Gear Rigging

[N201MKTurbo]

6 hours ago, RLCarter said:

No bungees on the nose retraction tubes, not sure what's going on, I can get the 2nd bolt in, it just takes more force to do so

I just looked and you are correct there are just rods on the E. My J has bungees on the nose retraction links.

 

[Sabremech]

9 hours ago, RLCarter said:

Spent the last few days looking over the manual gear system trying to find the cause for the excessive amount of force it takes to release and lock the j-bar handle from the gear down lock. To eliminate as much as possible all gear doors have been disconnected, the new LASAR lock block helped some but it was still just shy of a two handed operation when rigged. Two things that got my attention are as follows:

(1)  With all 4 retraction links disconnected at the J-bar, the bar does not go the last 3/8” to 1/2” forward so the handle will slide into the “Gear Down” lock with out a little forward pressure. This was not noticed before due to the fact that the 2 Bungee assemblies are still attached to the J-bar forcing it towards the floor. The bungees relax allowing the J-bar to become very easy the last inch or so before getting to the gear down lock. By pushing with one finger on the J-bar just below the handle and holding the release button with my other hand the handle snaps in place fully, the J-bar is hitting the plastic around the nose wheel well. Most of the older Moonies I have seen have carpet around the nose wheel well which is thicker than the plastic. So how much clearance should there be?

(2) The rigging procedure calls for getting “Zero” Pre-load, then shortening the 2 retraction tubes going to the nose wheel. When set at “Zero” both bolts move freely in the rod-end bearings, when the tubes are shortened equally 2 turns the last of the 2 tube is difficult to install the bolt. I have checked and both rod-end bearings have the same thread pitch. The other (forward) ends of the nose wheel retraction tube have the eccentric bushings, could these cause the retraction tubes to not line up if the bushing are not set the same?

Hi RL, 

What you describe in your first statement is identical to what I had happening with my j bar. With a bent bar, you end up over rotating it to get it into the downlock where the bar is contacting the nose wheel well. I'll try to dig up a picture of mine I took that showed that over rotation and it hitting not only the wheel well but the shield covering the fuel line under the floor. I really suspect your j bar is not straight. 

[RLCarter]

18 minutes ago, Sabremech said:

Hi RL, 

What you describe in your first statement is identical to what I had happening with my j bar. With a bent bar, you end up over rotating it to get it into the downlock where the bar is contacting the nose wheel well. 

How much was yours bent? I removed the chrome handle and checked the entire length of the bar, maybe 0.005" off at the most is all I see. Headed back out after lunch to check at the eccentric bushings also going to check the small bungees in the main wheel wells to se if they are "coil bound"(several coats of paint). The one thing I don't want is the J-bar to break, so it will stay on the jacks till it gets resolved.

[Marauder]

39 minutes ago, RLCarter said:

How much was yours bent? I removed the chrome handle and checked the entire length of the bar, maybe 0.005" off at the most is all I see. Headed back out after lunch to check at the eccentric bushings also going to check the small bungees in the main wheel wells to se if they are "coil bound"(several coats of paint). The one thing I don't want is the J-bar to break, so it will stay on the jacks till it gets resolved.

Could the attachment point be bent a bit as well? I can't recall what or how a J bar attaches, but wonder if the bracket that it pivots on could be bent a little from people tugging on the bar.

[Sabremech]

3 hours ago, RLCarter said:

How much was yours bent? I removed the chrome handle and checked the entire length of the bar, maybe 0.005" off at the most is all I see. Headed back out after lunch to check at the eccentric bushings also going to check the small bungees in the main wheel wells to se if they are "coil bound"(several coats of paint). The one thing I don't want is the J-bar to break, so it will stay on the jacks till it gets resolved.

Your bar should go smoothly into the down lock block with all the rods disconnected. The bar tends to be bent towards the very bottom where it attaches to the cross bar. 

I'll look at my old thread and see if I can move some of the pictures over to this thread. 

David

[RLCarter]

David,

I bounce over to your thread on this issue and have seen this pictures. What you are saying is yours was bent at the small section of tubing that is welded (at an angle) between the cross bar and the tubing that is inside the cabin? 

[Sabremech]

3 hours ago, RLCarter said:

David,

I bounce over to your thread on this issue and have seen this pictures. What you are saying is yours was bent at the small section of tubing that is welded (at an angle) between the cross bar and the tubing that is inside the cabin? 

Hi RL,

 Not bent at the small section of tubing, but at the bottom of the main handle down low. That bend will force the small section of tubing at an angle you are talking about further into the wheel well and the floor. Once mine was straightened, I had clearance between my wheel well and J bar. and the handle went freely into the downlock.

 Mine was a two handed operation to get the gear to lock down and after the repair, a smooth one handed operation as it should be. 

 What thread did you find my J bar pics in? i can't seem to locate it now. Thanks.

 David

 

Edited January 14, 2017 by Sabremech

[RLCarter]

Checked the eccentric bushing on the nose wheel retraction tubes, all 4 are at 12 O'clock. All 4 retraction tubes were removed from the J-bar, the nose wheel tubes were shorted 2 turns and re-installed and the mains were left at zero preload, J-bar was rotated forward (gear down) and once again could not see anywhere that it was touching except on the plastic as before. Removed the J-bar for a much closer inspection, can't see anything, one thing I did notice that there is a weld bead on both the short tube and also on the lever at the miter joint, you can also see the black paint is rubbing off from coming in contact with the plastic around the nose wheel well. Hopefully I will get another set of eyes on it tomorrow.

[RLCarter]

David this is the tread I have read Johnson Bar Issues

[Sabremech]

3 hours ago, RLCarter said:

David this is the tread I have read Johnson Bar Issues

Thanks for that RL. Looks like I never posted a photo of the bend in the bar. I'll have to dig in my computer for a picture or two. 

Your problem looks identical to what I had. I'll do my best to dig up the photos to see if they offer any help for you.

David

[RLCarter]

Some progress, but some set backs as well. Reinstalled only the J-Bar, all 4 retract tubes and both bungees are completely off and on the workbench, I also removed the plastic from the nose wheel well. With everything removed J-bar swings easily up into the gear lock block and down into the lock on the floor (floor has never been an issue). One thing that I had noticed is the nose wheel retracts too far into the wheel well and the tire drags slightly, knowing that something was not right I went ahead and removed the retracting truss assembly to check it out more closely and rotate the eccentric bushing so it would go as far into the wheel well. I ended up removing the truss twice (its a lot easier jacking with the eccentric bushing on the bench rather that on the airplane). Each time I rotated the bushing the front retraction tubes were installed and the gear was swung to check for interference, with the tire no longer rubbing I noticed that one of the retraction tubes would rotate and the other one would not (this is with the gear retracted and locked in), I lowered the lowered the gear with the J-bar and both retraction tubes spun freely and the bolts (rod end bearing at the J-bar) slid in effortlessly. I removed bolt on the one of the retraction tubes and raised the gear, then I moved the loose retraction tube up into place and it was just shy of 3/16” from the holes all lining up. The truss was removed and verified that all 4 eccentric bushing were in the same location (which they were) so I started looking for something bent, in my drawing (exploded view) the red colored tube is not in alignment with the other, it’s a pain to sight across to the other tube, but they are out from each other approximately an 1/8”, looking from one side the other side goes down, flip it around and the other side goes up, the other thing is one retraction tube the rod end bearing is screwed all the way in while the other has about 5 or 6 threads showing which would make it impossible to shorten the one rod 2 turns for the starting point on the preload…….Side note: all the above was only the nose wheel, no mains and no bungees, and the J-bar was easily locked and unlock from the gear down lock under the panel while sitting on the wing walk and reaching in the cabin

 

Edited January 17, 2017 by RLCarter

[N201MKTurbo]

If you have it apart that far, for gods sake, strip it and repaint it!

Ok, I'm out of town n a bar with a few beers. That was a little harsh, but wouldn't your plane look awesome with a freshly painted J bar?

Edited January 17, 2017 by N201MKTurbo

[RLCarter]

Facts are facts....... The whole gear system needs painting, paint, reducer, tape and gun all setting on the bench, new crushed walnut shells in the blast cabinet, just don't want spend the effort untill I know it's a serviceable part

[MB65E]

Check to make sure your nose retract tubes are not bent. Mine had a nice bow in the right tube. 

Might take that upper truss assembly and look for cracks. Blasting the piece will save you some time of messing with a cracked part. I would almost see if you could source one from a known vendor. Several recent gear up have had nose gear issues. 

Keep digging- your close!!

-Matt

[RLCarter]

4 minutes ago, MB65E said:

Check to make sure your nose retract tubes are not bent. Mine had a nice bow in the right tube. 

Might take that upper truss assembly and look for cracks. Blasting the piece will save you some time of messing with a cracked part. I would almost see if you could source one from a known vendor. Several recent gear up have had nose gear issues. 

Keep digging- your close!!

-Matt

Retract tubes (nose wheel) are straight, they got cleaned up and painted today, going to give LASAR a call in the morning

[RLCarter]

On January 16, 2017 at 11:48 PM, N201MKTurbo said:

If you have it apart that far, for gods sake, strip it and repaint it!

Along with several other pieces the bungees were cleaned, stripped and now have a fresh coat of epoxy paint. MM says bungees get lubed with "Low Temp Oil", I can't see using an oil (Tri-Flow) on the Rod ends but what type of grease should be used on the sliding portion of tubes?

[N201MKTurbo]

3 minutes ago, RLCarter said:

Along with several other pieces the bungees were cleaned, stripped and now have a fresh coat of epoxy paint. MM says bungees get lubed with "Low Temp Oil", I can't see using an oil (Tri-Flow) on the Rod ends but what type of grease should be used on the sliding portion of tubes?

I use the same stuff I use on the rod ends. I lube them with the gear partially up so I can exercise the sliding part so I can work the lube in and the crud out.

[RLCarter]

All cleaned up and painted, J-bar installed and moves freely into both lock blocks. Nose wheel retract truss installed, along with retract rods and bungees. Waiting on a couple of bushings from LASAR for the mains, then set the preloads and hopefully be able to get the J-bar easily in the gear down lock block.

[RLCarter]

UPDATE:
 After 3 re-orders (wrong parts) finally got the the gear working MUCH MUCH better. New bushings and hardware in the main gear did the trick, there was barely any play (few thou) in the individual pivot points but by the time they all added up it was enough to make the difference. The mains are at 255 in-lbs each and the nose is 115 in-lbs. I can now sit on the wing-walk and reach in with my left hand and cycle the gear, and from the left seat its really a breeze. I had added all the plastics that enclose the nose wheel well and knew the J-Bar was touching the plastic when the gear was extended (wasn't the issue), so while I waited for the next wrong order I slotted the plastic so it wouldn't eventually crack a few years from now when it gets brittle.