BettyFord

new bearings every annual

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Hi, every annual my maintenance is replacing 1 or 2 wheel bearings? The ac is flying 50-70hrs a year. Are the bearings so weak or what is the problem. (M20J 1995)

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if you are replacing wheel bearings that often something is wrong and your shop should be looking for the cause. there are 2 wheel bearings per wheel so 6 bearings total for the aircraft. when i change bearings I change both bearing/race combination in the wheel at the same time, I would check your logs to see what bearings have been replaced and if any of them are repeats or if they are on different wheels.

Brian

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One of two things in my experience cause wheel bearings to prematurely fail: corrosion (Parked outside / exposure to rain snow, etc) or ... over torqued axle nut. 

If your plane doesn’t roll easily on a flat surface and your calipers release then your axle nut is over torqued and your bearings will eventually fail. 

PP only etc. 

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2 minutes ago, bradp said:

One of two things in my experience cause wheel bearings to prematurely fail: corrosion (Parked outside / exposure to rain snow, etc) or ... over torqued axle nut. 

If your plane doesn’t roll easily on a flat surface and your calipers release then your axle nut is over torqued and your bearings will eventually fail. 

PP only etc. 

under torqued is just as bad, or there could be missing or damaged spacers.

Brian

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The first few years of ownership this is normal. Those bearing could be decades old.  But I wouldn’t expect to change the same one twice. 

-Robert 

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Does the plane actually fly, or are you taxiing it all those hours?

Unless you taxi extensively, or there is something wrong with your wheels, annual bearing replacement is crazy.

Can you send me your "old bearings"?  I bet they're in better shape than the ones I've been running on for 20 years!

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Do you get the old bearings handed to you ?  If not you're getting hosed - make that a condition of payment - 

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4 hours ago, BettyFord said:

Hi, every annual my maintenance is replacing 1 or 2 wheel bearings? The ac is flying 50-70hrs a year. Are the bearings so weak or what is the problem. (M20J 1995)

It seems unusual to replace that many wheel bearings.  Are they greasing them when they replace them?

Clarence

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So let's say all 6 were looking a little pitted, but still had some life in them. Your mechanic may have replaced the two worst ones. The next year he looked at them again and replaced two more. 

He may just be doing you a favor by spreading the pain over a few years.

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6 minutes ago, N201MKTurbo said:

So let's say all 6 were looking a little pitted, but still had some life in them. Your mechanic may have replaced the two worst ones. The next year he looked at them again and replaced two more. 

He may just be doing you a favor by spreading the pain over a few years.

This brings up a pet peeve of mine, mechanics/avionics shops seem to suck at communicating.  You basically have to interrogate them about what they do and why are they doing it.

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13 minutes ago, teejayevans said:

This brings up a pet peeve of mine, mechanics/avionics shops seem to suck at communicating.  You basically have to interrogate them about what they do and why are they doing it.

Depends on your mechanic. I try to give all the info to the owners who’s airplanes I work on. 

Brian

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^^ can confirm - this is one of the many reasons Brian is a cut above the rest. 

I think a lot of it comes from those A&Ps who are also pilots and treat you the way they would want to be treated if someone was working on their airplanes. They understand the cost of ownership which makes them worth a premium in my eyes. 

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If the airplane is tied out, it is common to have the NLG wheel bearing(s) corrode over the course of a year. They are exposed. I guess I would not expect that in a desert environment but anywhere it rains.

 

Edited by Immelman
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1 hour ago, Immelman said:

 

If the airplane is tied out, it is common to have the NLG wheel bearing(s) corrode over the course of a year. They are exposed. I guess I would not expect that in a desert environment but anywhere it rains.

 

 If you keep fresh grease on them annually they shouldn’t have contact with corrosives  

-Rober 

Edited by RobertGary1

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Do the wheels have the old felt seals or the newer molded seals? I had a '78J years ago with felt seals that sat outside, and every year the main wheel bearing races would show corrosion at some point around the circumference. Try changing the seals if you have felt.

Skip

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I don't taxi more than other....and the aircraft is hangered since it was produced. It was my first annual, but the previous owner had changed bearings also every year with the same maintenance place. Could the gras airport be the problem? Surface is smooth though.

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3 hours ago, BettyFord said:

I don't taxi more than other....and the aircraft is hangered since it was produced. It was my first annual, but the previous owner had changed bearings also every year with the same maintenance place. Could the gras airport be the problem? Surface is smooth though.

It does seem odd.  Did the shop show you the bearing they replaced during your annual inspection?

 I take care of numerous airplanes that are parked outside, they don’t experience wheel bearing replacement more than any other and certainly not annually.

I would be asking what grease they are using? And are they using enough of it?

Clarence

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I keep my plane in a hangar on a grass strip and I have not changed the bearings in the 5 years I have owned it and these were the bearings in there when I bought it.  Clean and grease them  every year but we do not change them.

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2 hours ago, M20Doc said:

It does seem odd.  Did the shop show you the bearing they replaced during your annual inspection?

 I take care of numerous airplanes that are parked outside, they don’t experience wheel bearing replacement more than any other and certainly not annually.

I would be asking what grease they are using? And are they using enough of it?

Clarence

 

5 hours ago, BettyFord said:

I don't taxi more than other....and the aircraft is hangered since it was produced. It was my first annual, but the previous owner had changed bearings also every year with the same maintenance place. Could the gras airport be the problem? Surface is smooth though.

Nothing against the shop that has been doing the annuals, but you may consider another shop for the next annual. I personally recommend that the owners take the planes I look at to some one else every couple of years just to get another set of eyes on the plane. I try to be though but I can miss things someone else will catch and vice versa. I especially have someone else take a look at my plane because I know it so well and can easily overlook the obvious.

Brian

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12 hours ago, PT20J said:

Do the wheels have the old felt seals or the newer molded seals? I had a '78J years ago with felt seals that sat outside, and every year the main wheel bearing races would show corrosion at some point around the circumference. Try changing the seals if you have felt.

Skip

Do you have any info on the molded seals? I would much prefer these to the felt that we have

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^ plus one on Byron's post.  I've always thought it a bit ridiculous to have a water retaining seal in an area exposed to the elements.

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5 hours ago, jetdriven said:

Do you have any info on the molded seals? I would much prefer these to the felt that we have

Does this help?

 

6B3C6E1D-C48D-4CAB-8F5B-8898AD5F45AF.png

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sure they are not just "packing"  instead of replacing?   Maybe just a habit the mechanic got into.  It would remove any doubt that they are airworthy.

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No.  Item 12 on the upper part of the drawing is still a felt part. I have that now. Looking to rid. 

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