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tacaruth

Well Known Member
Hi All,

Does anyone have any good tricks for installing the cotter pin that goes through the axle nut on a main gear wheel? Every year I check my wheel bearings and brake pads during my annual condition inspection. When this task is complete, the problem is getting the cotter pin back through both sets of holes on either side of the axle. The holes are drilled to the size specified in the plans but I was thinking of drilling them out a little. Any other ideas?

Tom
RV-7A N175TJ Flying
 
Are you trying to re-install the same cotter pin? I have always treated cotter pins as items you use once and then throw away.

If you are having another type of problem then it's not clear from your description.
 
The cotter pin is usually easy to get in the first side. While trying to stab the other side try rocking the nut back and forth.
And as has been already mentioned, ALWAYS use a new cotter pin.
 
I use a file and taper the end(s) to a more pointed shape. Seems to help in getting the pin started in the second (blind) hole.
 
Thanks

Thanks for the ideas. Yes, I use a new cotter pin each time. I have not tried sharpening the end to a point. Thats a good idea.

Tom
RV-7A N175TJ Flying
 
Sometimes it goes in easy other times it's a struggle. Seems that you have to bend the cotter pin just a tad sometimes to clear the rim or tire.

I've always reused them before, but the consensis seems to be not to. Looks like I'll be stocking up on cotter pins.
 
There are several things you can try:

1. With the wheel off the axle, feel inside the axle area and be sure there is no metal bur around the cotter pin holes you drilled.

2. Taper the pin as suggested. If the pin is long enough, make both legs the same length, and then give it a good taper. You will be cutting off both legs eventually to get it to fit around the axle nut.

3. You can modify the axle nut end surface to accept the axle lift bar (Avery ??) This change will allow you to look inside the axle as you attempt to position the cotter pin.

4. Take a new cotter pin to the hobby store and find the brass tubing section. You will want to get a short length of tubing...and small enough to slide through the axle nut holes, but large enough that the longer leg of the cotter pin will just fit inside the tubing (or taper it). At the airplane, with the wheel and axle nut in position, insert the brass tube through both holes. Now, use the cotter pin to gently push out the brass tube. The cotter pin is using the tube to "chase" and this should guide the pin to the opposite hole.
 
Thousands installed easily.

tacaruth said:
Hi All,

Does anyone have any good tricks for installing the cotter pin that goes through the axle nut on a main gear wheel? Every year I check my wheel bearings and brake pads during my annual condition inspection. When this task is complete, the problem is getting the cotter pin back through both sets of holes on either side of the axle. The holes are drilled to the size specified in the plans but I was thinking of drilling them out a little. Any other ideas?

Tom
RV-7A N175TJ Flying
Click to expand...

I have installed thousands very easily.

The nut wiggle is a big help.

I would try putting the cotter pin with just the nut wiggle, if that did not work immediately, I would pul the cotter pin out and bend the long ended single prong so the point ended up in the center line of the pin and put it back in the hole.

From my experience changing GA tires, 99.99 percent success.:cool:

If that does not work, the holes are too small or out of alignment.:mad:

Best wishes.
 
RScott said:
I use an awl in the opposite side to insure the holes are aligned.
Click to expand...

This reminds me of a trick I use to do on used cottern pins.:rolleyes:

Anywho, if the ends are not togeather, no matter how much you wiggle the nut the pin is not going in the hole. The legs need to be tight togeather. Take the awl and use it to spread the pins "legs". (maybe a smaller diameter "thing" would be better) Take a pair of pliers and gently squeeze the legs togeather. This will give them alittle angle to bring them togeather when you remove the awl. Alittle practice and you'll get what I mean.

I hope that makes sense.
 
On the tough ones, I file my tip and put the flat of a large blade screwdriver over the top and tap with a small mallet or wrench.
 
The same applies to cotter pins as it does to get to Carnige Hall...

Practice, practice, practice....;)

Having installed thousands of these little devils, the longer the distance between the two holes...the harder it is. I installed two last weekend in the same application for a mechanically challenged friend...All it takes its to be able to visualize the path to the second hole...and the experience of installing thousands of them prior:D
 
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