Stabilator Bearing

[DJ Todd B]

Does anyone know where I can get these Stabilator Bearings? Mine seems to have a lot of play.

 

[Roger Lee]

There were some CT's that had a live bearing where the center could wobble like a rodend. This wasn't a good choice. They went back to a normal fixed bearing. If yours is a standard style bearing then it can be fixed and if it's the rodend center type it can't.

You can always remove the stab which is easy. The two nuts on each side should be at 200 in/lbs. If they are lose then this would account for your fore and aft free play. If you discover you have the rotating type like a rodend go a head and check the torque on the two nuts and out it back together.

[DJ Todd B]

If I do have the Rodend type bearing,  is there any way to retro-fit the normal fixed bearing into the plane?

[Roger Lee]

I don't think so. I believe it's a different size.

[FlyingMonkey]

Mine has a little play in it, but it's up/down and almost none fore/aft.

Roger, what's the trick to get the trim tab rod ends off so you can remove the stab?  I did it before and know there's a trick to it, but can't remember it.  It's probably time to check my bearing torque.

[DJ Todd B]

Roger, assuming these are Rodend bearings, where can I get new ones to replace these?  I would figure they would have to be replaceable and replaced at some point and time. I figure if I installed new ones, the slop should be less than what I have now.

[Roger Lee]

11 minutes ago, DJ Todd B said:

Roger, assuming these are Rodend bearings, where can I get new ones to replace these?  I would figure they would have to be replaceable and replaced at some point and time. I figure if I installed new ones, the slop should be less than what I have now.

These aren't actual rodend bearings. I was just using that so you could get an idea of how that bearing was designed vs a normal bearing like on a wheel. It just has an articulating center.

[DJ Todd B]

OK, so where can I get new ones?

[Roger Lee]

41 minutes ago, FlyingMonkey said:

Mine has a little play in it, but it's up/down and almost none fore/aft.

Roger, what's the trick to get the trim tab rod ends off so you can remove the stab?  I did it before and know there's a trick to it, but can't remember it.  It's probably time to check my bearing torque.

On your SW you need to take an 8mm ratcheting box end wrenh and take the two small nuts off just inside where the stab is attached. There is one one each side of the little pin. Then just slide the rodends off. Then remove the two 10mm nuts on the bottom of the stab. Then slide the two long bolts out. Some times they will slide out and sometimes they have some corrosion from the humid climate areas. Then just unscrew then all the way out. Then the stab will slide right off in your hands. If those two bolts do have corrosion then clean them up and get the corrosion off. Before replacing them apply a very light coat of grease to help stave off more corrosion. This is really a pretty easy job. There have been a couple of times that the little pin the 8mm nuts came off of is lose and turns after you remove one nut. Just hold the bare end with a pair of vise grips and take the other nut off. Then remove the pin.  While the stab is off apply some Loctite 648 to the pin on the smooth part of the shank where there are no threads and push the pin back in place and let the Loctite set up for a while while you torque the stab pivot pin nuts. Then you can replace the stab. The torque on the two stab mounting nuts is 90 in/lbs (100 won't hurt)

[Roger Lee]

5 minutes ago, DJ Todd B said:

OK, so where can I get new ones?

Has the stab been like this since new or is this something brand new? That may answer the question. The articulating bearing was like this since new. If it was always solid as a rock and just now developed this you may actually have a bad standard bearing or just need to re-torque the bearing nuts to 200 in/lbs.

From FD unless they have some other source. Might be able to get a pair from Airtime Aviation in Tulsa. They have salvaged 5 CT's and have parts.

If yous are the articulating type it probably won't make any difference with a different set because they will be the same.

[Tom Baker]

It is called a spherical bearing.

[Jacques]

according to Parts Manual, these are  SKF 608-2RZ  bearings

 

as for changing them,, the Maintenance Manual doesn't say  much

[  replace if necessary ]  !!! ??!!!

 

Hi Roger,, glad you're back

 

[FlyingMonkey]

IIRC the lock ring holds it in place and can be removed with standard lock ring pliers, then the bearing just slides out of the housing ("bearing body" in the picture).  Not much to it.

[Roger Lee]

I'm pretty sure the spherical bearing and the standard bearing aren't interchangeable. I have a call into someone who actually tried it. Waiting for the reply.

[Roger Lee]

I did hear from my friend and they are definitely different sizes and the entire back brackets and stab mounts would have to be changed. Not something you want to do. He still has his and I believe he has way over 2K hrs. so I wouldn't worry if you have these types of bearings.

[DJ Todd B]

Thanks for Checking and reporting Roger!

 

[Jacques]

Todd,  

let us know your findings once you have the stabilator removed.

[FlyingMonkey]

On 7/6/2020 at 9:50 AM, Roger Lee said:

On your SW you need to take an 8mm ratcheting box end wrenh and take the two small nuts off just inside where the stab is attached. There is one one each side of the little pin.

This is where I have trouble...when I take the nuts off I can get one rod end off, but not the other, it jams up against the bracket and there's insufficient clearance to get it off the pin.  Does that pin float side-to-side to make more clearance?  Like I said I have done it before...but it's been quite a while.

[Tom Baker]

The pin is a press fit, but I have seen them slide before.

[Roger Lee]

The pin should be solid and not move side to side. If you tilt the stab a little one way or the other both rodends will slide off. I have never seen one that wouldn't.

 

[Tom Baker]

27 minutes ago, Roger Lee said:

The pin should be solid and not move side to side. If you tilt the stab a little one way or the other both rodends will slide off. I have never seen one that wouldn't.

 

The key word is should. Seeing that the pin is press fit it can be pulled off to one side by tightening the nut while the other side is still loose. 

[Roger Lee]

Hi Tom,

If it is already lose you can do this, but once out should be re-glued back in place with Loctite 648. It shouldn't move and it may (?) wear by moving during operations over time. If it is glued in place the rodends do their job. If that pin breaks you're in a heap of trouble.

[Tom Baker]

7 hours ago, Roger Lee said:

Hi Tom,

If it is already lose you can do this, but once out should be re-glued back in place with Loctite 648. It shouldn't move and it may (?) wear by moving during operations over time. If it is glued in place the rodends do their job. If that pin breaks you're in a heap of trouble.

The pin won't move when both rods are installed and tight. It is only when you have one nut loose and try tightening the other. It works as a kind of makeshift puller. I agree that if it is loose loose it should be re-glued. It is too loose and needs re-glued when the pin rotates when installing a new lock nut.

[FlyingMonkey]

1 hour ago, Tom Baker said:

The pin won't move when both rods are installed and tight. It is only when you have one nut loose and try tightening the other. It works as a kind of makeshift puller. I agree that if it is loose loose it should be re-glued. It is too loose and needs re-glued when the pin rotates when installing a new lock nut.

That's what I was thinking, if the nuts are tight on the rod ends they provide tension against each other to resist the pin moving side-to-side.

[Roger Lee]

But it may be able to rotate which would cause wear on the shank over time. No one knows for sure and why would you want to test that. They were solid from the factory for a reason.