McCauley wheel question.

[Gary Ward]

6.00-6" wheels on my mains on a 172 can they get bent during use?
I have one that the rotor will not run true. I have had it off and inspected and see no issue other than the brake rotor does not run true. It is not the rotor because I swapped in a new rotor and it still does not run true. Are those wheels known to bend like on turf runways?
TIA

 

[Bell206]

6.00-6" wheels on my mains on a 172 can they get bent during use?

Can't say I've seen them bent as you describe. What is the P/N for the wheel? What are you using for your reference to determine how the wheel/disc tracks?

 

[Salty]

Yeah, what does "rotor will not run true" mean exactly?

 

[Dan Thomas]

Those wheels tend to break rather than bend. If the wheel is off-true, so will its bearings be. You might need to put the wheel alone on the axle, no disc, put the nut on, and then use a dial gauge on a suitable stand to measure the runout of the wheel's disc mating surface.

You didn't forget a washer on one wheel bolt that got trapped under the disc, did you?

And you didn't get the tire tube caught between the wheel halves, spreading them at one point?

Are these the old three-piece McCauleys with the steel rims? Or the all-aluminum or magnesium wheels? The three-piece affairs had a habit of cracking at the threaded rim bolt holes, and maybe a small chunk of the aluminum hub broke out and got trapped between the rim and hub.

 

[Gary Ward]

Thanks for the response.
It is a mcCauley 2 piece wheel D30662 D30657 wheel halves.
I noticed the disc rubbing the brake pads when moving the plane it seemed all of a sudden? Or at least I started to notice it.
This was last year or so. Earlier this year I took the wheel off and apart and didn't find any cracks or apparent damage. Put it back together and spun the wheel and rotor by hand on the spindle and can see the brake disc is not true. I had a set of new rotors in stock waiting for the next brake job so I bolted on a new one and spun it by hand, same thing the rotor is not true. I took it off and put the used rotor back on. This was months ago and have been using it like that. But it makes noise as I taxi or move the plane and want it fixed if I sell the plane one of these days.
I don't remember this being a problem when I first started flying the plane. It has been landed on some rough turf strips a lot in the last 3 years. I have replaced the brake pad and rotors once before and didn't notice a problem.

The outer rim is true just not the rotor. I thought about trying to shim the rotor but would not do that without a AP saying it ok to try.

I cleaned it up and made sure the bearing races were seated in the wheel. Weird deal hoping for some ideas before I buy a used wheel.

 

[Magman]

There is a Cleveland Conversion Kit specifically for your aircraft.

My experience with the 3 piece units and the issues Dan mentioned puts them at

a very low point in the ratings. My preference is staying on the runway when

landing. Hard to do that with a broken wheel!

The 2 piece were a definite improvement though till not equivalent to Cleveland’s.

Anyone staying with McCauley should assure the insurance is maxed out.

 

[Jdm]

I’ve run into this with the old McCauley 172’s. My guess is it’s the caliper. Just recently replaced worn disks and linings myself. Still had trouble. Actually it got worse. The magnesium calipers tend to warp, possibly from over tightening. Also slide holes and pins become worn. The combination of all this can make it difficult to figure out. You can try swapping backing plates with the other side, etc for trouble shooting. I’ve even used emery cloth on a flat surface to help shape things back true once confirmed.
Ultimately, I ordered a different brand of linings. This helped more than anything. I confirmed a significant variation in new linings between two major manufacturers.
If you have recently replaced linings this could be your problem. I have info at the hanger on the brand that I’ve found to work best with the old McCauley calipers. The ultimate fix is upgrading to Cleavlands

 

[Magman]

The Torque Plate often distorts. It can be observed if the face of the caliper is/ is not parallel to the disc.

As is previous post the lining may make a difference with disc wear. Leaving a ridge will tend to produce uneven with a new lining . Cleves can do that too.

There were other manufacturers that produced wheels/brakes for light aircraft.
Some were horror stories.

 

[Jdm]

I’m at the hanger looking at linings from RAPCO and APS side by side. Both P/N are for the same application. C172 w/McCauley’s
RAPCO’s are thicker and not quite as long. Both fit but I’ve had much better luck with APS for this application.