struggle to get gear locked down on '68 M20C

[DXB]

I'm doing transition training in my new to me '68 C and have a gear issue.  A reputable MSC mechanic in GA who is also an experienced pilot and CFI did the pre-buy on it. He subsequently did work on the gear that included replacing all biscuits, which were '68 original, as well as changing a corroded nose gear spindle and bearings.  Afterwards he operated the gear on jacks and also flew it himself - apparently the gear worked fine. 

 

I've flown it twice now while getting instruction from a senior Mooney instructor and former C model owner.  I have no issue pulling the gear up- surprisingly easy.  But I try to put the gear down at 100-120mph and have a miserable time.  Most of the movement toward the locking block is easy and smooth, but securing it is a nightmare.  This requires hard forward pressure with both hands for the last few millimeters to allow the sleeve to slide up and engage the pin.  I spoke to the MSC mechanic and read up on technique again to make sure I'm doing things right, then went back and tried again. Still no luck.  It feels as if something is preventing the last few millimeters of forward travel.  I do notice that when locked up the bar contacts the plastic center console containing the flap and trim position indicators.  But the console doesn't seem loose or incorrectly positioned so I'm not sure this is the problem.    

 

I spoke to the mechanics on my field who seemed to have little experience with the Johnson bar system and couldn't get it into look for at least a week anyway. I'm wondering if there's any guidance I can give them, or if i should just get it ferried to the nearest MSC in Robbinsville.  Or lastly, is the problem just my own inexperience?  This is what I thought after my initial flight, but now I'm doubtful.

 

[xrs135]

I'd say you need to get it looked at one way or another. When I got my 68C I had ZERO experience with the J-Bar, and I've never had an issue unlatching or latching the gear handle. It should be an almost effortless process, certainly not requiring pressure from both hands.

[N601RX]

120 mph is to fast, but that has the most affect at about 1/2 up. If it's only the last 1/4 inch or so it is most likely rigged with to much preload. You need to find someone who has the preload plates and knows how to use them. Don't let anyone adjust it who doesn't have them.

[Danb]

Go to Henry Webers in Lancaster. Dorn has a reconditioned . C there a MSC may be easier and closer to you most likely similar distance

[Hector]

I would suspect there is a rigging issue. I would hope that after your mechanic did all that work on your gear he checked the rigging before signing it off. If he did not, I would suspect highly that your preload is very high. With a properly rigged gear you should have no trouble at all lowering the gear even at 120 mph.

[orionflt]

120 mph is to fast, but that has the most affect at about 1/2 up. If it's only the last 1/4 inch or so it is most likely rigged with to much preload. You need to find someone who has the preload plates and knows how to use them. Don't let anyone adjust it who doesn't have them.

120 is not too fast, in fact that is the speed i use all the time in my C. as for what you said about only letting someone who knows how to rig a mooney should touch it.

Dev,

where are you based? I am in Quakertown. from what you are describing it sounds to me more like something fell down in the hole for the Johnson bar and is adding resistance when you put the gear down. there is a possibility the rigging has an issue but if you have that much of an issue getting it locked down the mechanic that did the work would have noticed the issue. the best thing to do is put it up on jacks and take a look. PM me and we can see about getting things fixed for you.

Brian

[carusoam]

Welcome aboard Dev,

Weber and Air Mods are our local MSCs.

Could be part of the transition training...

The gear does take some getting used to. One speed works well for putting it up. Another for putting it down.

Using two hands is typical of not having the right speed.

Unfortunately, you have described what I went through my first month or so with a C.

What you see at the top of the hole is a switch for lighting the down and locked light...it also keeps the gear horn quiet in a deep descent.

What can you do...

(1) ask your local mechanic for guidance. Worst thing he does is tell you it needs to be jacked up for inspection... Then you get good practice while it is on the ground.

(2) if you need real MSC level help you can call the MSC. They can come and pick up the plane. This starts getting expensive if the problem isn't really a physical problem...

Like you are doing here... It is better to ask, than to experiment...

Did anyone mention the NJ Mooney Pilots web site to you?

Best regards,

-a-

[47U]

My gear was smooth as butter. First annual I discovered my gear over-center tensions were all low. I adjusted the torque to spec and the handle was a bear to lock down with the gear doors hanging down 3/4" from flush with the bottom of the wing. I started looking for slop in the linkage and bought $.3 AMU handfull of bushings and bolts from LASAR. That fixed it. If your gear doughnuts were original from '68, maybe you're also due for some new hardware in the gear linkage.

[N201MKTurbo]

Is your boot binding? I've heard that some people have made custom boots that would bind up at had end of the throw.

[cliffy]

Carpet or padding on the nose gear tunnel or your J bar boot at the bottom could he bunching up From there you might have too tight uploads. I'm going to presume that the gear has been properly lubed.

You might also look at the big springs in the wings. I had one with popped rivits on my prebuy years ago on my C.

Do not check over center preload without the proper tools, period.

[Glenn]

Is your boot binding? I've heard that some people have made custom boots that would bind up at had end of the throw.

I experienced this very thing when I put a new vinyl boot on the Johnson bar.  Check that you do not have too much material forward of the bar when the gear is extended.

[DXB]

Great knowledge on here, thanks for help all around.   Spoke again with my original MSC mechanic in GA (Joe Cole- good guy BTW in case anyone was thinking of using his shop).   Joe said he would be surprised if a rigging/preload issue came up so soon after he worked on it.  He suspected something having shifted or fallen down against the bar to impair the last bit of forward motion, as some folks suggest above.  If so, it may be an easy fix from the shop on my field- it' a bit of a pain that I can't fly it myself to someone with more expertise currently.  If rigging is an issue, Joe offered to talk to the guys and walk them through any related work by phone. This still makes me a tad nervous, and maybe I'll have to see about arranging a ferry flight at that point.   More to come...

[carusoam]

Fortunately, the gear is in the down and locked position. It can be left that way for ferry purposes...

Remember to observe normal gear speeds if you decide to move it.

There is another issue that happens with old up-lock blocks... They wear into an oval egg-shaped pattern. Easy to have replaced.

If you are going to the MSC, talk to Dave or Dorn (depending on the one you choose) before going. Review your situation...

Joey Cole is a well respected resource.

Thoughts of a PP, not a mechanic...

(1) Check with you local mechanic. Put the plane up on jacks. Review the operation of the gear. Determine if anything has gotten in the way. Look at rug, boot and aluminum lock blocks...

Remember the forces while on jacks will not be representative of the forces while flying.

(2) the MSC has the equipment and know-how to set up the gear to specifications.

(3) after that, airspeed, bank angle, and momentum make things pretty easy for the system when it is set up properly.

Remember the forces of the J-bar are really high if it gets released during cruise flight. Something to be avoided...

Expect to swap out the lock blocks if they are 50 years old.

The manual landing gear is challenging to goof up. Use your superior logic skills. We have one pilot that has collapsed his landing gear, twice? Lesson learned make sure it is down and LOCKED (completely).

Best regards,

-a-

[gsxrpilot]

I understand that my C had the same problem, pre my purchase. The previous owners solution was to remove the boot around the J-bar. While it was in Don Maxwell's shop for the PPI, he noted the missing front part of the boot as an airworthy issue. (A pen or something could fall down under the floor and jam a linkage.) After the purchase, Don PROPERLY installed a new boot and the gear is up and down like butter.

[Rhumbline]

I had a very similar problem about a year ago after having had all of the shock discs replaced and the nose wheel truss overhauled and updated on my '68.  The mechanic conducting the work indicated that the gear handle seemed to him difficult to secure but assured me that everything was properly rigged.  Since the plane was already off of the jacks, he asked me to let him know if the effort to secure the gear was inordinate after flying it.  It certainly was.  I could not secure the gear in the retracted position and it took both hands and much force to secure it in the extended position.  I reported this to the mechanic and, certain that everything else had been correctly rigged and double checked, he surmised that old congealed grease in the handle combined with cold temperatures was the culprit.  I rolled my eyes to myself.  He later jacked the plane back up, put some direct heat on the gear handle and, sure enough, the Johnson bar worked as smoothly as a Johnson bar can work.  I was gob-smacked!  The old lube was cleaned out and the handle re-lubricated and it has worked flawlessly ever since (approx. 100 hrs & 150 cycles).

 

I didn't do any trouble shooting during the flight I made due to the trouble I had with the single cycle of the gear and I landed as soon as it was securely extended.  It felt to me as though it were both difficult to push the bar into alignment with the blocks and to slide the handle into the block.  I realized after the fact that the relatively small amount of resistance required to align the handle with the blocks combined with the abnormal force required to slide the handle into the block gave a perception that more was going wrong than actually was.  Hope this helps!  

[furledd]

One quick thing you can do if its not the boot interfering and the preload is correct and grease is good,  is to disconnect each wheel from  the linkages.

 

Then see if you can smoothly move the mains and nose gears up and down their range easily by hand.

 

I had a lot of effort to raise mine the last inch or so on the J bar, and it turned out that the steering horn was shimmed so tight that it was binding a LOT at the top of the range for the nose gear. Once a shim was removed on the end of the steering horn, the nose gear moved way easier, and the effort in the J bar dropped dramatically. 

 

We all have our own stories eh?

[N201MKTurbo]

The Johnson bar is a wonderful thing. If you have an actuator it will dutifully raise and lower a binding gear system while wearing itself out prematurely. The Johnson bar will instantly tell you when something is wrong.

[1964-M20E]

I had a similar experience with my 64 E models not too long after I bought it seemed like it happened overnight.  I got under and lubed up all the bungees and preloads the problem went away especially on the main gear linkage inside the wheel well where the spring is.

 

Get it on jack stands and with help slowly actuate the gear and watch all the moving parts see if anything is binding. Grease and lube all moving parts then try again.

[Alan Fox]

I crushed a smartphone in the bar once , It would not lock in , when it did and I landed and saw it I felt like an idiot....

[N201MKTurbo]

Those springs should be lubed at every annual.

[1964-M20E]

Yeah you are right.  I was looking at a plane once that had an annual just a month prior and kept in a hangar all pivots and rod ends were as dry as could be.  So much for lubing at annual.  No I did not buy that one due to many issues.

[DXB]

Ok I'm feeling like a buffoon now. I got the plane to my nearest Mooney shop (AirMods) yesterday.  Everyone in the shop, including owner Dave, worked the gear on jacks today and agreed it felt just fine: "one of the easier ones we've seen". Feeling incredulous, I drove up and worked it myself, and well...I agree it works fine. If I am slow in pushing the bar forward for the last bit of travel toward the block, it is harder to lock it down, but not nearly as hard as I had found in the air, where I have to push hard with both hands on the bar to get it forward to slide the sleeve up.  Dave will fly it tomorrow and we will learn if this is really true.  It is entirely possible that it is just my own Johnson Bar newbie incompetence (I suspected initially but then managed to convince myself otherwise).

 

At least I'm getting a couple of other annoying squawks fixed by them and my baffling tightened up.

[carusoam]

Dave and his office mate are some incredibly helpful people.

Learn as much as you can while you are there...

Best regards,

-a-

[Marauder]

Ok I'm feeling like a buffoon now. I got the plane to my nearest Mooney shop (AirMods) yesterday. Everyone in the shop, including owner Dave, worked the gear on jacks today and agreed it felt just fine: "one of the easier ones we've seen". Feeling incredulous, I drove up and worked it myself, and well...I agree it works fine. If I am slow in pushing the bar forward for the last bit of travel toward the block, it is harder to lock it down, but not nearly as hard as I had found in the air, where I have to push hard with both hands on the bar to get it forward to slide the sleeve up. Dave will fly it tomorrow and we will learn if this is really true. It is entirely possible that it is just my own Johnson Bar newbie incompetence (I suspected initially but then managed to convince myself otherwise).

At least I'm getting a couple of other annoying squawks fixed by them and my baffling tightened up.

What speed are you trying to get the gear down at? Wonder if are dealing with wind resistance.

[DXB]

What speed are you trying to get the gear down at? Wonder if are dealing with wind resistance.

Have worked it in the 100 to just under 120 range.  Wind makes sense conceptually to me, but POH says easier at higher speeds under Vlo.