Lord Shock Disc Retrofit

[troy520]

Hello,  Undertaking the retrofit on a '65 M-20E.  Hoping some folks have done this before and have some hints/tips/tricks.  Two questions I have are how to gain access to the main gear disc link top collars.  They are inside a metal box structure with a sheet metal cap.  Does this cap come off for the retrofit?  Also, I can't find any gear torque specs in the Mx manual.  Any guidance on torque or tightening specs for the gear hardware?  Thanks very much in advance!  

[sleepingsquirrel]

Hi,

Welcome to the most comprehensive Mooney site I've found. You might review : Landing gear biscuits

There are some knowledgable folks there. Thinwing may have answers.

Just don't use your wifes biscuits , it will make her very angry if she sees them on your landing gear. I was smart enough to not answer mine when she asked "what did I need all those left over biscuits for". Once they were painted black she couldn't tell.

[GeorgePerry]

lots of discussion on this topic.  Here's a link to get you started, but I'd also recommend using the search function to find answers.

 

http://www.mooneyspace.com/index.cfm?mainaction=posts&forumid=1&threadid=227

[troy520]

Thanks very much for the replies!  Thinking I've done a pretty thorough search both here and in the Mx manual and can't find any info on accessing the top collar on the mains (or removing that sheet metal piece) and on the torque specs on all the hardware.  Don't want to over-tighten the linkage bolts and put things in a bind.  Thanks again! 

[N601RX]

Welcome to the forum.  What part of Lower Alabama are you located in?  I'm in Troy, Al.  If you can't find the info you need here check the MAPA site.  A couple of the Mooney Service Centers monitor that site and usually answer mechanical questions.

[5854Q]

Hello. I am a newbie here also & happen to be taking on the replacement of the old Firsetone biscuits with Lord biscuits on my 1965 M20C. Here is what I have found so far (in addition to what has already been offered here).

Mooney SB M20-139A covers this in detail. http://www.mooney.com/servicepdf/1967.html Also SWTA sells the lord biscuits as well as LASAR (in CA.). Both rent the tool needed for this task. Another source for the tool is www.hangartoolbox.com. Everyone reccommends replacing all the hardware. The tower should be replaced if pitted or having more than very slight surface rust. The bushings can be re-used if they look good & are within specs dimensionally. I am not certain if the spacer & collar can be re-used... still checking. SWTA has a better price on the biscuits than LASAR but LASAR can make the other parts if needed (may be handy since the Mooney factory is not operating). Hope this helps.

[5854Q]

Oh, I forgot... The SB (service bulletin) identifies all the hardware needed. AC 43.13 gives the torque values for the hardware. You are right: don't over torque.

[troy520]

Thanks HUGE for the SB reference!  We have all the parts in-hand and are expecting the tool (hydraulic version) to arrive today.  I'll pass-on how it all went next week.  Oh and from the earlier post, we're in the Dothan area.  Thanks again!

[thinwing]

I am no expert,but having just changed mine out...there are a few tricks..whether using the hydraulic version or the jackscrew version (puff puff)the factory compression tools are a must...I think they must exert a 1000 lbs of force.It may be possible removing the old firestone style as they may have so lost there elastic that they will practically fall off.But compressing the new ones is a whole other matter!!!I am going to jump right to the point I predict you will run into trouble.After reassembling donots on shock towers(not in manual but spray individual disks with silacone lube..do not forget this!!!)You will than reuse compression tools to reassemble shockdiscs back onto their pivot points on landing gear trusses.Place any shims needed(especially nose gear as this affects geometry)and replace washer and retaining collar backon and retain with an bolt.Dont bother replacing nut as you will only have to take it off again if you need additional shims to correct geometry.After you remove compression tool...guess what!!!!None of the pivot bolts will perfectly lineup!!!You might get leftone started and than notice you are half a bolt off on the rightone...and these assemblys are now under 1000psi compression.After swearing and sweating you realize the manual mentions a removable alignment tool that supposed to but did not come with the compression tool/......the bullet!!!...More later..sinc kp couch

[thinwing]

ok...back with you...lets see where were we...oh yeah Troy is restoring a 65 e model...I bet they are original biscuits...just as hard and oily and cracked as the ones Sleeping Squirrel eats every morning complements of his wife.(she is angry at him for some reason and claims he spent her fancy jewelry money on a couple useless airplanes)Anyway Troy after banging his knuckles on that useless tower cap not found on late model Mooneys,is ready to rock and roll!!!.He decides to do the nose wheel biscuits first.Since this 65 e is light he decides on an engine or prop sling lift.He could invite sleeping squirrel over to help by straddling the tail,but SQs wife wont let him out of the house because he hocked her silverware and porcelain collectables for some new avionics.What to do???Well....make friends with the guy 3 hangers down with all the race cars stored away.Chances are hes got a 2 ton engine hoist  and that combined with a 2in strap will lift the front endup quicker than Paris Hiltons pushup bras!!

[sleepingsquirrel]

HI,

 My old bird could use some new avionics and it never occured to me to hock the silverware!  Is something fundamentally wrong with doubling the value of my  airplane by adding electronic gizmos? It's bad enough that filling the tanks nearly doubles its value! Forget all the special tools just put one less biscuit ,land gently.

[Alan Fox]

You can cheat the compression tools by putting the weight of the airplane on the gear , just remember to put the collar of the nosewheel on with the hole for the bolt closer to the top ... If not the steering will be impossible..... Also you definitely have to grind off the corners of the castings as outlined in the bulletin...   Also if you dont want to kill yourself putting in the retract springs , you can expand them by putting a roll of quarters in between the spring coils , just make sure you get all the quarters out of the wing when you extend the gaer and they all fall out....

[thinwing]

wow great stuff here...I totally forgot how you can expand a spring using us government mint shims!!SQ s idea of using only one biscuit is in my opinion pure genius.Al Mooney up in heaven is probably saying"now why didnt I think of That?"Saving all those biscuits could have meant a profit!!!Checkout his ad on Ebay if you need any silverware...lowest prices guaranteed..kpc

[thinwing]

Oh...and time to explain the bullet...start by inserting center NAS pivot bolt..Its big and expensive 7/16 I think.Go to friendly aircraft bolt supplier and obtain a couple of AN 4 (5/8 I think).Hacksaw the head off and spend the day grinding down to 50 cal shape.You could use a hammer but mooney nose wheel steering linkage is pretty delicate.I used a 20 dollar 8in c clamp and with the bullet well greased up slipped in faster than Lindsley Lohan saying "not guilty your honor"!Well thats it..a job any competant Msc could do in 1hr per gear took...3 days!!kpc

[5854Q]

troy,  how did it go?

[sleepingsquirrel]

Hey, If he's like me he's still looking for all those quarters that fell out of the spring coils.

[5854Q]

Well.... I was hoping he would be done & have taxied away so that I could go looking for any wayward quarters..

[troy520]

Thanks again for all the great advice!  All went well.  The hydraulic tool worked great!  Found corrosion on the disc links that necessitated replacement, but no other surprises.  

[thinwing]

You are now a member of the exclusive Mooney biscuit club and entitled to wear old biscuits arround your neck.I have found many uses for old biscuits...1 sharpen the aluminum edges for combat hocky 2spray paint them gold and present to wife/S O as xmas ornament 3reusable skeet targets (the shot bounces right off and scares the bejeebers out of your shooting competitors) 4water wasting toilet floats 5sell them on ebay..you get the idea..kpc