Help! Can't get one prop bolt out.

markscogg · #1 12-15-2007, 05:15 PM

Hope one of you engine savvy guys knows how to solve this problem.
I was trying to remove the prop from my RV-4 due to a cracked spinner bulkhead. One bolt didn't want to come out.
At first it would back out a half turn, then get tighter. I used a lot of penetrating oil, wiggling, and gradually moved the bolt in and out until it was about 1/4" out. Heard a pop at this point. I think this was the 5/8" bushing coming loose between the crank and prop spacer. You can see that the bushing turns now, when you turn the bolt. (Looking thru the space you get when you pull the prop forward 1/4".)
Sensenich aluminum prop, 4" of spacers and 3/8" prop bolts about 8" long.
Thanks in advance for your advice.

DanH · #2 12-15-2007, 06:50 PM

Mark,
Sounds like the threads are badly galled. Both the bolt and the bushing are ruined. Pull the prop and spacer forward, then hacksaw through the bushing and bolt threads in the 1/4" gap. Remove the prop, press out the stub, buy a new bushing and bolt.

I hope the bushing isn't hardened. Never tried to cut one.

If you keep turning the bushing you'll enlarge the hole in the crankshaft flange and lose the press fit. For sure you don't want to do that.

az_gila · #3 12-15-2007, 07:46 PM

Quote:

Originally Posted by DanH

Mark,
.....
If you keep turning the bushing you'll enlarge the hole in the crankshaft flange and lose the press fit. For sure you don't want to do that.

If the hole is slightly enlarged, it's not a disaster, the bushings do come in oversize dimensions...

Some details and part numbers here...

http://www.lycoming.textron.com/supp...fs/SI1098G.pdf

gil A

rvbuilder2002 · #4 12-15-2007, 08:25 PM

Quote:

Originally Posted by DanH

Mark,
Sounds like the threads are badly galled. Both the bolt and the bushing are ruined. Pull the prop and spacer forward, then hacksaw through the bushing and bolt threads in the 1/4" gap. Remove the prop, press out the stub, buy a new bushing and bolt.

I hope the bushing isn't hardened. Never tried to cut one.

If you keep turning the bushing you'll enlarge the hole in the crankshaft flange and lose the press fit. For sure you don't want to do that.

I agree with Dan, the bolt and bushing are burnt toast.

My suggestion though, would be to cut the head off the bolt (disc in die grinder or hacksaw). This will make it less likely that you will mess up the prop or ring gear support, and the prop will stay in place by itself on the stub of the bolt until you slide it off. You will have to make a second cut to remove the bolt, but I think it would be safer.

markscogg · #5 12-15-2007, 08:26 PM

Thanks for the help guys.
I could cut the head off the bolt. That way I could slide the prop off. Then cut the bolt again, near the bushing.
Will the bushing and the rest of the bolt could come out the back?
Can it all be done with the engine in place?
According to the Service Instruction:
Tool No. ST-115 is used to remove and replace all propeller flange bushings. Can that be rented or done some other way?
Thanks

markscogg · #6 12-15-2007, 08:31 PM

Quote:

Originally Posted by rvbuilder2002

I agree with Dan, the bolt and bushing are burnt toast.

My suggestion though, would be to cut the head off the bolt (disc in die grinder or hacksaw). This will make it less likely that you will mess up the prop or ring gear support, and the prop will stay in place by itself on the stub of the bolt until you slide it off. You will have to make a second cut to remove the bolt, but I think it would be safer.

Looks like Scott and I were typing the same thing at the same time, so ignore the first part of my last post.
Still wondering about the other questions, though.
Thanks

Mel · #7 12-15-2007, 08:36 PM

Mark,
I have removed these before with a short piece of 4130 tubing, a bolt and a large washer. I also have a few extra 3/8" bushings that I removed from a new engine to replace with 7/16" bushings. If one of them will work, you're welcome to it.
Call or e-mail me tomorrow and we'll talk.
972-784-7544 n168tx(at)flytx.net

rvbuilder2002 · #8 12-15-2007, 08:46 PM

Quote:

Originally Posted by markscogg

Looks like Scott and I were typing the same thing at the same time, so ignore the first part of my last post.
Still wondering about the other questions, though.
Thanks

Once you cut the bolt close to the bushing you can remove the ring gear support, and if the bushing is spinning as you say, it will probably tap out easily with a plastic faced hammer. Yes, this can all be done with the engine installed on the airplane.

Mel already described how to make your own tool to pull the new bushing into the crank flange hole. If you do not understand, you may need to come back for more info when you get to that point.

cropduster · #9 12-16-2007, 07:25 AM

Quote:

Originally Posted by markscogg

Hope one of you engine...
I was trying to remove the prop from my RV-4 due to a cracked spinner bulkhead. One bolt didn't want to come out.
At first...

Mark, so far I've just been lurking. This is my first post, but couldn't help jumping in here on this one. Cracked spinner bulkheads are usually caused by an out out of balance engine prop combination. When you get it back together, get someone to do a dynamic balance for you.

barryb

markscogg · #10 12-16-2007, 01:20 PM

Quote:

Originally Posted by Mel

Mark,
I have removed these before with a short piece of 4130 tubing, a bolt and a large washer. I also have a few extra 3/8" bushings that I removed from a new engine to replace with 7/16" bushings. If one of them will work, you're welcome to it.
Call or e-mail me tomorrow and we'll talk.
972-784-7544 n168tx(at)flytx.net

I got the bushing out without damage, and Mel has a replacement bushing he is sending. (Thanks Mel)
Now I need a 3/8 bolt 8 1/2 long. Anyone know where I can buy one?
This one has the letters X and S stamped on the head.
Thanks