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Anyone else seen lateral play in F-633-L/R control column bearings?

jmjula

Well Known Member
On my fifth condition inspection, I've noticed that my control column has a lateral play left/right of a ~1/16th" now. The bearings in F-633s are not popping out, but it appears they might eventually if left as is, so I will be replacing them, that should be some fun! Curious if anyone else has seen this? Maybe I just do too many barrel rolls ;)

https://drive.google.com/file/d/1oBSWn_6wdnsXqD-4BSajSyg27Dsr4OW7/view?usp=sharing

James
 
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thought

I think those bearings are retained with Loktite bearing retainer #609.

I'd say, disassemble, clean, inspect the bearings, and if OK reinstall with 609. Leave to set the required time w/o moving them.

I wouldn't delay. They are just going to wear the aluminum and be less likely to stay retained if the fit gets too sloppy.
 
On my fifth condition inspection, I've noticed that my control column has a lateral play left/right of a ~1/16th" now. The bearings in F-633s are not popping out, but it appears they might eventually if left as is, so I will be replacing them, that should be some fun! Curious if anyone else has seen this? Maybe I just do too many aileron rolls ;)

https://drive.google.com/file/d/1oBSWn_6wdnsXqD-4BSajSyg27Dsr4OW7/view?usp=sharing

James

that doesn't appear bad to me. at least you know it's not binding.
 
Sure the bearings are actually moving? Or is the bolt & washer stack not tightened. Plans do call to add washers as required to take up slack.
 
The bearings in the F-633s are loose now. They shift right/left and can rotate within the press fit outer ring. The outer most ring appears secure. I’m pretty sure the only thing that should rotate is the center ball. I’ll have another discussion with Vans tomorrow, perhaps this is the way these work once broken in?

https://drive.google.com/file/d/1veExD_4WsOcxJiyRqDSzcjfcE1QEGVcQ/view?usp=drivesdk

You are correct. The outer "ring" should be press-fit in the bracket, and only the center part of the bearing should move.

You'll need to replace those bearings, and make sure the outer edges don't move. Either press fit, or if the hole in the bracket is too large from wear, perhaps new brackets as well. Then lube the bearings each year during the Annual Condition Inspection.
 
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The bearings in the F-633s are loose now. They shift right/left and can rotate within the press fit outer ring. The outer most ring appears secure. I’m pretty sure the only thing that should rotate is the center ball. I’ll have another discussion with Vans tomorrow, perhaps this is the way these work once broken in?

https://drive.google.com/file/d/1veExD_4WsOcxJiyRqDSzcjfcE1QEGVcQ/view?usp=drivesdk

The outer ring is the race and it should be held captive. The inside is held captive to the bolt it should rotate inside the race. The bearing cage is that thin middle ring. THose bearings cannot take any axial load, only radial. If you didn't have things shimmed well, the edges of the bearing and race will wear fast. I had to replace an alieron hinge (same as this one) because I didn't shim one very well and it got quite sloppy. Nowhere near as bad as yours though. IMHO with these bearings, your shims need to be within a few thou of the gap / clearance.

Larry
 
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I had these shimmed as close as one can get given the working area, but there is always a chance I was slightly off. I even went with two thin washers instead of one thick washer in one case because of the thousandths of difference between the two was what was needed. Being an engineer myself, I have an attention to detail that usually means I aim closer to perfection rather than good enough. Lube definitely wasn't the issue either, that center ball was turning freely and still was partially lubed since last annual. There is no play in the center ball and its race, only between the middle ring and the press fit outer ring. This appears to be due to the lateral load on the bearings, of which I'm pretty sure they are not designed for.

I likely do many more barrel rolls than most, maybe a contributing factor, maybe not. I'd be really surprised if I am the only one with this issue, it was small enough of play that I almost missed it...luckily these were not that difficult to remove from the plane, and I will be watching what happens with the new/fixed set even more closely. Replacing is easy enough other than the work involved in either prepping completely new F-633s, or figuring out how to press fit new bearings. Van's also suggested staking the bearings might be good enough to fix this.

Thanks for all the replies!
 
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lateral play in ailerons

I had some play in mine, so i wound up replacing the column bushings and putting in precision bolts all the way out and eliminated the play.

Keith Rhea
RV7
2021 donation
 
F633 bearings

hello, I needed to replace my column bearings at a little over 800hrs., the outer shell of bearings were loose in the F633's. They were originally pressed and staked in place. I replaced just the bearings using JB weld glue to take up clearances and staked in place. I worked hard when originally built to install them correctly with no side loads on bearings and thought maybe the conical mounted engine produces more vibration working against them?

RV6A
 
Interesting David. I took a hammer to one of the bearings to see if I could pop them out, and the answer is NOT easily. I haven't tried the 5lb hammer yet though. I ended up buying new F-633s once I realized replacing just the bearing is not going to be straightforward. Staking might have bought some more time, but I damaged one of them beyond use investigating.
 
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