drive shafts

[twisted]

ive been using stampede shafts with metal yokes with no problems.

[fatwoul]

I received my HR shafts yesterday, and so far they have proved very good.

[fatwoul]

I spoke too soon about the HR driveshafts. I discovered today that they have a really major design flaw.

The pins in the universal joints work out, and after 10 minutes one of mine had fallen out completely! Fortunately, I was watching for it, and as soon as I noticed the front wheels lose power, I stopped and looked for the pin, and it was directly beneath the vehicle.

I'm guessing that this doesn't normally present a problem when these sort of shafts are used on forwards only vehicles, because the constant forwards drive direction holds them in place. But on a crawler going back and forth and juddering over rocks, they can work out much more easily. Or have I just got a pair of bad ones?

The driveshafts themselves are great, and I really want to keep using them because they are the best functioning so far. But this is a really serious problem that stops me being about to use them, until I can work out a solution.

So, ideas guys? I'm really stumped the best way to contain the pins.

[Joat]

Originally Posted by fatwoul

I spoke too soon about the HR driveshafts. I discovered today that they have a really major design flaw.

The pins in the universal joints work out, and after 10 minutes one of mine had fallen out completely! Fortunately, I was watching for it, and as soon as I noticed the front wheels lose power, I stopped and looked for the pin, and it was directly beneath the vehicle.

I'm guessing that this doesn't normally present a problem when these sort of shafts are used on forwards only vehicles, because the constant forwards drive direction holds them in place. But on a crawler going back and forth and juddering over rocks, they can work out much more easily. Or have I just got a pair of bad ones?

The driveshafts themselves are great, and I really want to keep using them because they are the best functioning so far. But this is a really serious problem that stops me being about to use them, until I can work out a solution.

So, ideas guys? I'm really stumped the best way to contain the pins.

Put a sleeve over it , that's how the topcad ones are, though there is a setscrew the sleeve makes it that much less likey the pin will come out,also protects the drive shaft so the pin is not exposed and will not get caught up on rocks and such.

[fatwoul]

Originally Posted by Joat

Put a sleeve over it , that's how the topcad ones are, though there is a setscrew the sleeve makes it that much less likey the pin will come out,also protects the drive shaft so the pin is not exposed and will not get caught up on rocks and such.

Thanks Joat. Since posting, I've looked more carefully and discovered that the pin should be held in place with a tiny hex worm screw, but for some reason, none of mine are tightened, or they have loosened. It may be sufficient for me to tighten them, but they seem to need an allen key somewhere between 1.27mm (too large) and 0.9mm (too small). Once I can find the right allen, I might be able to tighten it, and throw some threadlock in while i'm at it.

I might also file a small flat section on the pin for the screw to settle onto, so make it less likely that it will work free.

I'm also considering a sleeve of some sort, as you suggested. The problem is that because its on the universal joint itself, sleeving it will limit its movement. I will have to use plastic or something to make something.

Just seems so weird that they weren't tight already. I also kinda think that they could perhaps supply the allen key, since the screws are so small.

[twisted]

Originally Posted by fatwoul

Thanks Joat. Since posting, I've looked more carefully and discovered that the pin should be held in place with a tiny hex worm screw, but for some reason, none of mine are tightened, or they have loosened. It may be sufficient for me to tighten them, but they seem to need an allen key somewhere between 1.27mm (too large) and 0.9mm (too small). Once I can find the right allen, I might be able to tighten it, and throw some threadlock in while i'm at it.

I might also file a small flat section on the pin for the screw to settle onto, so make it less likely that it will work free.

I'm also considering a sleeve of some sort, as you suggested. The problem is that because its on the universal joint itself, sleeving it will limit its movement. I will have to use plastic or something to make something.

Just seems so weird that they weren't tight already. I also kinda think that they could perhaps supply the allen key, since the screws are so small.

use heat shrink tubing for the sleeves.its flexible but will need to be replaced every so often.

[Joat]

Originally Posted by fatwoul

Thanks Joat. Since posting, I've looked more carefully and discovered that the pin should be held in place with a tiny hex worm screw, but for some reason, none of mine are tightened, or they have loosened. It may be sufficient for me to tighten them, but they seem to need an allen key somewhere between 1.27mm (too large) and 0.9mm (too small). Once I can find the right allen, I might be able to tighten it, and throw some threadlock in while i'm at it.

I might also file a small flat section on the pin for the screw to settle onto, so make it less likely that it will work free.

I'm also considering a sleeve of some sort, as you suggested. The problem is that because its on the universal joint itself, sleeving it will limit its movement. I will have to use plastic or something to make something.

Just seems so weird that they weren't tight already. I also kinda think that they could perhaps supply the allen key, since the screws are so small.

Oh the pin in the cv came loose, I though you where talking about the slider pin, yes make a flat spot, I do that to all my cv pins, but I would think of sleeving the slider pin.
As for the size , you sure it's not a 1.5mm , 1.27 is pretty small and rare, 1.5 seem to be the most common, I have the topcads and they use 1.5mm sets.

[fatwoul]

Originally Posted by Joat

Oh the pin in the cv came loose, I though you where talking about the slider pin, yes make a flat spot, I do that to all my cv pins, but I would think of sleeving the slider pin.
As for the size , you sure it's not a 1.5mm , 1.27 is pretty small and rare, 1.5 seem to be the most common, I have the topcads and they use 1.5mm sets.

Nope definitely not 1.5. The ends of each shaft assembly still use the stock pins to hold the shafts onto the transmission and axles, and those pins are 1.5. But the pins in the ball joints need a much smaller key. I have 1.5, 1.3, 0.9 and 0.7. 1.3 is too big. 0.9 is too small, but you can feel it catching as you turn it. So I reckon a key of 1mm would probably do it. Problem is that no sets ever have a 1mm. Even HR's own set of 6 hex keys doesn't include a 1mm.

Oh, and having removed the shafts, I've now discovered that the loose pin carved a big juicy gash in the side of my Goat motor! Fortunately its in the metal band that I can replace, but still, this is a really nutty design flaw with these shafts, and very disappointing considering how well the rest of the shaft seems to be put together, and how well they could perform if only they solved the pin problem