Laning gear shock discs replacement

[M20R]

I checked my landing gear shock discs and all appear to need replacement. I know the discs are a little over a hundred bucks each but how much labor is involved? I am currently in Florida, can anyone suggest some place to have them replaced? Thanks

[Raptor05121]

Where in FL are you?

[M20R]

Gainesville, FL

[carusoam]

R,

Feel free to put a photo or add some data to your avatar....  It will help us to help you!

Best regards,

-a-

[Rustler]

M20R--

Just had my donuts done in April. $1300 for the donuts, $360 (less than 4 hours) for the labor.

 

 

[StevenL757]

Seconded.  Had my nose gear biscuits done last annual, and mains will be this year.  LASAR used to come in under $100 apiece, but given price increases over the last year or so, Michael's cost is right on.

As far as where to have them done, if your mechanic has the specific tool to aid in their replacement and has done them before, then agree 4 hours should be about right.  If he doesn't have the tool, it might add add an hour.  Best to locate the tool, or go to someone who has it, or could loan it to you.  Generally speaking, Michael's experiences and mine seem to align, so unless issues are encountered, I'd expect those times and numbers in your case.

My mechanic borrows one from another place on the field where I go for annual, so if you haven't located one, I can ask him...he seems to know where a few are strategically located around the South, so let me know if you're struggling with this and I can ask.

Regards, Steve

[1524J]

Search "Replacing Shock discs" on Mooney Space. Not difficult if you have an A&P willing to work with you. 

[StevenL757]

Wow.  Yeah, didn't think to look there of all places.  That beats Aviall by a few dollars...and Spruce will ship free over $500.

[kortopates]

Only need the special tool to do the nose wheel. Weight on mains is sufficient to compress the mains and it's faster that way. Be sure to inspect the inside bottom of the tower that holds them though since corrosion is very common there. LASAR sells rebuilt ones if you need them.

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[Yooper Rocketman]

I just replaced my 20 year old pucks on the mains, even though they looked good, but found the gap between the retainer ring at the top and the mount to be about 1/2" when down on the gear (manual called for .060" or 1/16")  I bought them from Don Maxwell, as he was good enough to send me some o-rings the day before that were more work to dig up and package than he clearly made selling them to me..  Anyway, after getting the new ones in I dropped the plane back down on the gear and had the same 1/2" gap????  While talking to my IA this AM, as he was inspecting my owner "assisted" annual (I did most of the annual), I told him about my frustration in dropping $800 plus for nothing, as the gap didn't change at the top and was still out of spec.  As I told him about it, I decided to look it up in the book again to show him, and found the dimension is .60", which is almost 5/8"...................dah.   I saw on this list someone saying ANY gap is grounds for replacement.  That is not what the Mooney Manual says, and likely not what you will get, even with new pucks.

Tom

[kortopates]

I believe what they were saying is that after you jack the plane up off the wheels any gap should be gone or absorbed by the rubber expanding such that you can not rotate the disk with your hands. That is correct and another indicator in addition to the compressed gap as shown in the manual. The manual does not cover the uncompressed gap (as not having any) but it is a very popular indicator used by Mooney savvy tech's and perhaps actually better than the manual compressed method since it directly tells you if the disk still have the resiliency to expand. Both are valid indications.

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Edited May 27, 2016 by kortopates
spelling

[Hank]

The increasing frequency and duration if partly-retracted gear in the winter convinced me. Nothing like flying 15-20 minutes with the gear horn buzzing and "unsafe" light lit, waiting for the last few inches of retraction. Eleven new pucks one December fixed that!

[carusoam]

There are some photos around here showing stacks of biscuits, new vs. old, setting on a table.

The old ones get shorter and expand or get squeezed outwards.  Time, temperature and pressure work their evils...

Rubber is like a very high viscosity polymer.  It flows in a timeframe measured in years.  Slightly quicker than glass' flow rate that can be measured in centuries.

Simple PP ideas, I am not a mechanic...

Best regards,

-a-

[PMcClure]

You can rent the tool from Laser for $50. FYI

 

[ArtVandelay]

There are some photos around here showing stacks of biscuits, new vs. old, setting on a table.

The old ones get shorter and expand or get squeezed outwards.  Time, temperature and pressure work their evils...

Rubber is like a very high viscosity polymer.  It flows in a timeframe measured in years.  Slightly quicker than glass' flow rate that can be measured in centuries.

Simple PP ideas, I am not a mechanic...

Best regards,

-a-

And probably the heavier models require more frequent replacement.

[Yooper Rocketman]

Mine had no gap when the plane was raised on the jacks.  The difference between the new and old pucks stacked on a table side by side was minimal, not like any of the previous pictures I had seen on this site.  Guess that's one advantage to storing the plane (in a hangar) without the tanks filled for the last 16 years.

[N201MKTurbo]

When people say there should be no gap when jacked up, they don't mean between the center shaft collar and the top plate, they mean between the plate that sits on top of the pucks, with the anti rotation bar, and the fixed top plate.

It just means that the pucks should expand and fill up all the space with the gear hanging. If it doesn't then when you take off and land the anti-rotation plate can rotate, and that defeats its purpose and makes it mad.

[Mooneymite]

Aircraft Spruce just raised the price of the discs:  $113.85 each.  

Spruce agreed to match a lower price I found ($102).  Aircraft Spruce is local for me, so saving the postage is an added benefit.

[kortopates]

On 5/27/2016 at 6:09 AM, Yooper Rocketman said:

Mine had no gap when the plane was raised on the jacks.  The difference between the new and old pucks stacked on a table side by side was minimal, not like any of the previous pictures I had seen on this site.  Guess that's one advantage to storing the plane (in a hangar) without the tanks filled for the last 16 years.

Mine seem to last about 8 years, also hangared, and yours is a little heavier with the rocket conversion. I'd be surprised if you don't feel it taxi smoother with the new disk. 20 years should be way past due; especially for a rubber product. 

[FoxMike]

I just put the second set of donuts on my Bravo at 1750TT.  My plane is hangared but usually has more than 80 gals in the tanks.  The airplane is normally sitting in the hangar loaded to about 2800+ lbs crushing the donuts.  I sure wish Mooney would have taken Bill Wheats advice and put the Mustang wing on the bigger airframes so they could get away from the donuts.

Edited May 28, 2016 by FoxMike
forgot a word

[1524J]

3 hours ago, FoxMike said:

I just put the second set of donuts on my Bravo at 1750TT.  My plane is hangared but usually has more than 80 gals in the tanks.  The airplane is normally sitting in the hangar loaded to about 2800+ lbs crushing the donuts.  I sure wish Mooney would have taken Bill Wheats advice and put the Mustang wing on the bigger airframes so they could get away from the donuts.

You guys with the heavier load might benefit from using Lasars tie down/jack point combination and have a set of jacks ready to take some of the load off while static. 

[carusoam]

Being indoors helps with protection from UV light, and moderating temperatures.  But doesn't give much relief to the compressing rubber.

leaving tanks empty and jacking up the plane would supply relief but then the cost putting in that much effort increases.

one of these days somebody in the airplane suspension world is going to come up with an improved biscuit...

Best regards,

-a-

[AZ231]

On 5/27/2016 at 7:00 AM, Mooneymite said:

Aircraft Spruce just raised the price of the discs:  $113.85 each.  

Spruce agreed to match a lower price I found ($102).  Aircraft Spruce is local for me, so saving the postage is an added benefit.

I'll have to go Aircraft Spruce for my mains at the next annual. Just replaced my front discs and the shop billed $140 each, plus labor. Definitely pays to shop around if the shop will allow owner-supplied parts.

[Mooneymite]

When you're buying 11, it makes quite a difference.

But airplane owners are frivolous with their money, so sock it to 'em!  

[jetdriven]

I just bought 8.  The Nose gear ones have very little weight on them and they are still highly compressed when installed. 

Edited May 31, 2016 by jetdriven