Amateur Build. HAYA Centurion KIT

[zooma]

The next stage of construction that I decided to attempt was to assemble the suspension system.

A small packet of black coloured STS (2.1 x 7) are used to fix the small "operating arms" and linkage together, and to the front and rear suspension assemblies. The central suspension assembly does not have these "operating arms" or linkage.

During the assembly so far I have only used the one cross head screwdriver. One of these screwdrivers used to be included with every Wedico model truck kit. I have had mine for many years and it fitted the heads of all sizes of screws used to date, and also fitted the small black coloured STS that were used to secure the small "operating arms" and linkage.

I prefer to use a hand screw driver when screwing into plastic so that I can "feel" when a screw is tight and stop before over-tightening any screw and risking damage to the screw heads - or even shearing-off a screw shaft.

In theory, a good torque adjuster setting on an electric screwdriver or small drill can do this perfectly well, but in real life practice - nothing works as well as the Mark 1 hand "feel" or is able to adjust to an infinite variety of variations that can (and do) occur between two outwardly similar looking plastic mouldings.

I was prepared to dip every screw shaft into a pot of Vaseline (petroleum jelly) to help it cut its thread into the plastic components, but so far, this has not been necessary as the plastic used seems to be "self-lubricating" and is very easy (but still firm) to screw into.

The cast metal suspension arms "fit" onto the plastic axles varied when I check-fitted them originaly (before spraying) varying between being fairly tight - and having to be levered back off of the shafts ! The moulded shafts showed various levels of "tracking" marks suggesting that the inside of the mounting hole was not as smooth as it could be - and after I had painted these plastic shafts - they could be even tighter!

I checked the fit of the bore with a 5mm drill and noticed that it was a loose fit in the axle mounting hole, so I run it in every hole just to de-bur any rough "peaks" without actually enlarging the hole size in any way. Then I used a counter-sink de-burring tool on the end of each hole so I was certain that both ends were also smooth and burr free.

The fit of these alloy suspension arms was really nice and free when I fitted them during the final assembly and needed no pressure to slide them onto the moulded axle shafts. The operating arms were fitted onto the moulded shaft that was designed to accept them, the coil springs were slipped onto the mounting lugs on the cast alloy suspension arms, and everything was held in place when the front covers were secured with the most commonly used 2.6 x 6 STS.

The whole suspension assembly build was quick and easy and took a lot less time to complete than I thought it would.

The top picture shows one of the end suspension assembles before the cover is screwed on to secure it. The central suspension assembly does not have any "operating arms".

On my RTR Centurion these "operating arms" were left in the "Kermit Green" colour, but my kit built model will have them sprayed in Olive Drab along with any other un-painted parts that can be seen.

[ongbenghui]

Before you proceed with the assembly, I found that mine has a slight rubbing of front suspension arm to the suspension part.
This caused a "stuck" situation when running over tall obstacles. See

4b46a022-9269-4d1f-bf81-a26bcd09d806.jpg (51.04 KiB) Viewed 568 times

Shown in this picture,

f31b6135-b293-41f8-b48c-12f33be57a33.jpg (59.28 KiB) Viewed 569 times

Hence, I filed a bit of this section here to clear it. See

bf3d2baa-1a35-414f-8479-ad1705968feb.jpg (37.1 KiB) Viewed 569 times

[zooma]

The wheels will be assembled next, so I will check the clearance after I have fitted the tyres ongbenghui. UPDATE:- no problems with binding or rubbing on my wheels after the tyres were fitted - so no modifications were needed.

The wheels are moulded in two halves and need to be removed from some unusually thick moulding runners that show the flow channels used to fill the moulds during the injection moulding process.

After the inner and outer wheel halves are removed from these heavy sprues it leaves a bit of cleaning-up. I chose to cut off as much of these "tags" as I could with a knife and then file and scrape this "flash" back to shape.

Although the outside edge of the wheels will covered by the tyre, it is still important to make the wheels nice and round and not leave any "lumps" of moulding flash on them as this would in turn leave a "high spot" under the tyre.

The inner and outer halves of the wheels plug into each other with 5 plugs and sockets that in turn give the location for the 5 STS (2.6 x 6) that hold the two halves together.

In theory, these plugs and sockets should be able to push into each other in any random position, but I noticed that by check-fitting the various options there was only ONE position where they fitted really nicely into each other allowing the two halves of the wheels to close together fully without relying on the STS to scrunch them together to get a nice flat fit between them.

Once the best alignment had been achieved for each pair of wheel halves one of the two wheel bearings can be trapped in-between them before screwing them together.

The second wheel bearing is not fitted inside the two wheel halves but is left out at this stage as it will be push-fitted over the axle later when the wheels are fitted onto their axles. I did notice that these bearings will not easily slide onto the axles. These axles are an integral part of the suspension castings and will need cleaning-up to allow the wheel bearings to fit over them. This will need to be done carefully as the castings are quite soft and it will be important not to remove too much material from the axles.

Once I have assembled and cleaned-up all the road wheels I will push on the "hub caps" to prevent any paint reaching the wheel bearings and paint them together before pulling them back off and fitting the wheels onto the axles.

It will be nice to see the chassis standing on its own wheels for the first time - even though they will need to be removed again to complete the remaining chassis parts and then making sure that everything is painted before fitting the rubber tyres to the return rollers and the road wheels.

[zooma]

All of the alloy axles needed "dressing" with a small flat Swiss file to allow the wheel bearings to fit onto them.

One bearing was fitted to each axle and then the road wheels were pushed on and secured with a flanged machine screw (2.5 x 5). The alloy axes are already screw- threaded so everything went together very easily.

The hub caps were taken off of their moulding runners (sprues) and cleaned-up before being push-fitted onto the wheels .

I am not sure yet if I will attempt to spray the wheels in-situ or take them off and spray them individually - but I have a little more time to consider this yet as I dig-out the alloy drive sprockets and alloy front return wheels.

[zooma]

The Alloy Drive Sprockets and Alloy Front Return Wheels both come in two halves and need to be joined together.

I noticed that one pair of the front wheels would not fit "flat" against each other, so I did the usual thing of checking to see if swapping them around made any difference - and it didn't - but it did allow me to identify the casting that was causing the problem - it had a small lump of alloy on a flat surface that needed to be removed.

This was quite awkward as it was in-between the inter-locking studs and recess's, but by scraping away with the end of a small flat diamond file I eventually removed it and both front wheels then sat nice and flat against each other (in any combination of outside and inside halves).

The rear sprocket halves fitted each other perfectly and needed no attention.

The front wheel halves need 3 screws in each to join them together and the rear sprockets need 4 screws in each to join them together.

I found a small packet of black coloured machine screws (2.5 x 5) that had 14 screws in it - exactly the number of screws needed to join these alloy wheel halves together - and they fitted - so by process of deduction (!) - I was able to work out these were the screws that were supplied for joining the two halves of these alloy wheels together .

Both pairs of wheels came with the hub caps already pressed into them. The front wheel hubs were eventually "extracted" by gripping them with a heavy pair of flat jaw engineers pliers and pulling and twisting them apart. This was not easy and took some effort to remove the hub caps that were a "force fit" and were without the regular "O" rings to retain them. I doubt these could "fall of" in use (!) but they will take some effort to press them back in when they are mounted on the adjustable front axle assembly.

The hub caps also came press-fitted into the rear sprockets. Unlike the front hub caps that have nice chunky flat edges to grip onto, these have tapered edges that give nothing to get a good "bite" onto! I am going to get a "drift" that can fit inside the small axle hole and punch them off from the inside, but this cannot be done when they are re-fitted onto the tank!

Being able to remove the rear hub caps from the sprockets (without damaging them) is already causing me some concern! I need to remove these hub caps from my RTR HAYA Centurion as I need to change the motors to make it drive and steer better, but being able to remove the rear sprocket is quite an important necessity to maintain the tanks in any case, so I am hoping that the rear caps on my RTR are not such a tight "force-fit" as these were.

[zooma]

Having prepared to drift-out the alloy front wheel hub cap - it more or less fell out as I touched it with the parallel drift pin!

A complete contrast to the rear alloy drive sprockets that felt like they had been welded-in (by comparison!)

This is probably just as well as the shape of the front hub caps leave very little to "get a grip on" when they need to be removed - they may even benefit from having a little Blue Tack put on them to help stop them falling-off!

[zooma]

As the rear sprockets and front return wheels are both made from cast alloy (and they will be working quite hard) I have decided to use an acid etching primer to give them a good solid base for the paint to bond onto.

I have previously used this on alloy parts when I used to make Wedico r/c trucks that are all metal, and it provided a good long lasting base coat.

This is a fairly fast drying primer, but I will leave it for a few days and paint these wheels and sprockets along with some other parts that need some colour cover on the chassis tub.

[zooma]

Despite the can of Acid-8 being just as old as my Tamiya rattle cans it has sprayed and covered the metal sprockets and return wheels nicely.

When I return home mid -week I will get some Olive Drab paint on these and continue with the chassis tub build.

[Ecam]

I have never heard of the Acid-8 primer (not sure we have it in the States). I use an etching primer and it has a green color (perfect for my OD paint jobs). Love the work you are doing with this thread, and with a lack of detailed instructions, I am sure it will be helpful to many.

I once did a belt driven supercharger on a Jeep Wrangler - and later I was contacted by the manufacturer to create an installation guide (I learned later I installed the second unit he built, the prototype was on his personal Jeep). The Jeep I built on was in a few off road magazines and later went to the SEMA show in Las Vegas. For a couple years I was the "Tech" department for the supercharger manufacturer.

[ColemanCollector]

This is turning out to be more of a kit than I thought it would be. And that's a good thing! An interesting build you're documenting that will be quite useful.

Mike.