Hi
The nitro buggy thing is new to me so forgive me if all of this is obvious!
Having just built my HotBodies D8 buggy I saw on some of the forums that there were some problems with the CVD drive shafts failing.
My research showed that this was for two reasons:
Problem 1: The Pipe Cutter Effect. Already fixed by HotBodies
Firstly, on the front it appeared that the front steering lock was more than the outer end of the shaft would allow for, resulting in a "ring" being scored at the wheel end of the shaft just as it widens to form the ball. This caused the shaft to be weakened at this point and snap straight through. Its a bit like a pipe cutter grinding a ring around the shaft.
My D8 supplied in Dec 08 was already supplied with updated shafts that were prebuilt in the kit. I can see that these have a chamfer ground around the edge of the ball socket allowing for more front turn angle (or suspension travel). The "pipe cutter ring thing" would appear to be impossible with these shafts.
Problem 2: Drive Pins Comming Loose
The second issue appears to be with the CVD drive pin comming loose and popping out (or half out) of the joint causing it to wreck itself. Again, my drive shafts were prebuilt in the kit and I tried to remove the pin lock grub screw... its well threadlocked in there!
As a secondary measure I obtained a set of GMK Supply "CVD Condoms".
These fit over the shaft prventing the pin from comming out even if the grub screw comes loose. You get six in the kit, two are slightly longer for the internal front and rear shafts whilst the 4 shorter ones look after the outer drive axle CVDs.
This is fine as far as it goes but I was not happy with the fit around the front hub carrier. The CVD condom seems too large and binds on the front (the rear is fine). As seen below there is little to no clearence around this area once the condom is in place:
Plan B: The DIY Heat Shrink Mod
Plan B was to use 1/2 inch heat shrink tubing. First cut approx 12mm of tubing and place in over the conical part of the outer drive shaft leaving and equal overlap each end.
Next apply heat to shrink the wrap down (ok I used the kitchen gas hob.. please use a method you are happy with and don't burn yourself!). Finally trim the excess tube off so to ensure that its the steel part of the axle that snugs up against the bearing in the carrier when the shaft is located in the hub.
The final result is smaller and neater than the GMK product (in my opinion). It also fits in the front end without binding. Below you see my heatshrinking job on the left and the GMK condom on the right.
Notice the increased clearence around the front hub carrier below.
Hopefully this will help people preserve the lives of their drive shafts.
Regards
Mark
