Pinion Sliding Loose

[ERevoBL96]

My e Revo Mamba Monster will not keep a Pinion on the shaft. It hasn't done this ever until about 2 weeks ago. Stripped out my spur gear, got another, stripped, got another, stripped. I red loctited the set screw threads and screwed it in the gear. I ran on a 3/4 stripped spur gear today, and it still slipped on the shaft. I don't know what to do. What's causing it to be pushed forward and stripping my spurs?

[87 GN]

I dremel a little off the flat of the motor shaft, roughs it a little. Lets the set screw get a bit on the shaft.
Get the set screw tight & let the loctite set up for 24 hrs..

[ERevoBL96]

Is there any other solution? I don't feel comfortable dremeling on the motor shaft, and I don't have a dremel.

[bazookamaxx]

dremel or file a thin cross on the bottom of the grub screw, some grubs you can get are concaved and seat well, these are usually flat or even a bit pointy. Then do the loctite

[BEN_]

You mentioned that you used red locktite.

Try this.

Put a few drops on the shaft and in the pinion. Then put the pinion on the motor's shaft.
Take the set screw out. Squeeze the locktite into the pinion's hole and give the pinion a couple spins. This will coat the motor shaft and ensure that locktite is getting on the threads. It will also spread the locktite on the shaft.

Then put a drop on the set screw and thread it in, ensuring that the screw is pressing on the flat portion of the shaft, crank it down.

Clean up and let dry.

[87 GN]

Ben it will never come off. You will need some heat to take the pinion off at a later date, but that should do it...

^I watched a youtube vid & that is what he did on his XL & 750 kv....

[candy76man]

You mentioned that you used red locktite.

Try this.

Put a few drops on the shaft and in the pinion. Then put the pinion on the motor's shaft.
Take the set screw out. Squeeze the locktite into the pinion's hole and give the pinion a couple spins. This will coat the motor shaft and ensure that locktite is getting on the threads. It will also spread the locktite on the shaft.

Then put a drop on the set screw and thread it in, ensuring that the screw is pressing on the flat portion of the shaft, crank it down.

Clean up and let dry.

I wouldn't do that....He's going to end up having to cut the pinion off when it's time to change it...that set screw strips easily enough with just blue loctite in it. Blue loctite will hold just fine and will usually allow you to remove it later on without breaking out the dremel and buying a new pinion.

Clean the motor shaft, entire pinion, and set screw with alcohol (or even better acetone) to remove any oil residue, then put the pinion on the shaft, put one drop of blue loctite in the set screw hole, then put the set screw in and tighten it down. let it sit at least 12 hours and I guarantee that pinion isn't going to go any where....but it will still be removable without using a torch and destroying the temper on your rotor.

[Brewers74]

Tack weld it on...lol
Just kidding

[BEN_]

Ben it will never come off. You will need some heat to take the pinion off at a later date, but that should do it...

^I watched a youtube vid & that is what he did on his XL & 750 kv....

Hahaha Yeah he does do that. I actually first learned this in the military. I used to be a NAVY helicopter mech and we never assembled anything without applying adhesive first. It made assemblies rock solid and a nightmare to take apart. Good ole MIL-S-8802.


He also mentions what it takes to remove it too.

Ok here is how to get the pinion off.

Set your soldering iron to its hottest temp. And hold the iron on the set screw for a few secs. That will soften the locktite.

Make sure you use a quality driver too. It will help prevent stripping.

[ducati777]

Sooooo in normal operation the pinion shouldn't experience any side loading.

Because this is an ongoing problem, it implies the pinion isn't squarely lined up with the spur gear.

Are you confident that:
Motor bearings are good
Input shaft to the transmission isn't bent
motor mount plate is flat
the bolt that goes through the plate to the mount is secure
the bottom hinge for the motor mount is in good shape
the slipper pads are wearing evenly
the bearing in the spur is good

Hmmmm what else....

[BEN_]

Sooooo in normal operation the pinion shouldn't experience any side loading.

That's true and might be the case. I have had pinions that have a sloppy fit on the motor shaft and they would work loose every pack. They wouldn't even mesh smoothly.