broke again

[Lt.Doomsday]

i'm running the maxium ST outside today in my driveway.up the driveway,down and doing circles{not donuts}.i turned it to head back up the driveway and it just stops dead.the motor is still running,but it isn't moving.i get up and look at the back of the truck were the tranmission is and the right side shaft that goes into it came out.

i was thinking of popping it back it,but i want a perm.fix to this,anyone got a way on how to fix it?

 

[SkyMaxx]

If this is a dog bone and diff cup style axle, then the only permanent fix is to upgrade to CVDs. If it is something else, there might not be a really permanent solution. Depending on what is going on (WOT, donuts, etc.) throwing a dog bone is not uncommon. Just loosen things up enough to reseat the axle and move on.

 

[Lt.Doomsday]

it's a dogbone

 

[SkyMaxx]

You may want to look into a set of CVDs to replace the dogbones. They are a little harder to unseat, but the potential still exists to pop one.

 

[Lt.Doomsday]

something like this,right?
http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXCNR0&P=ML

 

[mcvickj]

Correct.

 

[Lt.Doomsday]

the thing is the cup that sets them into the tranmission came out also

 

[SkyMaxx]

Sounds like you lost a set screw. Usually cheap and easy to replace.

 

[Lt.Doomsday]

it's still in the cup

 

[SkyMaxx]

Then perhaps it just needs to be tightened.

Do you have a digital camera, as a picture of your problem would be very helpful.

 

[Lt.Doomsday]

sorry for such a blurry and big pic,but as you can see that isn't right
{Pic Removed}

 

[SkyMaxx]

Try to take the zoom out a notch or two and move back from the rear of the truck. You are inside the focal length of the camera.

From what I can see, the diff cup is just come loose from the pilot shaft of the diff. I'd say remove the turnbuckle to allow the a-arm to fall away from the diff. This will pull the dog bone out of the cup, and allow you better access to the cup.

Once you have access to the cup, reseat it and tighten down on the set screw. You may want to use some loctite on that set screw.

If the set screw is a pinned set screw (as in a pin that is supposed to pass through a hole in the pilot shaft) you may need a new one. As what you show in the picture could indicate that the pin is sheared off.

I'm betting the set screw just loosened up.

 

[Lt.Doomsday]

sorry about the pic,i usually don't take close pictures.

i just got back from downstairs and got the cup off,the set screw is tight and won't budge but it comes off easily from the pilot shaft.the set screw doesn't go though the the other side.

 

[SkyMaxx]

Sounds like the set screw might be messed up. Did you use loctite on it at some point?

Regardless, boil a pot of water. Drop the cup in the water and let it soak for about two minutes (long enough to heat up the metal really well). Pull the part out of the water, carefully so you don't burn yourself....tongs of some sort are really good for this. Let the part cool til you can handle it, but not all the way to room temp.

Now, try and remove the set screw. The heating should expand the metal and break down any loctite used and make the set screw a little easier to remove. If it still won't budge, you may need to try another brute force method...or you may need to purchase a new cup.

BTW, you can remove the picture from your post, now. Thanks.

 

[Lt.Doomsday]

nope,i never used any loctite on it.i only used locite on the screws that hold the motor cause of the vib. shook them loose.you know looking at the inside of the cup,i swear it look like the set screw was welded to the cup to prevent any type of over-tightening.

 

[SkyMaxx]

Then you may need to purchase a new one.

The weld look might be caused from the running of the RC. Over time it might have just worked itself into a bind and flattened out the end of the set screw.

You can try the boiling method I mentioned above. It might break it up, but there is no guarantee.

Note, loctite should be used on any metal to metal contact. That includes things like set screws. It helps prevent them from backing out and allowing this kind of thing to happen.

 

[Lt.Doomsday]

i'l try the boiling tomorrow,i'll take it apart again and try it.if it don't work i'll get two cups for the rear tomorrow or friday from the LHS.

 

[Lt.Doomsday]

just got done with boiling it for the hell of it and it's welded shut.the good thing is the left one was tight and with the smallest allen key i have,unscrewed it.thx for your help.i should have used locite,but i thought it came with locite on it already.guess i was wrong.

 

[SkyMaxx]

Glad to have helped.