Nose Wheel Hub Cracks

[Warren Janzen]

Just pulled apart my nose wheel on a 180 for paint purposes. The back lip that stops the bearing race of the hub is cracked. I assume this is not something that I can let slide. The cracks don't go all the way through but if the races cave into center, it could cause an accident.
Any suggestions? Part number? Is the nose wheel rim unique to the Comanche or will other Piper models substitute?


Thanks Warren

[Charles Schefer]

Warren,

Even zoomed in I can't tell from your pics if you have actual cracks or if you are just looking at rough imperfections in the casting. The wheel is a Cleveland 38501 which Cleveland also ties to a 40-8 and this is Piper P/N 451 755. It's the same nose wheel used on many single and twin Comanches. It is a magnesium alloy wheel, different from the mains. Here are some pics from the PA-24 IPC and the Cleveland manual below. You can get the IPC from the ICS Technical Docs posted from the main site. They are old documents but worth having and relatively easy to use.

I'd start by verifying 100% that you have cracks and aren't just being fooled by the casting marks. Have a shop capable of doing such checks take a look at it maybe with dye penetrant or magnaflux (if they can do that on mag wheels). If you do have cracks, then no... I wouldn't let it go that way or you will end up with a much more expensive repair down the road. I'd call Matt Kurke at and see if he has a spare. I bought a 38501 from Matt a year ago when I did my gear overhaul (my original was pitted). I've also seen full assemblies for sale on eBay.

Here are some pics from the manuals...

Here is the Nose Wheel Assembly Pic...

Here is the Parts Listing...

There are two possible nose wheels but based on the notes "V" only applies to 24-260s and "A" applies to 180s hence it looks like you have the 38501 model...

Here is pic from the Cleveland Manual which shows the 38501 ties over to the 40-8 (and also gives you the torque spec)...

Hope all this helps. I remember being a bit confused by all the numbers and references when I had to do my nose wheel a year ago so I hope this helps clarify. Moreover I hope your nose wheel is not actually cracked! In painting your wheel (existing or replacement) do remember it is a Magnesium Alloy NOT Aluminum which means you cannot acid etch it or use Allodine.

Best,

- Charles

[James Turner]

Hi Charles,

Sorry to hijack this thread but are you able to confirm for me that the main wheel assemblies are magnesium alloy also and that alodine should not be used on those either?

I'm referring specifically to 40-5 mains on a -180?

Many thanks,

James.

P.S. Warren; the main wheel that I have recently disassembled looks similar. My engineer, after a close inspection was satisfied that the marks were from the casting. FWIW..

[Warren Janzen]

Charles, thanks for your input and reference info. James your info helps too. I've looked at them closer. I do believe a lot of the roughness is from the casting. Also, some corrosion & pitting also make it look possibly worse than it actually is. I want to clean them up some more. Can these rims be sand blasted with fine sand or is that a bad idea? I've got the bearing races removed. I don't know how else to get them cleaned up effectively. Can't use acid, hot tanks, or lacquer thinner correct?

Warren

[James Turner]

Hi Warren,

Not sure if it helps but with my main wheel I bead blasted it then alodined it (yep.. yikes!) then chromated it then painted it.

Gulp...

James.

P.S. It looked fine after bead blasting...

[Charles Schefer]

James - Fear Not. Your main wheels are most probably Aluminum so Alodine should be no problem there. On my twin the main wheel is a Cleveland 40-90 and it is definitely Aluminum. I think Magnesium Alloy was only used on the nose wheel. See additional notes below where I posted the IPC for the main wheel.

There is also no problem with glass beading parts, just be careful. Glass beading is abrasive and you don't want to wear things down too much. That said I am a big fan of glass beading. I actually just came back from the garage where I was glass beading my engine valve covers which I am in the process of refinishing. The thing to be careful of if glass beading aluminum is that you do not want to use any grit that has silica in it (same goes for sandpaper). A little knowledge I picked up from Zach Grant; silica sets up a galvanic reaction with aluminum and promotes corrosion. If you've used a glass beaded is is most likely that the material used in the machine does NOT have silica so you would be safe. I know when we buy material for our blaster the packages are marked silica-free. If you are using an actual "sand blaster" that is normally used out doors with regular sand - well that's a different story and I wouldn't recommend that.

I would NOT hot tank any of these wheels. Also - you mentioned your bearings are removed and that's good. Obviously glass beading would not be good on bearings. Just make sure you clean them very well after. Blow them out with compressed air, wash them, use a mild solvent, and dry them well. Paint them and then put the races back in (don't paint in where the races go - tolerances are too tight).

Warren - It really would not surprise me if what you are looking at is just lines from the casting. However, regarding "pitting" do be careful of that. My original 38501 wheel had too much pitting to be reused which is why I bought a new one (well - a good used one) from Matt Kurke.

Here are a few pics related to your (Warren / James) follow-up posts...

From the PA-24 IPC is a figure of the MAIN wheel...

Here is the parts description for the main wheel from the IPC. It looks like there were a number of wheel types used on PA-24 aircraft. I see from the IPC the Cleveland 40-90 (the main wheel I have on my PA-30) was also used on the 24-260. Again this is an aluminum wheel. I could be wrong but I think all main wheels were probably aluminum. I'd use the pic below and your S/N to figure out what model of main wheel you have and then contact Cleveland to find out what alloy it is made of to be sure. My guess would be aluminum. Magnesium is very soft but light so they used it on the nose wheel but I really don't think they would for the mains - again I'd verify to be sure using your S/N, the IPC below and a call to Cleveland. EDIT - Sorry James you indicated you have a 40-5. Not sure about that one but I'd call Cleveland. If I had go guess I'd bet it's aluminum.

Here's a pic of my old 38501 after I glass beaded it. Notice the pitting.. this was too much pitting for reuse in my book and in the minds of the IAs I was working with. The 145 repair station / paint shop I used for Alodine / Aluminum work said they wouldn't even paint if I asked them because they felt it was way too pitted. It also had strange abrasion around the rim as you can see.

Hope this helps. For more expert advice than I can offer I really would call Matt Kurke at Comanche Gear. He is the Oracle when it comes to Comanche Landing Gear.

- Charles

[Charles Schefer]

PS - Laquer Thinner won't hurt anything. Mineral Spirits (aka "Stoddard Solvent") is a wonderful general cleaner for machinery. I use it liberally in cleaning out under panels, in the tail cone, engines during annual, etc... Just know that if you plan to paint you will then need to use wax and grease remover to remove the Mineral Spirits.

- Charles

[Kristin Winter]

According to Cleveland's Service Manual, quite a few of the wheels are magnesium. The 40-90 is listed as magnesium. See page 14 of the attached, assuming this is still a current manual.

[Charles Schefer]

Interesting!!!

Thanks Kristin. Attached is the copy of the Cleveland manual I downloaded (I thought) from the Parker site a year ago. It does not list the metal type with each wheel nor does it have revision info at the front. However upon closer inspection at the very end of the document it is revision F dated 2000 and your copy is dated 2006 which is obviously more current.

The strange thing here is I called Parker Cleveland a year ago about this very issue and they insisted the 40-90 was aluminum. The fellow I talked to said they had too many issues with the mag wheels and had gone to aluminum some time ago. That said, your 2006 manual still lists it as magnesium!

When I stripped all my wheels to bare metal the nose wheel was clearly a very different metal. Side by side they looked totally different and the 145 Repair Station / Paint shop quickly identified the nose wheel as mag and the mains as aluminum. Cleveland told me the same over the phone.

So now I don't know what to think.... but your manual is the most current one I've seen and it clearly says magnesium and to me that is compelling.

- Charles

WHEEL and BRAKE svc guide.pdf

(228.37 KiB) Downloaded 114 times

[James Turner]

Thanks guys.

From the service manual it looks like the 40-5 (3070) is magnesium. Hope I haven't wrecked it...

Any advice on what to do with it now would be appreciated.

Cheers,

James.

[Charles Schefer]

James, I need to do more research on this but personally I don't think you've wrecked your wheel. My comment about not using Alodine on magnesium was based on the paint shops comments to me at the time. The tech data sheet for Alodine 1201 says it's for "aluminum and it's alloys". They Henkel has a separate Alodine product for magnesium. I actually don't see anything one way or another in the 1201 data sheet with regard to magnesium but it's clearly targeted at aluminum (and alloys).

Doing some quick research on-line I've found quite a few automotive references (Ferrari Club, Porsche Club) where people have used (and advocate) Alumaprep 33 and Alodine 1201 on magnesium car wheels. I wouldn't recommend that but you can find those references on line.

I am going to try to find some time to call Cleveland again and perhaps Henkel to pull the thread on this.

- Chalres

PS - I've attached the tech data sheets for Alodine 1201 and for Henkel's mag treatment product.

ALODINE® 1201-EN.pdf

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ALODINE-MAGNESIUM-TREATMENT-KIT-ds.pdf

(124.43 KiB) Downloaded 108 times

[James Turner]

Thanks Charles and sorry again Warren for hijacking your thread.. Hope you get a good result on your wheel rim question.

Cheers,

James.

[Kristin Winter]

Charles,

I am surprised that there is a discrepancy between the manual and what the tech folks were telling you. Based on the manual, I treated my main wheels with the recommended magnesium treatment. Now I am wondering if I treated them with the wrong thing. They didn't seem to color the way they were supposed to, so perhaps mine were aluminum after all. Let us know if you find out anything further.

[Charles Schefer]

Kristin, I strongly suspect your info is correct. I have a hard time believing a published manual would be wrong that way... well what I mean is I think it is more likely that one person I talked to was wrong vs the manual being incorrect.

That said, the paint shop I used was not only a paint shop but a very experienced fabrication shop (I saw them building entire new wings for a light twin). The guy there who did some aluminium fabrication for me has been doing aluminum work since 1968. They insisted my main wheels (40-90) were aluminum. Here's another interesting datapoint... my main 40-90 wheels are the same size as my 38501 nose wheel BUT... each main wheel was 2-3 times heavier than the nose wheel. I couldn't believe how big a diffference there was and that reaffirmed (to me at the time) that my mains were aluminum and the nose wheel magnesium.

I'll try to call Parker and Henkel today. I just didn't have time yesterday. I'm in the middle of yet another big annual on my Twin and my work schedule is hectic so I'm back and forth between the hangar and offfice area.

- Charles

[Charles Schefer]

Sorry for the delay in following up on this. I was out of town for awhile and had time to make a few quick posts but not to research this item until now.

Today I started by calling Parker-Cleveland Tech Support at (440) 937-6211. I spoke to "Sandy" and explained the question. I explained that my 38501 (40-8) which IS magnesium is much lighter than my main 40-90 wheels and I had been told by Cleveland, and other sources that the 40-90 mains were aluminum. Not so according to Sandy. Kristin is correct, the 40-90 wheels are magnesium according to Cleveland. Sandy checked all revisions and said the 40-90 "A" thru "F" all show as magnesium wheels. I asked why they were heavier than the 38501 nose wheel and she said they shouldn't be. So... maybe I'm just wrong about the weight difference (perception vs reality). Anyway it seems that the main wheels are magnesium.

My next call was to Henkel who make coating products including Alodine 1201. I called their tech line at (925) 458-8000 and pressed the menu buttons for coatings tech support including Alodine. That took me to someone's voicemail. I left a message and asked for a call back which I am still at this point waiting for. I want to ask Henkel what ill effects may occur (if any) if Alodine 1201 is in fact used on Magnesium.

I'll report back with what more I learn.

- Charles