M20J gear rigging

[RangerM20]

I had my J model jacked up, and the right main droops a bit.  The A&P says the gear will have to be re-rigged.  Is this true, or is there another way to fix this?

[Fritz1]

Depends on how much it droops, maybe gear door can be tightened to close better, go see the technician and have him explain

[RangerM20]

No, it's actually the gear itself, along with the door, of course.

[Pinecone]

If the gear is dropping, I would WANT the rigging to be checked.

[N201MKTurbo]

You should look at the overcenter link bushings. 
 

Undo the main gear door links so the door hangs down loose. With the gear up, push the wheel up and down and look at overcenter link. If it moves laterally, the bushings or bolts are warn. The slop here can make the gear hang down. 

[RangerM20]

Thanks, I'll check that.

[RangerM20]

Ok, it's worn.  So, we're replacing the link, bolts and bushings.  However, when we pull the NAS bolt(not the clevis bolt) out, it won't clear the airframe.  Is there a way to get this bolt out without dropping the whole main gear assembly?

[Ed de C.]

I can't advise you on the bolt removal, but I can commiserate.  I just went through a full gear rigging on my Ovation and it was 3 and a half days of hassle/frustration with my A/P.  We found both inboard gear door control horns severely bent to the point where they were contacting the spar.  Clearly some prior rigging episode jammed something to cause that level of deformation.  2 new horns on order for $1,500.  The leadtime is 8 weeks, so in the meantime the tech straightened the existing brackets (horns) to function.  We're OK with that since it's temporary and there's little load on that part of the horn actuating the inboard gear door.  As a mechanical engineer, I nodded sagely at my mechanic's proposal.  

After rectifying that, we had a problem with the nose gear door (pilot side) that would not close completely.  It seemed the nose wheel was retracted high enough, but the door link was too long and had no adjustability left to shorten.  The tech found that by playing with the washers around the rod end bearings he was able to get the door to close fully.  I don't like the fact that we are out of travel, but it seems to solve the problem for now.  

Other than these two problems, we found that by following the service manual to the letter we were able to get everything to work out.  Had it not worked out and we needed, say, more nose wheel up travel, it would have been a miserable process of playing with the nose gear eccentrics and the main gear adjustable spring compressions.  The manual is 90% but the missing 10% will tear your hair out.  Someone who does gear rigging all the time should offer a supplement.  My A/P said my gear was the most challenging he had experienced.  

Best,

Ed

[takair]

On 3/16/2024 at 4:01 PM, RangerM20 said:

Ok, it's worn.  So, we're replacing the link, bolts and bushings.  However, when we pull the NAS bolt(not the clevis bolt) out, it won't clear the airframe.  Is there a way to get this bolt out without dropping the whole main gear assembly?

It’s been a few years, but I recall having to pull the gear.