StanFoster
09-24-2006, 04:22 PM
I have 108 hours on my SparrowHawk and thought I better quit flying and check those upper crankshaft support bearings. I had two on hand because I wanted to completely take them out and inspect them...and no matter what...the new ones were going in. It takes a few hours to do this. The SparrowHawk 11 has a much easier change out system.
I posted some pictures here for anyone getting ready to change theirs.
I first took the propeller off and then removed the drive belt. I have a handy little 9/16 socket on a small breaker bar for this. I ground down the socket so it goes inside the lower pulley.
There are two little 1/16 inch roll pins that have to be driven down between the bearings. I used a 1/16 inch drill bit for this.
Next I needed a puller of some type. I went to the local aircraft mechanic...no luck. Then to the tool rental place. no luck. My last resort was to the farm shop and make my own puller. Its not pretty...but did it ever do the trick. I found a flat iron 1/2 inch thick by about 4 inches wide and over a foot long. I simply torched a hole through the approximate center so that a 3/8 inch bolt could slip through. I then bought a 4 inch long 3/8 fine thread bolt and put it through my "puller" and then screwed it into the inner collar that goes through both bearings.
3 kerwhomps with this ugly beast and the bearings and collar were out.:whoo:
My bearings looked and felt absolutely as good as the new ones...but it would be foolish to reuse them. I want my clock to start with 0:00 hours....not 108.
The rest was easy reassembly until I had to place those tiny 1/16 inch roll pins inside the pulley. I took another pair of hands...a flashlight in my mouth...and after it took 20 minutes for the first one...but we had our technique down and the next one took 20 seconds.:whoo:
It was a real quick reassembly after that. This whole process including running to the tool rental place....the airplane mechanic...and finally just designing and fabricating my own puller took 4 hours before it was all back together. I know I could do in in an hour and a half next time.
Heres the pictures...
1st. the upper bearing rear plate off
2nd the prop off
3rd the 1/16 drill bit drive out tool
4th the "puller" ugly but works great
5th first new bearing and in between collar installed
6th second bearing in
7th done:D
I posted some pictures here for anyone getting ready to change theirs.
I first took the propeller off and then removed the drive belt. I have a handy little 9/16 socket on a small breaker bar for this. I ground down the socket so it goes inside the lower pulley.
There are two little 1/16 inch roll pins that have to be driven down between the bearings. I used a 1/16 inch drill bit for this.
Next I needed a puller of some type. I went to the local aircraft mechanic...no luck. Then to the tool rental place. no luck. My last resort was to the farm shop and make my own puller. Its not pretty...but did it ever do the trick. I found a flat iron 1/2 inch thick by about 4 inches wide and over a foot long. I simply torched a hole through the approximate center so that a 3/8 inch bolt could slip through. I then bought a 4 inch long 3/8 fine thread bolt and put it through my "puller" and then screwed it into the inner collar that goes through both bearings.
3 kerwhomps with this ugly beast and the bearings and collar were out.:whoo:
My bearings looked and felt absolutely as good as the new ones...but it would be foolish to reuse them. I want my clock to start with 0:00 hours....not 108.
The rest was easy reassembly until I had to place those tiny 1/16 inch roll pins inside the pulley. I took another pair of hands...a flashlight in my mouth...and after it took 20 minutes for the first one...but we had our technique down and the next one took 20 seconds.:whoo:
It was a real quick reassembly after that. This whole process including running to the tool rental place....the airplane mechanic...and finally just designing and fabricating my own puller took 4 hours before it was all back together. I know I could do in in an hour and a half next time.
Heres the pictures...
1st. the upper bearing rear plate off
2nd the prop off
3rd the 1/16 drill bit drive out tool
4th the "puller" ugly but works great
5th first new bearing and in between collar installed
6th second bearing in
7th done:D