Tire change tips (Matco)?

[Chris S.]

Note: I posted something before asking for help and deleted, sorry if that was confusing.  
 

I think I should be able to do a tire change myself yet I’m getting stuck on removing the cotter pin and the nut(?) that it is inserted through. I think if I get the pin out the nut won’t be a big deal so anyone got tips for the pin or some advice on this in general? My attempts to get the pin out with some pliers have made it a bit ugly but I don’t think it is damaged. I feel like there had to be an easier way to do this. 
 

Thanks in advance,

 Chris

[Warmi]

What I generally do is to straighten the flared out end so it lines up with the other end and then cut it as close to the nut as I can on the flared out side and only then pull it out.

[Roger Lee]

Straight up the bottom bent over ends. Then grab the top looped part with a pair of pliers and then just rotate the pliers either right or left. The pliers rotates on the nut and gives really good torque advantage. The pin comes right out.

[Chris S.]

Both really helpful, thank you. 

Another dumb question then: Warmi's reply seems to imply that you replace the pin as well. If that's true is this some special aviation grade pin I need from Flight Design or can I just get another from the hardware store? 

Also does anyone happen to know what size the nut is?

Thanks again for all the help!

[Warmi]

Cotter pins are one time use items.

I get mine from here https://www.aircraftspruce.com/menus/ha/cotterpins.html but someone else here on this forum can perhaps help you with exact size you will need - I don’t have Matco wheels.

[Chris S.]

5 hours ago, Warmi said:

Cotter pins are one time use items.

I get mine from here https://www.aircraftspruce.com/menus/ha/cotterpins.html but someone else here on this forum can perhaps help you with exact size you will need - I don’t have Matco wheels.

Really appreciate the link, thank you. 
 

Anyone know the right size for the Matco?

[Roger Lee]

You can get cotter pins from any hardware store. Don't but a cheap aluminum pin. Just buy a pin that fits the hole size. Buy an assortment and you'll have others when you need one. The pin just keeps the axle nut from unscrewing. The nut is NOT tightened all the way down on tapered roller bearings. The nut tension just keeps the bearing from turning with the wheel.

[Jim Meade]

I went to the MATCO web site and found all the information in less than 5 minutes.

[Chris S.]

49 minutes ago, Jim Meade said:

I went to the MATCO web site and found all the information in less than 5 minutes.

Hi Jim,

Great, care to share? I don't see anything in the maintenance manual about the part number. Some of us are still pretty new to all of this and this forum is a great source of information to get us going. 

To be clear, I too can see cotter pins on the Matco site. I see at least 4 different sizes. 

----

Chris

 

[Skunkworks85]

19 hours ago, Chris S. said:

Note: I posted something before asking for help and deleted, sorry if that was confusing.  
 

I think I should be able to do a tire change myself yet I’m getting stuck on removing the cotter pin and the nut(?) that it is inserted through. I think if I get the pin out the nut won’t be a big deal so anyone got tips for the pin or some advice on this in general? My attempts to get the pin out with some pliers have made it a bit ugly but I don’t think it is damaged. I feel like there had to be an easier way to do this. 
 

Thanks in advance,

 Chris

Chris,

I am not trying to be rude or discourage you from doing your own work, But I feel this needs to be said.

If you are having trouble understanding how to use a cotter pin, I think it is in your best interest to get some training from a mechanic(A&P, LSRM, ECT) before you attempt to do these items yourself. I would suggest you get someone involved to show you best practices before any attempt is made. Maybe have someone monitor your work? or show you how to do one side, then they can watch you do the other side?

 

 

[FlyingMonkey]

And remember when the wheel comes off the bearings are going to try to fall out on the floor.

[Chris S.]

1 hour ago, Skunkworks85 said:

Chris,

I am not trying to be rude or discourage you from doing your own work, But I feel this needs to be said.

If you are having trouble understanding how to use a cotter pin, I think it is in your best interest to get some training from a mechanic(A&P, LSRM, ECT) before you attempt to do these items yourself. I would suggest you get someone involved to show you best practices before any attempt is made. Maybe have someone monitor your work? or show you how to do one side, then they can watch you do the other side?

 

 

I appreciate this and don't take it the wrong way. That was my original plan and one I will likely still stick with but I have no idea if a local shop is going to have the right pin on hand or has ever taken apart a similar wheel so I want to have some idea going in even if I don't do it myself. 

[Tom Baker]

On the Matco wheels I think the hole for the cotter pin must be metric. The standard 1/8" pin is to tight, and the 3/32 pin is to loose. You can ream the hole in the axle slightly and use the same standard cotter pin the other aircraft wheels use.

[GrassStripFlyBoy]

Chris - If you're ordering any parts from Aircraft Spruce or such, you may want to include some stick on wheel weights.  Then go to Harbor Freight and pick up a motorcycle wheel balancer, and when you have the tire / tube back on the wheel do a balance prior to reinstalling on the plane.  Especially if you have the larger Tundra tires, but even the smaller tires need to be balanced.  This will help with some wheel shake when you take off, out of balance leads to some vibrations.  Not end of the world but easy enough. there are a bunch of videos on YouTube to help explain the process, just stick on weights to offset the heavy side of things.

[BravoFoxtrot]

Tom said: "On the Matco wheels I think the hole for the cotter pin must be metric. The standard 1/8" pin is to tight, and the 3/32 pin is to loose. You can ream the hole in the axle slightly and use the same standard cotter pin the other aircraft wheels use."

On Matco's site one of the cotter pins they list is "MSC.11X2COTTERPIn Z/P" My translation of this is: Miscellaneous, .11" x 2" Cotter Pin, Zinc Plated. Assuming(!) I am correct, this would have a diameter of 7/64", putting it in the middle of Tom's tight/loose above.

BTW, I have also looked over the Matco website and cannot find a direct reference to the correct size cotter pin.

[Warmi]

When I started out trying to do minor servicing things like tires , oil etc ... back in 2017 I was asking very same questions and I between googling stuff and talking to people on forums, I was able to figure out pretty much everything. 

I mean basic stuff is NOT that difficult  - I wouldn't touch certain heavier tasks related to engine maintenance because these require specialized knowledge and lots of experience but most of that stuff is pretty trivial - beside the engine, these planes are not that complicated.

[Tom Baker]

1 hour ago, Warmi said:

When I started out trying to do minor servicing things like tires , oil etc ... back in 2017 I was asking very same questions and I between googling stuff and talking to people on forums, I was able to figure out pretty much everything. 

I mean basic stuff is NOT that difficult  - I wouldn't touch certain heavier tasks related to engine maintenance because these require specialized knowledge and lots of experience but most of that stuff is pretty trivial - beside the engine, these planes are not that complicated.

While some of this stuff can be fairly simple it is also pretty easy to mess it up. Last year I worked on a CTLS that the nose tire was not centered, and almost rubbing on the fork. When I dug into it to straighten it out the wheel was assembled completely wrong. How hard is it to put something back together the same way it come apart? On top of that they had installed a tube for the 4.00x4 nose tire on a 6" rim and 4.00x6 tire. This was either done or supervised by the director of maintenance at a university. This was just the tip of the iceberg for this airplane.

[Warmi]

6 minutes ago, Tom Baker said:

While some of this stuff can be fairly simple it is also pretty easy to mess it up. Last year I worked on a CTLS that the nose tire was not centered, and almost rubbing on the fork. When I dug into it to straighten it out the wheel was assembled completely wrong. How hard is it to put something back together the same way it come apart? On top of that they had installed a tube for the 4.00x4 nose tire on a 6" rim and 4.00x6 tire. This was either done or supervised by the director of maintenance at a university. This was just the tip of the iceberg for this airplane.

Are you talking about Lewis University ?  

Anyway when I first time disassemble something that is composed of more than a few parts , I just document  the whole process with a few key pictures - with all these digital cameras included in every smartphone it takes no time to do it ...

[Tom Baker]

5 hours ago, Warmi said:

Are you talking about Lewis University ?  

 Yes!

[Roger Lee]

A cotter pin doesn't need to be an exact perfect match to the hole like a nut on a bolt. If it's a tad snug or a tad lose in the hole the pin only keeps the axle nut from unscrewing itself while the wheel turns. I'm not saying put some tiny thing in there, but it doesn't have to be a perfect match forced in pin. Matco is US standards. I use nothing but US cotter pins and have been since working on CT's since 2006.

[Tom Baker]

3 hours ago, Roger Lee said:

A cotter pin doesn't need to be an exact perfect match to the hole like a nut on a bolt. If it's a tad snug or a tad lose in the hole the pin only keeps the axle nut from unscrewing itself while the wheel turns. I'm not saying put some tiny thing in there, but it doesn't have to be a perfect match forced in pin. Matco is US standards. I use nothing but US cotter pins and have been since working on CT's since 2006.

Roger, I have been working on CT's since 2007, and airplanes since 1983. While a cotter pin does not need to be close tolerance, it shouldn't be loose in the hole. My experience with the Matco wheels has been the cotter pin they provide works fine. The standard 1/8" pin I use on most aircraft will not fit through the hole. A 3/32" cotter pin which is the next size down for aviation pins is too loose in the hole to meet my standards. The original hole in the axle is I would guess is 3mm, it is slightly smaller than 1/8".

[Chris S.]

So after all that the tire change was dirt simple and I used one of the pins ordered from Matco (thanks @BravoFoxtrot and @Tom Baker). The hardest part was getting the plane up on the ladder stand by myself and then getting the old pin out of the hole (thanks @Roger Lee for the tips). 

The first tube failed spectacularly when I put a little bit of air in it. Either I pinched it or it was just a bad tube. The second went fine and I did some flying with it today with no issue. I did order some new tubes from Desser since they seem to be the ones recommended here now (older ones were from Aircraft Spruce). 

[Runtoeat]

Chris, best to follow Matco's instructions for working on the Matco wheel and especially reinstalling the wheel.  The Matco bearing is different than a standard bearing.  The bearing has a rubber dust seal which is supposed to stay with the bearing and remain stationary on the bearing and allow the wheel to turn around this stationary seal when the wheel rotates.  This requires one to tighten the bearing retaining nut tighter than a standard bearing is tightened so the seal is held stationary to the bearing.  This is done to increase the life of the seal. 

Matco bearing install.pdf

[Chris S.]

12 hours ago, Runtoeat said:

Chris, best to follow Matco's instructions for working on the Matco wheel and especially reinstalling the wheel.  The Matco bearing is different than a standard bearing.  The bearing has a rubber dust seal which is supposed to stay with the bearing and remain stationary on the bearing and allow the wheel to turn around this stationary seal when the wheel rotates.  This requires one to tighten the bearing retaining nut tighter than a standard bearing is tightened so the seal is held stationary to the bearing.  This is done to increase the life of the seal. 

Matco bearing install.pdf 56.4 kB · 4 downloads

This is a great tip and thanks for the guide. When I first put it back on and tightened up it didn't feel right being so tight so I propped up the other side to check since I haven't touched that one and it was also very tight/not rotating freely so I tightened up the new one to match. Good to see the official guidance, I may go back and tweak it a bit more. Haven't noticed any vibration yet but if I do I will also follow @GrassStripFlyBoy's advice with the balancing. 

[Runtoeat]

Those who opt for the Desser 6.00x4 "monster" tires are probably those who will really want to check the wheel balance.  I am one who uses these tires.  They are very heavy and probably will need balancing.   If your tires are out of balance, you will notice a shake after lifting off which can be cancelled by momentarily applying the brakes.  I'm trying to stay away from purchasing anything Chinese but purchased the Harbor Freight balancer before my change in attitude.  Roger Lee has provided information on the balancer he uses elsewhere on our forum and I would recommend this.