Gear overhaul on E model

[deanders]

I'm in the process of  overhauling the gear on my 1965 E model. I removed all three gear and bead pasted for inspection. After 50 years of use I thought I should inspect it for ware. The disc were dated 1965 and several zerk fittings would not take grease. Once removed and inspected I found the nose strut was worn and needed to be replaced along with one main gear shock link, bushings and knee bolts. I'm also replacing the Johnson down lock block due to ware. After power coating it will be reassembled using all new hardware and shock disc.

Has anyone replaced the steering horn assay with Lasar rebuilt assy? If so was there a marked improvement?

This is the last piece of a two year process of restoring the old bird. For those interested, the cost for the gear will be about 5 grand not including labor to remove, reinstall and rig.

[KSMooniac]

The LASAR unit will have the turn stops added, so little chance of line service bending tubes.

Sent from my VS985 4G using Tapatalk

[deanders]

thanks

[lamont337]

What was worn on the nose strut exactly? This info could help other Mooneyspacers.

And was there no overhaul option?

[Sabremech]

How much wear does your main gear have on the forward and aft bearing surfaces? I had to replace my right gear leg because I had more than 20% wear of the tube thickness at the rear bearing surface. My airplane has close to 7700 hours on it with who knows how many landings. 

David

[Bob_Belville]

I'm waiting for two "walking beams" to be fabricated for my '66E. On the right main one side of the "fork" was broken off. On the left main one side was cracked. Lynn told me DMax has a sizable collection of broken Walking Beams. I think the part has been revised.

My plane has the LASAR wheel well liner which has to be removed to see this part.

[BKlott]

My Dad had his C model's gear rebushed in 1970 and I can still remember him complaining about the cost back then.

[Vance Harral]

11 hours ago, deanders said:

Has anyone replaced the steering horn assay with Lasar rebuilt assy? If so was there a marked improvement?

We got a new steering horn assembly from LASAR 2.5 years ago, which, along with new rod ends, eliminated an ongoing nosewheel shimmy problem.  This was the "final" repair after first trying checking nosewheel tire pressures, then checking nosewheel alignment per Service Bulletin M20-202, and even installing a new LASAR bushing.  Only the new steering horn and rod ends solved the problem.  Haven't had an issue since, in hundreds of takeoffs and landings.

Note that LASAR actually sells three different steering horn assemblies.  I call them the "factory early" model, the "factory late" model, and the "LASAR PMA" model.

You can see the factory early/late model steering horns in this photo: http://www.lasar.com/mod-details.asp?id=30.  The late model is the beefier one on the bottom.  I'm not sure what year Mooney switched from the early to late model, but our 1976 M20F already had a late-model steering horn, which we replaced with the same part.  Older models can be upgraded to the late-model horn, but it requires modification of the tubular structure in the nose wheel to which the horn attaches.  My understanding is it involves grinding/welding/drilling.

LASAR also advertises a PMA-approved replacement horn, which you can see here: http://www.lasar.com/mod-details.asp?id=20.  At the time we were buying, LASAR steered us away from that one.  It wasn't clear to me if they were having problems with it or just didn't have any in stock.

[Vance Harral]

On a related note, I'm seeking advice about inspecting/cleaning/painting our main gear trusses.  As shown in the attached photo, they're filthy, and the paint on them has significant cracks. The dirt and cracks in the paint could easily disguise cracks in the trusses themselves, which concerns me.  I've asked a couple of different mechanics about it and all they do is probe a few spots with a dental pick, sign it off, and tell me it's extremely unlikely to be a problem.

The no-apologies fix would be a full rebuild and powder coat as deanders is doing, but that's arguably excessive for a '76 model with only 2800 hours that's almost always been hangared.  I also found this site, which suggests the trusses can be sanded, cleaned, and repainted in-situ: http://www.mooneyland.com/say-no-to-ugly-legs/

At our upcoming annual, I figure at bare minimum I'd like to really clean the wheel wells and trusses with a solvent and/or pressure wash, but not sure if that might have adverse affects.  I've had it suggested by knowledgeable mechanics there's such a thing as "too clean" for moving parts exposed to dirt and dust - that the film of oil and grease actually helps keep grit out of spaces where it can do damage.  All I really know about the trusses at this point is they look ugly.  Would like to hear what others do in the way of care, maintenance, and inspection.

 

[Bartman]

Like Vance and many others have done before we removed the nose gear and sent it to LASAR for rebuild last year. Can't remember everything, but they replaced the discs, upgraded to larger size bushings and larger size bolt, and and steering limits too. We also replaced the steering horn and I know it was worn out because I felt the wear when we had her on jacks, and I was shocked to find out how much play there was!!! Prior to that I had intermittent chattering vibration in the pedals on landing and have not seen anything like that since then. This year we tackle the trim jack screw, trim motor, and trim limit, and indicator.

I am very pleased with the quality, the price, and the result from the LASAR nose gear rebuild.  

[deanders]

The nose strut was worn where it pivots in the trunnion, lower flange. The bushing has worn half way through the metal, also the tubing was dented due to ground handling. Lazar offers an overhaul exchange for this. The tube thickness in the main gear trunnion are in tolerance along with the blocks they slide into. The top surface of the right walking beam showed a little corrosion pitting on the top surface but within tolerance. Total time on this aircraft is 4500 hours

As far as cleaning the gear in place, in my opinion pressuring washing would be ok as long as you grease and lube all areas and preform gear retraction checks before you fly. One reason I pulled the gear is because I had 3 or 4 zerk fitting that wouldn't take grease. Several of these the bolt had rusted to the bushing so I needed to heat the bolt using oxy/acc torch in order to remove it.

I had my aircraft painted a year ago and the paint shop did a nice job of cleaning the exposed areas and painting the gear. It looks ok from a distance. They did remove the main gear doors for this.  

Thanks for the feedback, I'll keep you posted as I work through this.

[Vance Harral]

30 minutes ago, deanders said:

I had my aircraft painted a year ago and the paint shop did a nice job of cleaning the exposed areas and painting the gear.

I've always wondered about this.  If I understand you correctly, the paint shop didn't remove the trusses, but rather painted them in place?  Did they strip the old paint off first, or just "scuff and shoot"?  Seems like it would be difficult to paint the gear in-situ, without getting paint into all the moving parts.

[deanders]

They cleaned, scuffed and shoot. It's not the ideal way to go but I had planned to remove the gear anyway. As far as the "moving parts" it didn't seem to be a problem with the gear operation. The key is after cleaning/paint, lube, lube swing the gear and check rigging and down lock tensions 

[deanders]

As you can see on the pics I have posted, the gear after painting was poor where they couldn't get to. It's expensive to remove, inspect, powder coat and reinstall but, once this is done your gear shouldn't need any other service other than yearly maintenance. Not to mention, It will look like new. For the cost of an avionics upgrade your gear looks good and shouldn't collapse on you.

[XXX]

At my PPI my mechanic recommended that the main gear be removed, stripped and inspected since he couldn't get a good look at the gear due to accumulated coats of paint over the years. The plane was almost due for annual so before I ever flew her, we went ahead and removed the main gear, stripped and powder coated. I stripped the wheel wells and had them alodyned and new brake hoses installed as well. The difference visually is remarkable. 

[Vance Harral]

That looks great, Chupacabra.  Can you and/or deanders share the approximate hours of labor involved (which I'm sure is the bulk of the cost, not the paint/alodyne)?  I know it's "a lot", but would like to get an approximate number to use as a basis for discussion with my airplane partners.

[deanders]

So far I have 16 hours it. That's removal, disassembly, bead blast and inspection. I'm estimating  to complete I'll total hours spent 40 to hours. Nice job Vance on your aircraft. 

[XXX]

40 minutes ago, Vance Harral said:

That looks great, Chupacabra.  Can you and/or deanders share the approximate hours of labor involved (which I'm sure is the bulk of the cost, not the paint/alodyne)?  I know it's "a lot", but would like to get an approximate number to use as a basis for discussion with my airplane partners.

Vance,

Thanks, I would have to look at my invoice to be sure. I did a lot of the stripping and grunt work myself. My neighbor does bead blasting and powder coating, so that cost was separate from the annual. I'll look up my invoice tonight and see how many hours my mechanic charged. 

[XXX]

5 hours ago, Vance Harral said:

That looks great, Chupacabra.  Can you and/or deanders share the approximate hours of labor involved (which I'm sure is the bulk of the cost, not the paint/alodyne)?  I know it's "a lot", but would like to get an approximate number to use as a basis for discussion with my airplane partners.

Vance,

My invoice shows 14 hours to R&R the main gear and 5 hours to fix leaks and replace brake hoses. I think I had about 8 hours in stripping the wheel wells. I gave my neighbor $300 for bead blasting and powder coating. 

Hey, by the way. Our serial numbers are just 25 apart!

Best, 

Steve

[Vance Harral]

Thanks for the great info, Steve (and danders).  The labor doesn't look too bad, especially with some owner-assist grunt work.  I like to do as much of that as possible, and I have a mechanic who's amicable to that.  But I also have a day job, so my DIY work typically has to be carved up into 2-3 hour chunks.  Makes it a little harder to commit to bigger jobs, just due to the total downtime if things stretch out.  That's actually our biggest barrier to a "no apologies" overhaul of the gear hardware.  As a partnership, we have a general obligation to try to minimize downtime, so everyone can fly.  Not that we skimp on maintenance, but the partnership results in a reasonable and appropriate amount of "if it ain't broke don't fix it" pressure.  We take a certain pride in the idea our airplane is a work (fun) horse, not a showpiece.

Congratulations on having chosen an airplane in the optimum serial number range.    We're pretty far across the country from each other, otherwise I'd suggest a 1976 M20F meet-up this year!  Maybe we still should - we have airplanes at our disposal, after all...

[deanders]

What down lock tensions are you guys using? My old service manual has 140 to 200 on the nose and 275 to 350 on the mains. Does that sound right.  I'm having a hell of a time getting the mains set. I'll have one side set at 325 and the other is at 225. I adjust the low one one half turn And they swap readings. I have the nose at 180 inch pounds. I can get them both set at 225 inch pounds but as I try to increase the tensions things go south. Help!

[RLCarter]

Way too high, Nose 100~130 in-lbs, mains 250~280 in-lbs. Service Bullettin M20-155 spells it out

[Hector]

What down lock tensions are you guys using? My old service manual has 140 to 200 on the nose and 275 to 350 on the mains. Does that sound right.  I'm having a hell of a time getting the mains set. I'll have one side set at 325 and the other is at 225. I adjust the low one one half turn And they swap readings. I have the nose at 180 inch pounds. I can get them both set at 225 inch pounds but as I try to increase the tensions things go south. Help!

 

For my C model it's 100-130 for the nose and 240-280 for the mains. That's inch-pounds and right and left main should be within +/-25 of each other

[deanders]

Thanks guys that helps a lot. 

[Andy95W]