Rotor head bearing bushing

jany77

Member
Joined
Jul 13, 2008
Messages
573
Location
central california
Aircraft
cessna 150,172,182,trikes,ul
Total Flight Time
over 2000
Is there any trick how to install the bushing inside the main bearing without using force ,when I was installing the bearing I had it in freezer and the housing I put in oven for 200 degrees for about an hour ,but I'm worry about the seal on bearing ,it might melt or it can suffer other damage in oven ,any ideas .Thank you
 

Attachments

  • photo127358.jpg
    photo127358.jpg
    92.7 KB · Views: 4
  • photo127359.jpg
    photo127359.jpg
    74.4 KB · Views: 4
Jany77, Don't know what your clearances dimensions are, but you can get the temp differential by instead of heating the bearing, get a small piece of dry ice and cool the bushing with that. Just remember that you will have a hard time getting the bushing back out if you need to replace the bearing in the future.. Just make sure you support the inner race when you press the bushing in place.

Dave
 
It's unusual for there to be an interference fit between the bushing and the inner race. I don't see a need for it.
 
If needed...
Place the Bushing in the freezer.
Preheat the oven to the "WARM" (~175°) setting.
Turn OFF the oven just before placing the Bearing in.
As the oven cools, the bearing will heat to ~150°.
This will be too hot to touch, but not more than the seals can handle.

Again, be sure to support the INNER RACE when you press the bushing in place.
 
I did the same think with the bearing ,put it in freezer for 3 hours and put the housing in oven on 200 for an hour ,when I removed the bearing from freezer it just drop in ,this is bensen rotor head I had to take appart for prerotor ring install ,when I was in it I decide to replace the bearing since it had some surface rust on it ,so I doubt that the bushing is wrong size ,I used mrc 5206 czz bearing ,the bushing is just bid big to slide it in by hand ,I had to use mallet with solid rod to remove it from the old bearing but without any brutal force. I was able to remove it without any damage ,since I live in apartment I'm not sure if any of this will work I don't want to get in situation where the bushing drop half way in and the rest will get stuck ,it might worth it to drop it at machine shop and have them take few thousands off maybe 0.002 .
I will try the same method like I did with the bearing and housing but I use the recommended method with preseting the oven to 175 and the turn it off .
Thank you guys
 
Removing 0.002" may make it so loose that you will need to use Loctite to keep it from rattling.
0.002" is Huge in the pressfit world. Did you mean a few ten-thousands? 0.0002
A few minutes with ultra fine sandpaper may all that is needed to clean up the surface.
Aluminum tends to "Stick" to steel. A little Oil may help during insertion.
Aluminum expands/contracts at twice the rate of steel.
Cooling the Aluminum part will have twice the effect of heating the steel part.

This is not a large part.
If you have a 5-6" vise, it can serve double duty as a press to insert the bushing.
 
Yes I meant 0.0002 ,I measured the bearing opening which came to 1.180,and I measured the bushing ,it came to 1.181 so I try again the freezer method and wise ,I hope it will work thank you
 
Top