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Thread: My HG P407 Story

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Old 03-05-2019, 02:24 PM   #1
Join Date: Feb 2019
Location: Uk Guildford Surrey
Posts: 5
Default My HG P407 Story

Firstly its probably best to start at the beginning about 35 years ago , I was 14 then and deeply into off road racing but one Tamiya model did catch my eye , the Toyota 4x4 Pick Up or Hi Lux as its commonly known , i was always in awe of its scale detail but we laughed at its rigid suspension and poor off road ability ,those things and the price put me off . Now the years spool by to the present day and after nearly a 30 year brake I'm back into RC cars , mostly restoring vintage off road racers but I've increasingly been drawn to watching youtube clips of scale crawling and i started to wonder if I'd enjoy a change of pace .
This is when the HG P407 came to my attention and the boxes started to get ticks in them .
A good scale look.
Leaf spring suspension .
Three speed gearbox .
Lots of upgrades intended for the Bruiser already on the market .
So in January one arrived on my doorstep and the journey began and my plan from the off was to create the best crawler i could from it on a fairly tight budget .
My initial thoughts were WOW! you get a lot for the money , then we move into what it's faults are .
1 The shocks leek badly
2 The suspension is over sprung
3 The tires are too hard
4 The steering has too much slop
5 The suspension has little articulation .

The shocks
Right at the beginning i was in two minds as to weather to replace or rework the leaking shocks , the first thing i did was fill them with 15WT oil , the damping effect was so strong that instead of the piston passing through the oil it instead just popped out the floating constant volume cap ! so i began by filing two flat sections on the side of the piston heads , i carried on until i got the damping effect i wanted .
Next was to address the leaks , they leaked at both ends ! so i started at the floating cap end first , what they had done was cut too deep a groove for the O ring meaning there was no seal at all ! out with the plumbers tape , removing the O ring first i wound some plumbers tape into the bottom of the groove , a little trial an error and i had a good seal once the O ring was fitted . The shaft seal came next , inside the screw on cap there was a washer a plastic spacer and an O ring , the washer was meant to slightly compress the O ring but the washer was to wide a diameter to fit into the recess for the O ring so it gave no compression at all , a quick rummage in my spares and i found some spring washers that would fit perfectly and also offer a little more compression to the O ring , it worked ! so i now have working shocks .
Now I'll add this here but i actually did this a lot later , the shocks have two additional problems , the first is the coil spring that goes over the shock shaft , why ? the leaf springs are so stiff already ? but that's only half of it , when the suspension is compressed the coil spring closes up and limits travel ! so ditch that coil spring ! Lastly at the bottom of the shock it attaches to the axle with a stepped metal sleeve and a screw but that sleeve does not allow much articulation at all , out with the Dremmel , what i did was open out both sides of the hole in the shock cap to make a conical hole only leaving the center of the hole uncut , this allows the stepped sleeve to pivot in the hole .
The bottom one has been opened up.

The left one shows the increased articulation , in fact more than shown .

The Springs
The springs are very stiff , I've already suggested you ditch the coil springs from the shocks but that has little effect so we also need to remove a leaf from the pack , at the front i remover the shortest leaf and at the rear the middle length leaf , while at it I also did the Chino mod , this is where you use a grinder to taper the ends of the leaf at the eye bush so it can pivot in the shackle . This i found gave me the best articulation and suppleness all round .
Again I did this later on but I'll throw it in here as it makes it tidier , the U bolts that secure the leaf springs to the axle have the threaded end and nut's at the bottom , this reduces clearance and offers another place to snag on so I made up a new set from M3 studding , heating the studding and bending it around a 10mm shaft , when fitted they are facing upward not down as shown .

I did this at both ends , it does mean you loose the front diff skid plate but i never liked it any way as it just looked out of scale .

The tires are just too hard and not a nice scale tread pattern in my view , i saw on another forum that someone had fitted Austar AX -3021 tires , very cheap so i ordered some and so far I'm really happy with them , much softer and a nice scale looking tread pattern .

The steering slop is a heritage thing , just like its sire the Bruiser its an awful setup so a front high torque servo mod was in order .
I did my own take on the front servo mod , moved the front shocks behind the axle at the bottom and top , for the top mount I used the front screw hole for the gearbox mount cross member and there is a hole for the old steering pivot assembly that just needed elongating a little to line up , strangely the hole for the steering pivot is on the other chassis rail as well ? So that just needed elongating a little as well the bottom already has a mount for the shock behind the axle .
Then I moved the L section steering arm from the left facing back to the front on the right knuckle .
The front cross member already has two threaded holes in the top of it so I used them to mount an L section piece of aluminium on top and over the back for mounting the servo , this mod only requires two holes in the chassis rails to be elongated to fit the top shock mounts otherwise its already there , all you have to make is the servo mount and a track rod , the rest is just nuts and bolts .
I'll post pictures tomorrow .

I got even luckier with the servo lead , I thought I'd have to extend it but because of the Y harness for the lighting system I had just enough length

Last thing mechanical that i though needed changing was the motor , so i fitted an Absimma 55T motor and I'm very happy with it .

So that's all the technical stuff so lastly the cosmetic stuff , the body was treated to a distressed look by adding rusty sections using the salting method , the interior got painted , i made some internal door panels and installed Shaggy and Scooby as driver and co driver.The body also got a full lighting kit with working indicators , brake and reverse lights .

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