Replacing shock discs

[Marc_B]

I've always heard shock life span 5-7 yrs for long bodies, and 12-15 yrs for short/mid bodies.  What is everyone typically getting for life cycle from new to out of spec in the real world?

[Mooneymite]

19 minutes ago, Marc_B said:

I've always heard shock life span 5-7 yrs for long bodies, and 12-15 yrs for short/mid bodies.  What is everyone typically getting for life cycle from new to out of spec in the real world?

Mine were well beyond 20 years old on my hangared C model.  When the right gear approached limits, I replaced all the doughnuts and to tell you the truth, I wish I'd waited several more years.  I can tell almost no difference in ride either on asphalt, or our turf runway.  The short bodies just don't seem to wear out the shock discs like the heavier models do.  I'm not sure if keeping the plane in a hangar is significant.

[Oscar Avalle]

I just replaced mine after about 15 years. The main gear ones were sour of specs not the front one. But I did all of them. Did I notice a difference? Not really

Óscar


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[Wildhorsetrail]

2 hours ago, MV Aviation said:

I’ve done my mains according to the way suggested here. It worked pretty well despite the fact that the collar bolts were put in the wrong way last time, which made it impossible to remove them without disassembling the gear doors. I recorded a little time laps…

IMG_0867.MOV

Nice video. Which I could work that fast. 

[David Lloyd]

Picked up my C at AGL Aviation today, a friend gave me a ride in his F, dropping it for an annual inspection.  This year he is having the original 1976 discs replaced.  For the last couple years, cold mornings, sometimes the gear would not come up unless the bypass was pushed. Recently it has been every cold morning.  
Lynn and Tamara met us this morning, while there another Mooney was being dropped off.  Lynn took care of a problem for me in just a few minutes that three other shops did not understand what or want to do.  It is refreshing to deal with someone like Lynn that actually cares about doing a good job.

[Shadrach]

Can confirm that I feel no seat of the pants difference between old and new.

[carusoam]

Nice video MV!

-a-

[outermarker]

I just called Aircraft Spruce about the availability of disks. They have plenty, however, they don't have 11 from the same lot. There is six months difference or more of what they have. Since they have so many, they will not be ordering a fresh lot. Does it matter if the disks are from multiple lots but all in the same year?

[LANCECASPER]

4 hours ago, outermarker said:

I just called Aircraft Spruce about the availability of disks. They have plenty, however, they don't have 11 from the same lot. There is six months difference or more of what they have. Since they have so many, they will not be ordering a fresh lot. Does it matter if the disks are from multiple lots but all in the same year?

Makes no difference whatsoever. If you looked at the Mooney fleet, if all of the replacement discs on any one airplane were all from the same lot it would be completely by coincidence.

[outermarker]

that is a bit of relief. thanks! 

 

[bruce_m20e]

On 3/19/2016 at 1:17 PM, 1524J said:

In trying to add photos I managed to somehow delete the thread.....technological disability rearing its ugly head. Anyhow here's photos I promised but couldn't take with greasy hands.

Is there a chance to get these pictures as they are not showing up

[bruce_m20e]

On 3/19/2016 at 1:17 PM, 1524J said:

In trying to add photos I managed to somehow delete the thread.....technological disability rearing its ugly head. Anyhow here's photos I promised but couldn't take with greasy hands.

Is there a chance to get these pictures as they are not showing up

[RoundTwo]

3 hours ago, bruce_m20e said:

Is there a chance to get these pictures as they are not showing up

Since those were from 2016, that was before moving to the latest servers, so probably not. Most likely someone has some pictures available they can post.

[Joe Linnebur]

I’ll be changing out ours in Aug. Looking at the service manual and elsewhere, I don’t see any specific torque settings for the bolts (although I’m not quite sure it’s even possible to get one in those tight places). Any feedback on this, or am I missing something? 

[OR75]

1 hour ago, Joe Linnebur said:

I’ll be changing out ours in Aug. Looking at the service manual and elsewhere, I don’t see any specific torque settings for the bolts (although I’m not quite sure it’s even possible to get one in those tight places). Any feedback on this, or am I missing something? 

Chapter 5 of the service manual has the torque values 

[Joe Linnebur]

9 hours ago, OR75 said:

Chapter 5 of the service manual has the torque values 

Awesome, thank you! 

[rickseeman]

On 4/9/2022 at 5:06 PM, Shadrach said:

Can confirm that I feel no seat of the pants difference between old and new.

I can't say that. My right buttock is sitting about $3,500 lower.

[bruce_m20e]

On 4/9/2022 at 2:06 PM, Shadrach said:

Can confirm that I feel no seat of the pants difference between old and new.

After changing, can confirm, I feel no difference in landing softness. But can confirm, the discs were harder than a rock and more slop than a sloppy joe

 

 

 

.....Our landings must be that good

 

 

 

 

Edited July 20, 2023 by bruce_m20e

[Shadrach]

On 7/20/2023 at 3:22 PM, bruce_m20e said:

After changing, can confirm, I feel no difference in landing softness. But can confirm, the discs were harder than a rock and more slop than a sloppy joe

 

 

 

.....Our landings must be that good

 

 

 

 

The thing is, mine were not hard. They were a compressed slightly but still easily compressed in a vice. They continued to pass the twist test except for in the freezing cold which prompted me to replaced them.

Edited July 25, 2023 by Shadrach

[RobertGary1]

On 7/20/2023 at 12:22 PM, bruce_m20e said:

After changing, can confirm, I feel no difference in landing softness. But can confirm, the discs were harder than a rock and more slop than a sloppy joe

 

 

 

.....Our landings must be that good

 

 

 

 

Me too. No difference in ride or in landing. I changed mine because they were worn enough that only gravity dropped the gear done for the unsquat switch. A couple failed retractions in the winter made it worth it. 
I was surprised that swapping them was a lot earlier than I’d thought. The access hole didn’t line up well with the top bolt but other than that it was pretty straight foreword. Even with empty tanks I had no issues compressing the mains just with weight. 

[AndreiC]

If anyone has photos of how the replacement process works, it would be greatly appreciated if they'd post (re-post?) them here. The old ones don't show any more.

Also, is this something that can be legally done by the owner, or is this what should be part of the owner-assisted annual?

[Fly Boomer]

1 hour ago, Andrei Caldararu said:

If anyone has photos of how the replacement process works, it would be greatly appreciated if they'd post (re-post?) them here. The old ones don't show any more.

Also, is this something that can be legally done by the owner, or is this what should be part of the owner-assisted annual?

I’m hoping someone re-posts some good pictures and procedures.  If you get desperate, I have some posts saved, but not well organized.

[A64Pilot]

1 hour ago, Andrei Caldararu said:

Also, is this something that can be legally done by the owner, or is this what should be part of the owner-assisted annual?

I’m an IA and my opinion is the FAA would say no, but I can’t come up with a logical reason why your allowed to replace a tire under preventative maintenance but not rubber shock disks.

I think in truth the answer is that’s it’s always been that way. I think one inspector would say it’s OK and another have a fit

A little reading that may help?

I think as usual it falls to you to decide what you can and cannot do.

https://www.faasafety.gov/files/gslac/library/documents/2011/Aug/56398/FAA P-8740-15 Maintenance Aspects of Owning Your Own Aircraft [hi-res] branded.pdf

https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_43-12A_CHG_1.pdf

Also FAA part 43, Appendix A sub paragraph c gives you a list

Edited July 24, 2023 by A64Pilot

[RobertGary1]

3 hours ago, Andrei Caldararu said:

Also, is this something that can be legally done by the owner, or is this what should be part of the owner-assisted annual?

I really don't think so. However just offer the local IA $100 to stop by for a few minutes to review your work?

 

-Robert

[DCarlton]

On 7/20/2023 at 12:32 PM, Shadrach said:

The thing is, mine were not hard. They were a compressed slightly but still easily compressed in a vice. They continued to pass the twist test except for in the cold prompting me to replaced them.

Getting my tanks sealed in Sep and wondered if I should have the disks checked.  I’m not feeling a strong argument to do it in this thread.  ???