Nose Gear Door Linkage Replacement

[Samir13k]

Hello all, my CFI recently recommended we ground my 1968 M20G until we can get the nose gear door linkages replaced. I have been waiting a week for the FBO mechanic to get me a quote, but I’d like to get the parts on order as it’s going to be weeks before he can get to it from the sounds of it.

The part is shown in the attached image, I’d need them for both nose gear doors as both are sloppy. It seems to me that the slop is all in the ball joints, but they’re recommending the whole assembly get replaced on both doors

Can anyone assist with the part numbers?1968 M20G. Thank you in advance!

[hammdo]

Heim ends should be all you need to replace. Make note of spacers and washers on the rod ends!

top heim is F34-14, bottom is F34-14N in the parts book. Very likely right and left had threads..

item 29 and 32 in pics

-Don

 

[EricJ]

The assembly is just an assortment of spherical rod ends and the threaded shaft that connects them and a few jam nuts.   Unless the shafts are horribly bent or the threads stripped completely off (both are unlikely), the shafts can be reused and just replace the rod ends.   The rod ends are not uncommon and can usually be sourced from a few different places.   I'd only replace the rod ends that actually have play.   It'd be unusual for all of them to have play, but if they do, they're not hard to replace.

 

[Samir13k]

Thank you both. I’ll see if I can have my CFI ferry it elsewhere and have just the Hiem rod ends replaced

Thanks again!

Edited January 21, 2025 by Samir13k
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[Ragsf15e]

Just now, Samir13k said:

Thank you both. I’ll see if I can have my CFI ferry it elsewhere and have just the HEIM rod ends replaced

Thanks again!

This is the easiest fix ever.  Even if you’re not too mechanically inclined, order the heim joints, install them and have your mechanic take a look and sign it off when you’re done.  Advise him first and see if he agrees.  If not, find any other A&P to just look at your work and sign.  Im not that great a mechanic, but I disconnect those parts (not tge ball joint part though) each annual to free the gear doors so I can access the inspection panel screws close to them. Don’t lose the tiny spacers in there!

[Samir13k]

1 minute ago, Ragsf15e said:

This is the easiest fix ever.  Even if you’re not too mechanically inclined, order the heim joints, install them and have your mechanic take a look and sign it off when you’re done.  Advise him first and see if he agrees.  If not, find any other A&P to just look at your work and sign.  Im not that great a mechanic, but I disconnect those parts (not tge ball joint part though) each annual to free the gear doors so I can access the inspection panel screws close to them. Don’t lose the tiny spacers in there!

Unfortunately I really doubt the A&P here will sign off on anything not done by them. Feels like a cash grab (but it could be for liability which I also understand). He already told me that he would have to put it up on jacks and swing the gear to check the door closure as well if they were to do the work, so I don’t think I’m getting a quick sign off.

They’re doing a full engine swap on an M20K that bit the dust here, and all 3 of the FBO’s planes are down for maintenance, so I’m pretty low on the totem pole of profitability and priority with this job for them

[Skyland]

The piano hinge fingers appears to have significant wear.  When the doors are are wiggled the door hinge half will move fore and aft and it might be interpreted as bad rod ends.  The slop in the hinge is not that big a deal but if you want to replace the piano hinge it's a standard part and not all that difficult to replace but requires match riveting onto the doors.

[Fly Boomer]

1 hour ago, Samir13k said:

Can anyone assist with the part numbers?1968 M20G. Thank you in advance!

Not sure how familiar you are with the documentation.  Here is a brief summary of the process.  Apologies if you already know all this.

First, you must have the IPC for your airplane (Illustrated Parts Catalog).  Here is one for an M20G in the Downloads area of MooneySpace, but you will need to be sure it covers the correct year and serial number for your airplane.  Usually serial number is more important than year -- Mooney changed things more frequently than once per year.

https://mooneyspace.com/files/file/176-m20-series-parts-catalog-1968-1978-2pdf/

As an example of how to find a part, in the illustration on page 142 (PDF page 134) one of the rod ends is numbered "29".  In the list following the illustration, "29" is identified as p/n F34-14 which looks like an oem p/n and not a Mooney p/n.  If they gave an oem p/n, you can frequently track it down on the Internet.  That said, Mooney was not always precise with those oem part numbers, so some interpretation may be in order.  A search for F34-14 yields an ebay advert which appears to identify a cross-reference part number (possibly a different oem), and sometimes those numbers can lead to further searches.  The ebay advert calls it a "flap rod end bearing".  Something like a rod end bearing may have been used in several places in a Mooney (or any other airplane) so don't get hung up on the suggested use -- it's the part number we are trying to match.

In the end, sometimes you order what appears to be the right part but, when you get it, you find that it does not match the part on your airplane, and you start over.

Finally, I didn't spend very much time on these searches, so you will need to verify these links for yourself.

https://www.ebay.com/itm/256606874390?mkevt=1&mkcid=1&mkrid=711-53200-19255-0&campid=5338678874&toolid=20006&_xiid=256606874390%26customid%3Ds%253AGS%253Bgc%253Abe1913013cdd12343de9748fcf09209f%253Bpt%253A1%253Bchoc%253A1&customid=s%3AGS%3Bgc%3Abe1913013cdd12343de9748fcf09209f%3Bpt%3A1%3Bchoc%3A2&msclkid=be1913013cdd12343de9748fcf09209f

https://store.vansaircraft.com/mw-3m-rod-end-bearing-bearing-mw-3m.html

https://www.aircraftspruce.com/catalog/appages/aurorabrng.php
 

[PT20J]

You should definitely swing the gear afterwards. I don’t see why some play in these rod ends should make the airplane unairworthy (which would be the only reason to “ground”it) but if your CFI really believes that he should refuse to fly it without obtaining a ferry permit. I would either obtain the parts and have your local A&P install them and swing the gear, or I would fly it to another shop. No need to get your CFI involved (and pay his fee) assuming you are current in the airplane. 

A lot of mechanics will not sign off the work of owners unless they know the mechanical abilities of the owner. It takes time to build up that level of trust. 

[Samir13k]

Unfortunately I’m a student pilot and Midwest winter weather means that I’ve gotten 10 flights in out of a scheduled 30-40 so far. My CFI says he’ll fly it somewhere nearby with the gear down if I want to go to another shop since he knows the FBO will take forever (he works for their flight school, so he knows how behind they are since all his flight school planes are down for maintenance with them).
 

I’m fine paying them for the work that does actually need to get done, but it sounds like myself and everyone is in agreement that just the hiem bearings need to be swapped and not the entire assembly. The shop says they cost $750 each and need to be fully swapped. In 1.5 weeks since they looked at it, they haven’t given me a quote or part numbers to order so I had been sitting here twiddling my thumbs wondering what to do next. Thanks to everyone for the guidance

[Samir13k]

2 hours ago, Fly Boomer said:

Not sure how familiar you are with the documentation.  Here is a brief summary of the process.  Apologies if you already know all this.

First, you must have the IPC for your airplane (Illustrated Parts Catalog).  Here is one for an M20G in the Downloads area of MooneySpace, but you will need to be sure it covers the correct year and serial number for your airplane.  Usually serial number is more important than year -- Mooney changed things more frequently than once per year.

https://mooneyspace.com/files/file/176-m20-series-parts-catalog-1968-1978-2pdf/

As an example of how to find a part, in the illustration on page 142 (PDF page 134) one of the rod ends is numbered "29".  In the list following the illustration, "29" is identified as p/n F34-14 which looks like an oem p/n and not a Mooney p/n.  If they gave an oem p/n, you can frequently track it down on the Internet.  That said, Mooney was not always precise with those oem part numbers, so some interpretation may be in order.  A search for F34-14 yields an ebay advert which appears to identify a cross-reference part number (possibly a different oem), and sometimes those numbers can lead to further searches.  The ebay advert calls it a "flap rod end bearing".  Something like a rod end bearing may have been used in several places in a Mooney (or any other airplane) so don't get hung up on the suggested use -- it's the part number we are trying to match.

In the end, sometimes you order what appears to be the right part but, when you get it, you find that it does not match the part on your airplane, and you start over.

Finally, I didn't spend very much time on these searches, so you will need to verify these links for yourself.

https://www.ebay.com/itm/256606874390?mkevt=1&mkcid=1&mkrid=711-53200-19255-0&campid=5338678874&toolid=20006&_xiid=256606874390%26customid%3Ds%253AGS%253Bgc%253Abe1913013cdd12343de9748fcf09209f%253Bpt%253A1%253Bchoc%253A1&customid=s%3AGS%3Bgc%3Abe1913013cdd12343de9748fcf09209f%3Bpt%3A1%3Bchoc%3A2&msclkid=be1913013cdd12343de9748fcf09209f

https://store.vansaircraft.com/mw-3m-rod-end-bearing-bearing-mw-3m.html

https://www.aircraftspruce.com/catalog/appages/aurorabrng.php
 

Just wanted to say thank you for the detailed response. I had actually looked this up in the parts catalog, but was confused by the need for the whole assembly as opposed to just the bearings/rod ends. I saw that both were offered but couldn’t quite narrow down what I was looking for as the G is not very popular and the lasar site was not very helpful. Really appreciate you taking the time to spell things out 

[1967 427]

2 hours ago, Ragsf15e said:

This is the easiest fix ever.  Even if you’re not too mechanically inclined, order the heim joints, install them and have your mechanic take a look and sign it off when you’re done.  Advise him first and see if he agrees.  If not, find any other A&P to just look at your work and sign.  Im not that great a mechanic, but I disconnect those parts (not tge ball joint part though) each annual to free the gear doors so I can access the inspection panel screws close to them. Don’t lose the tiny spacers in there!

I don’t have a good image of mine, but I have a spaces in front of and behind the ball joint on the door side.  Looking at the image it looks as if the front bracket is bent and you have 2 washers as spacers on the rear and on the front the 2 washers are not being used as spacers as they are not between the bracket and ball joint.  With the spacers installed there is no play between the door and the lower ball joint.  This alone could be the main source of slop. (My spacers look like 4 small pieces of tubing, 2 in front and 2 behind, they are small, each is about 3/16 in length) small trick, I would always have to search for one when I would disassemble, I installed heat shrink tubing around the 2 pairs.  Now it goes together with ease, and if I drop one of the spacer packs the blue heat shrink stand out on the ground.

[EricJ]

2 hours ago, Skyland said:

The piano hinge fingers appears to have significant wear.  When the doors are are wiggled the door hinge half will move fore and aft and it might be interpreted as bad rod ends.  The slop in the hinge is not that big a deal but if you want to replace the piano hinge it's a standard part and not all that difficult to replace but requires match riveting onto the doors.

+1 that the hinge should be checked as well just to make sure that the right part is being replaced.   A little slop in the doors may come from either the hinge or the rod ends.

 

[Samir13k]

Just now, EricJ said:

+1 that the hinge should be checked as well just to make sure that the right part is being replaced.   A little slop in the doors may come from either the hinge or the rod ends.

 

The slop is MOSTLY from the rod ends. All 4 have pretty bad wear in my opinion. There is some slop in the hinges too without a doubt, but I’d say it’s 85% rod ends, 15% hinges. Transparently there was a bolt and nut that held one of the linkage brackets to the door that was loose, and that caused the door to have a lot of play, that’s been rectified, but it brought the attention to the rod ends. I think once the rod ends come in (got them ordered) I’ll have them installed by an A&P and get their opinion.
 

Another operator at our base is supposed to open a shop in the next month that has a Mooney expert as their lead mechanic, so I’m counting down the days until that happens

[Fly Boomer]

11 hours ago, Samir13k said:

The shop says they cost $750 each and need to be fully swapped.

This sounds like a lazy mechanic who needs to make a boat payment.  The rod end should be around $20, plus an hour or two labor.  If a conversation with the mechanic doesn't resolve this discrepancy, then you need a different mechanic.

[Slick Nick]

I just had all 4 rod ends swapped on my J. Order them new from LASAR. My shop took about an hour to install them, then another half hour to swing the gear and adjust them so the doors closed up nice and tight.

Your CFI sounds a little, um... as though they need some coaching in the nuances of pilot decision making. The gear works fine, the doors close normally, why risk something like an engine failure after takeoff with gear that's stuck down? And why the ferry permit? Ferry permits are only applicable to aircraft with an unairworthy component. It's airworthy, and even if your CFI made the decision to fly it gear down (again, why?) you don't need a ferry permit to fly a retractable with the gear down. This, to me, is sounding some alarm bells about this CFI. Maybe you should be looking for another one.

If the rods haven't yet been adjusted, there is no harm in retracting the gear like normal. Fly it to a shop who knows what they're doing, and have them changed in an afternoon.

[Slick Nick]

32 minutes ago, Fly Boomer said:

This sounds like a lazy mechanic who needs to make a boat payment.  The rod end should be around $20, plus an hour or two labor.  If a conversation with the mechanic doesn't resolve this discrepancy, then you need a different mechanic.

Agree. Samir, get your airplane out of there and take it to a shop who is wiling to work with you. It's nowhere near as complicated as they're making it seem.

[Slick Nick]

10 hours ago, EricJ said:

+1 that the hinge should be checked as well just to make sure that the right part is being replaced.   A little slop in the doors may come from either the hinge or the rod ends.

 

Fore-aft slop in the piano hinge can sometimes be cured with a little bit of safety wire in one or more of the gaps. Gets rid of the slop.

[cliffy]

Lets step back a take another look here-

The upper piano hinge could use one wrap of safety wire around the center wire to take up the fore/aft slop

Easy fix -

Next - Wear in the ball joints takes 2 forms- one is wear in the ball itself moving radially in its housing and 

the other wear point is the fit between the ball hole and the bolt that goes through it. Both are easy to check.

If the bolt is loose in the ball it might only be wear on the bolt. Try a new bolt in the hole to see if the wear is less,

if not its a new rod end you need. IF the wear is in the ball in its holding socket (again easy to check) the its a new 

rod end also.

What it looks like to me from your picture is the mounting of the bolt through the ears and ball end, It looks as if the sleeve bushings

that go between the door ears and the ball on either side of the ball are not there letting the rod end slide back and forth on the bolt.

Further evidence is the view seems to show then one ear bent back toward the rod end and not perpendicular to the door side. 

I can't see anything more here than finding the correct size bushings (ID 3/16ths and length to match what's needed), straightening the bent door ear and a short gear swing to verify that the doors work correctly. 

YOU WILL NEED A GEAR SWING

I'm willing to bet that the ball ends ends are OK, might need new cross bolts and definitely fix the missing bushings, 

(ref to 1967 427 post above)

NOW for the kicker-  $750  for each end? RUN- DON'T WALK -AWAY FROM THAT SHOP! PERIOD!

That is a total rip off. You need to find another shop NOW and never go back there. JMO but I've been

an A&P for 60 years!

Find another shop, get with your CFI and fly it there. Talk to them about what you need BEFORE you go there and what they want to do to fix it. Show them this thread by email so they have an idea of what you need. 

This is a simple a low cost fix for an airplane. Not the usual high $$$$$ maintenance issues we see here often. 

BTW any HEIM joint that has a Mil Spec number attached to the paperwork is a legal part to use. It doesn't have to be 

a Mooney part.  With a little looking you can find the correct size HEIM joint with a Mil Spec #  Maybe AC Spruce. 

[Yetti]

This is the short version of what Cliffy wrote.  Your mechanic does not know what they are doing and is scamming you.   There are some washers that have ridges on them if you have the original washers.   They go against the hemi ball.   The washer with ridges are actually little bushings that go into the ball.     It looks like one on the lower left may be installed on the outside of the door tang.   Even so to get the doors to work best, the right number of washers need to be installed between the joint and the two door tangs.  Your picture shows two washers on the outside of the tang and that is wrong.   that looks like a nose door.  The drawing posted above is for the main gear.  Find the parts manual and look up the drawing.

[PT20J]

I don’t know about washers with ridges, but the “sleeve bushings” @cliffy refers to are spacer p/n 550017-005 listed in item 12 of the IPC page posted above. The IPC drawings are representational and do not always include small parts. There are 4 spacers: one goes on each side of the rod end on each gear door.

[hammdo]

Those -005s are like hen’s teeth to find… may have to call MSCs to see if they have them…

-Don

[EricJ]

28 minutes ago, hammdo said:

Those -005s are like hen’s teeth to find… may have to call MSCs to see if they have them…

-Don

I think over time they often just get replaced with washers.   That's how mine is.

So, essentially, in the pic at least one washer could be between the ball and the bracket to provide better spacing.

[Samir13k]

Thanks for the help all, its getting flown to another location on Monday and I'll have them give their opinion, but I'm providing the Heim bearings and theyre going to install them and swing the gear to get the door closure setup properly. I'll have them look at the hinges as well. I was able to find the heim bearings on ebay as they were available right away, but Lasar did have them as well (as well as the 550017-005). 

To clarify, I did use the term "ferry" more loosely than I should have, but the CFI does insist on flying it there with the gear down. Its going to a shop he recomended, so I'll see what they have to say. I appreciate the help of everyone here to get me flying again, and also save me $1000-2000. My CFI is fairly young, but he has 1600 hours and as the student I'm going to let him do what he thinks is proper (as long as its not costing me an arm and a leg when it doesnt need to).

In regards to the existing Heim bearings, the wear is on all four bearings and its the ball being loose in the sockets. My Statesman is mostly original, and the last pilot that owned it was a bit of a cowboy in the fact that he'd just get in and go as opposed to giving it thorough inspections. I'm learning as well so this has been very helpful. I most definitely dont think the bushings are there based on my memory of seeing it so I'm ordering new bushings as well (550017-005)

[PT20J]

All the rod ends (aka Heim bearings) should be lubricated with a shot of Tri-Flow every so often.