removing and installing new bushing for control stick

67MK Larry · #1 05-05-2009, 02:04 PM

Anyone removed old bushing and installed new one in contol stick. Looking for options. Thanks

Randy · #2 05-05-2009, 04:41 PM

Not yet, but I hope when I do it will take the slop I hear and feel out of the elevator movement in the stick.

fl-mike · #3 05-05-2009, 09:38 PM

Quote:

Originally Posted by Randy

Not yet, but I hope when I do it will take the slop I hear and feel out of the elevator movement in the stick.

It's more likely that the slop is in the elevator bellcrank bearing. Fairly common and it doesn't take much to be able to hear a little "click". Took me forever to isolate it. Lots of checking rod end bearings and pushrod clearances. Of course, then the veterans told me "Yeah, they do that. Don't worry about it."

az_gila · #4 05-05-2009, 11:21 PM

Quote:

Originally Posted by fl-mike

It's more likely that the slop is in the elevator bellcrank bearing. Fairly common and it doesn't take much to be able to hear a little "click". Took me forever to isolate it. Lots of checking rod end bearings and pushrod clearances. Of course, then the veterans told me "Yeah, they do that. Don't worry about it."

...just changing the bolts to NAS close tolerance bolts can take out a few 0.001's of an inch and make a difference.

Depending on the AN bolt tolerances --

Approx. 0.0005 to 0.0035 larger diameter for AN3 and AN4 bolts

DanH · #5 05-06-2009, 05:47 AM

<<just changing the bolts to NAS close tolerance bolts can take out a few 0.001's of an inch and make a difference.>>

If the bolt is an axle....and it is not supposed to be an axle. Bearing centers should be clamped.

edbooth · #6 05-06-2009, 09:00 AM

Immobilize the push rods and check the stick again for slop. If the stick is tight, then it's probably in the end bearings if installed correctly...as Dan says, the bolt should clamp the inner bearings tight, so any movement would be actual bearing wear.

Ed Booth, Trenton, SC

67MK Larry · #7 05-06-2009, 09:15 AM

I didnt go far enough, /there us a lot more play in left stick vs right stick. When I did condition inspection last year, with floor boards pulled you can see the excess play at stick. Vans said its the bushing and I purchased bush and new bolt. My question is, what is best way to get old out and pressing new in. I have never done something this small before, Im thinking abor press with bolt or rod slighlty smaller than bushing od and carefull pushing out, thinking I shoulheat the stick with heat gun first. Any suggestions would be appreciated. We checked the rest of control system at annual, everything else was tight. 1994 RV-6A 560 hours ttaf. Going to replace nose fork and shaft at same time, not looking forward to this. Thanks Larry

Lycosaurus · #8 05-06-2009, 09:25 AM

Quote:

Originally Posted by 67MK Larry

I didnt go far enough, /there us a lot more play in left stick vs right stick. When I did condition inspection last year, with floor boards pulled you can see the excess play at stick. Vans said its the bushing and I purchased bush and new bolt. My question is, what is best way to get old out and pressing new in. I have never done something this small before, Im thinking abor press with bolt or rod slighlty smaller than bushing od and carefull pushing out, thinking I shoulheat the stick with heat gun first. Any suggestions would be appreciated. We checked the rest of control system at annual, everything else was tight. 1994 RV-6A 560 hours ttaf. Going to replace nose fork and shaft at same time, not looking forward to this. Thanks Larry

Larry,

The bushing and bolt do not rotate. The stick rotates around the busing. The bushing is cut so it is just a tad longer than the stick's 'receptacle'. It should be easily removed, as it is not a press-fit (or at least should not be a press-fit).

What has probably happened is that the stick's 'receptacle' was not reamed properly, or made too large. The bushing's fit is therefore sloppy, accounting for the excess play you are seeing.

New bolt and bushing from Van's may not solve your problem, unless it was created by wear during use. You may need to make a custom bushing with a slightly larger outer diameter that would provide a tighter fit.

az_gila · #9 05-06-2009, 09:26 AM

Quote:

Originally Posted by DanH

<<just changing the bolts to NAS close tolerance bolts can take out a few 0.001's of an inch and make a difference.>>

If the bolt is an axle....and it is not supposed to be an axle. Bearing centers should be clamped.

...I was typing too late at night, and looking at too many non-RV experimentals...

My comment is relevant for the locations that use castle nuts and cotter pins as Dan says.

However, even the clamped bolts can move under load if the hole is not a good fit and the bolt torque is at the low end. At a lot of our control system joints there is a large (in the order of 8:1) mechanical advantage. If someone hold a control surface fixed, and loads the stick as a test, these bolts could possibly move around in their slightly oversize holes.