MLG Retract tube roll pins

[Marc_B]

Have the Mooney at annual and one of the items they noted was that the main landing gear push pull tube roll pins have slight fore-aft play.  Recommended replacing the tubes with estimate 14 wk lead and 1.5AMU.  Is this a common issue and is there an allowable tolerance in play?  I tried looking at Service Manual but couldn't find any specific info.  Has Mooney come out with a better tube (shop said something about welded vs roll pin connections) vs source from salvage?  Looks like PN: 560244-501 if I'm looking at Parts Catalog correctly. 

Partscatalog_MLG.pdf

[carusoam]

Just guessing..

The pins are steel, the tubes are aluminum… wear goes to the softer metal…

Haven’t seen this lately.

Mostly, because the tubes and roll pins don’t see any relative motion….

Don’t know if it is possible to have electrolysis going on… is that corrosion at the end of the tube as well?

 

Ask @M20Doc if the holes can be cleaned up and a new proper pin installed…. (Gear tube wear at roll pins)

It may just cost less to get new tubes…

Best regards,

-a-

[Guest]

I’ve seen play in these rod ends/tubes when someone has replaced the rod end, but done a poor job drilling the hole through the bearing.  The come un drilled from Mooney, the tube and bearing are steel.

 Before waiting 14 weeks for a replacement, I’d ask Mooney engineering for approval to up size the hole from 1/8” to 5/32” roll pins.

Clarence

[Marc_B]

1 hour ago, M20Doc said:

Before waiting 14 weeks for a replacement, I’d ask Mooney engineering for approval to up size the hole from 1/8” to 5/32” roll pins.

Clarence,

I'll have to sort back through the logs to see if the rod ends were ever listed as replaced...I don't recall that off the top of my head.  But I'll reach out to Mooney and see what they say.  That was my initial thought but the MSC I'm at said he thought that was a no go.

Marc.

[Marc_B]

1 hour ago, M20Doc said:

I’ve seen play in these rod ends/tubes when someone has replaced the rod end, but done a poor job drilling the hole through the bearing.

@M20Doc

Quick scan through logs...2010 removed left MLG retract tube assy, replaced rod end roll pins and re installed tube assy; 2012 replaced roll pins on RH MLG retraction tube fwd rod end with new P/N P19-125-0750-ZM.  Hmm.  Sounds like you called it.  Is this a common issues?  Normal wear and tear with use of gear or indicative of something else?

Thanks again!!

Marc.

[LANCECASPER]

39 minutes ago, Marc_B said:

@M20Doc

Quick scan through logs...2010 removed left MLG retract tube assy, replaced rod end roll pins and re installed tube assy; 2012 replaced roll pins on RH MLG retraction tube fwd rod end with new P/N P19-125-0750-ZM.  Hmm.  Sounds like you called it.  Is this a common issues?  Normal wear and tear with use of gear or indicative of something else?

Thanks again!!

Marc.

Maybe back then the bearings weren't getting lubed regularly.

[Guest]

10 hours ago, Marc_B said:

@M20Doc

Quick scan through logs...2010 removed left MLG retract tube assy, replaced rod end roll pins and re installed tube assy; 2012 replaced roll pins on RH MLG retraction tube fwd rod end with new P/N P19-125-0750-ZM.  Hmm.  Sounds like you called it.  Is this a common issues?  Normal wear and tear with use of gear or indicative of something else?

Thanks again!!

Marc.

Replacement of the rod ends happens.  Poor technique, wrong sized drill bits etc. can cause the issue you’ve got.

Clarence

[PT20J]

4 hours ago, M20Doc said:

Replacement of the rod ends happens.  Poor technique, wrong sized drill bits etc. can cause the issue you’ve got.

Clarence

Seems like it would be really difficult to drill two holes perfectly perpendicular so that the entry hole on one side of the tube perfectly matches the exit hole on the other side without some sort of jig. How do you do that?

Skip

[EricJ]

10 minutes ago, PT20J said:

Seems like it would be really difficult to drill two holes perfectly perpendicular so that the entry hole on one side of the tube perfectly matches the exit hole on the other side without some sort of jig. How do you do that?

Skip

A piece of paper or similar wrapped around the original makes a nice template for drilling one of the holes and making a pilot for the second.   With the rod end lined up with the first hole drill through to make the exit hole.   Use the pilot of the other hole to line that one up properly with the rod end in place and then similarly drill through to make the exit.

There are usually cheaty ways to do stuff like this.   There may be easier ways, too. 

[KB4]

On a press or new school, have talented MSer 3d print a 2” block, drill rod center hole, then on ends drill small pilot holes on top and bottom using old school connect the corners to find center.  Then step drill up to whatever Correct size. Once you have 2 pilot holes, drill up next size on one side, then push bit thru tube till you feel the bottom pilot hole centering the bit inside the tube, hold drill at 90 and away you go. 

[KB4]

16 hours ago, M20Doc said:

I’ve seen play in these rod ends/tubes when someone has replaced the rod end, but done a poor job drilling the hole through the bearing.  The come un drilled from Mooney, the tube and bearing are steel.

 Before waiting 14 weeks for a replacement, I’d ask Mooney engineering for approval to up size the hole from 1/8” to 5/32” roll pins.

Clarence

Walking Mooney encyclopedia Clarence is.  Diagnose correctly from pics!  Wow. And that has happened more than a few times. Lucky to have him and others here. Thanks guys. 

[Guest]

8 hours ago, PT20J said:

Seems like it would be really difficult to drill two holes perfectly perpendicular so that the entry hole on one side of the tube perfectly matches the exit hole on the other side without some sort of jig. How do you do that?

Skip

With the old pins and rod end removed, I insert the new rod end to the correct depth and alignment.  Set it in “V” blocks in a drill press, drill one hole and tap a roll pin in only enough to secure it.  Drill the remaining 3 holes never passing the drill bit all the way through.  Drive out the first pin, remove the rod end, blow out the chips, reinsert the rod end, drive in new pins, flare the pin ends lightly with a centre punch.

Clarence 

[N201MKTurbo]

I have found using an end mill, to at least start the holes in something round, works well. It takes care of the drill bit walking around the sides.

[larrynimmo]

These tubes are made of high tensile steel