upper & Lower link assembly 

Step 2 - Servo link assembly 

Step 3 - Steering link assembly 

Even though it is broken down to three steps it is just basically a load of pain time. 

At first I was confused as there are no length given for the finished article but looking at later steps, it seems that what I need to do is just to screw them all the way down. Now these plastic bits are a known weak point on this chassis, so some Aliexpress all metal turnbuckles may be considered in the future. 

Anyway, that is the lot done, with sore fingers. 

Also, unlike my previous MST kits, there are left over parts in this bag to be used in future steps. 

[alvinlwh 5895]

Bag 4, 5, 6, 7

Part 3 Frame Rail

This is a major stage consisting multiple bags (even Bag 13 is involved) spanning a few evenings to complete. The chassis halves comes in their own unnumbered bag as well. 

 

[alvinlwh 5895]

Step 1 - Upper & Lower link assembly 

This involves fitting the links to the chassis halves, they seem the same front and back. 

However care is needed as there are multiple holes on the frame halves and MST's instructions are not as clear as Tamiya's. 

The links do not move as freely as I like, probably due to the plastic balls, which I may change for metal in the future. 

[alvinlwh 5895]

Step 2 - Frame Rail assembly 

This is a major step consisting of multiple sub steps. 

Threads are formed in all screw holes using the Tamiya M3 thread former tool. 

Great care is needed as again, there are multiple holes along with some slightly unclear instructions. 

[alvinlwh 5895]

Step 4 (where is 3?)-Attaching wheelie bar

I believe the missing Step 3 is the actual building of the wheelie bar. Again, care is needed due to the mess of screws involved here, while most are 14mm, there is a 18mm called for. 

That is the half frame along with all the cross bits attached I left the gearbox out as the motor is not fitting yet. The whole gearbox needs to come out for gearing change as the cover is blocked by other parts of the chassis. 

[alvinlwh 5895]

Step 5 - Frame rail assembly 

This is when the 2 halves comes together to form the chassis. 

I checked that I can actually still fit the gearbox before tightening the screws. I can. 

[alvinlwh 5895]

Step 6 - Sway bar assembly 

Bag 13 also join the party for this. 

Installed on to the chassis. 

And that is this part of the build done. 

[alvinlwh 5895]

Bags 8, 9

Part 4 - Front Axle

This is another multi day part to build. 

Nice to see metal drive and bearings included as standard. Also I spy in the bag, what looks like a diff locker included although there are no instructions on how to use it. 

[alvinlwh 5895]

Step 1 - Bevel gear assembly 

Straight forward build to start off this part. I used threadlock on the screw as it is metal to metal. 

Step 2 - Bevel gear assembly (again?) 

This is just building the diff. I think they made a mistake with the name. 

The diff is not sealed, so no oil in diff, I just greased it up with the standard MST black grease. It felt really smooth. All gears are in metal although the diff cover is plastic. The star shaft is in metal although a similar plastic piece is also included. 

Step 3 - Attaching bevel gear

This step involve putting the gear and diff into the axle. 

All bearings and greased up with the same black grease. 

Step 4 - Axle assembly 

This is just sealing the axle halves, I forgot pictures but it will be seen on the next step. 

Step 5 - C HUB carrier assembly 

This step is putting the steering hubs onto the axle, with the added effect of holding the ends of the axle assembly firmly together. 

 

[alvinlwh 5895]

Step 6 - Wheel axle assembly 

Great care is needed putting the shafts together. The cross pin required is a 10.8 one and it is in the same bag as a 9.8 one (used as a drive pin). I put one together correctly and cannot do the other one correctly until I noticed the different length. 

Step 7 - Attaching CVD axle

Just slide the shafts in until it engages with the diff correctly.

Step 8 - Knuckle assembly R

Step 9 - Knuckle assembly L

Instructions are not too clear on what goes where. Careful examination will show that where the smaller holes are for the threads of the step screws to engage. 

Step 10 - Servo plate & Link mount assembly 

A metal servo plate and link mount is available however they cost £16 and £10 each so I am going with stock plastic first. 

[alvinlwh 5895]

Step 11 - Servo mount assembly 

Again, metal parts are available, for a price. 

Step 12 - Steering servo assembly 

I can just see that adjusting trim on this servo link going to be difficult. 

A 9.2kg Etronix servo will be used, the 15kg JX servo I have tested to draw over 3A. The servo plate must be in the position (note the positions of the "ribs) or it will not fit properly. I had already done one of these on my TCR-M. 

Spring that will "save" the servo. 

Servo saver fitted. 

Step 13 - Attaching steering link

All are held together with screw through balls rather than pop on balls. I suppose that is needed given the rough jumps this truck is designed for. 

That is the front axle assembled. Adjusting toe or steering trim on this will be a pain as the whole thing needs to be unscrewed to adjust. Metal bits again available as an upgrade. Or I may try some Aliexpress all metal turnbuckles in the future. 

[alvinlwh 5895]

Bag 10, 11

Part 5 - Rear axle

This is mostly the same as the front except for the lack of steering mechanism. 

Given that the front and rear mounting are the same, I believe this can be converted to 4WS by using the front axle Bags 8 & 9. Unfortunately MST do not sell bags but individual parts which makes shopping rather difficult. 

[alvinlwh 5895]

Step 1 - Bevel gear assembly 

This is exactly the same as the front so just the completed article. I went with open diff using the stock black grease on recommendation of @smirk-racing.

Step 2 - Attaching Bevel gear 

Step 3 - Axle cover assembly 

Again, just the same as the front so the finished article. 

Step 4 - Axle lockout assembly 

Since no steering, just 2 solid drive shafts for the rear wheels. 

[alvinlwh 5895]

Step 5 - Axle lockout assembly (again?) 

What is interesting here is that the bearings are captive, meaning body clips are not needed on the axle to keep them in before the wheels go on. Disadvantage is that they are more difficult to replace. 

Step 6 - Link mount assembly 

Some M3 x 3 grab screws are used to seal up the servo mounting holes to complete the rear axle. 

The finished rear axle along with the included diff locker and a plastic star shart (MST's spelling), not sure why as a metal one is also supplied. 

Now looking at the finished item, to convert to 4WS, all that will be needed are the steering hubs, CVDs and servo mountings. 

[alvinlwh 5895]

Bag 12

Part 6 - Driveshaft

This seems simple, just one bag is needed but... 

[alvinlwh 5895]

Step 1 - Attaching driveshaft 

As the motor gearbox is off the chassis at the moment, they are attached separately. I may regret this later on once the motor is in. 

Step 2 - Attaching front axle

Careful examination of the instructions is required as there are a lot of arrows showing what goes where. The links and rollbars are making it feel like a spider. 

Step 3 - Attaching rear axle

Fitting in exactly the same way as the front. 

I think there is a mistake in the instructions, parts list called for a long and short drive shaft but the steps called for short front and back. I will figure that out when I finally got the gearbox in.