What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Hartzell prop bolt wire keeper damaged

D

Drippy

Well Known Member
I wonder if anyone has a solution to this issue. I have a hartzel HC-C3YR-1N/N7605 prop on my RV10 and when reinstalling after replacing the alternator belt one of the wire keepers that goes through the bolt broke allowing the nut to rotate on the bolt.

To be clear I don’t know what to call the open shaft that passes through the head of the nut to allow the safety wire to pass through. I also assume it it keeps the head of the bolt(nut) on the bolt shaft.

Is there a way to replace these keepers?

Thanks for any help.
 
Cotter Pin

Cotter Pin?
Better find an A&P or another builder. They will have the parts and torque wrench.
 
If I understand what you’re saying, that’s a roll pin that connects the nut to the threaded, “headless” bolt. I’ve never replace on, but it should be fairly simple - measure the diameter of the hole, by that sized roll pin, drive the broken pin parts out with the appropriate sized drift, and drive the new pin in place. Go slow, think about each step, and it should work.
 
Roll pin

Ironflight said:
If I understand what you’re saying, that’s a roll pin that connects the nut to the threaded, “headless” bolt. I’ve never replace on, but it should be fairly simple - measure the diameter of the hole, by that sized roll pin, drive the broken pin parts out with the appropriate sized drift, and drive the new pin in place. Go slow, think about each step, and it should work.
Click to expand...

Interesting. I've seen lots of roll pins and punched a few out. I didn't know there's one on the airplane.
Learned my something for the day.
 
wirejock said:
Interesting. I've seen lots of roll pins and punched a few out. I didn't know there's one on the airplane.
Learned my something for the day.
Click to expand...

And the roll pin in the latch of the fuel cap.
 
Last edited:
Worse case you pull the prop back off and take it over to a local prop shop to fix the bolt for you. Wouldn’t be expensive and then it would be fully trusted.
 
Drippy said:
I wonder if anyone has a solution to this issue. I have a hartzel HC-C3YR-1N/N7605 prop on my RV10 and when reinstalling after replacing the alternator belt one of the wire keepers that goes through the bolt broke allowing the nut to rotate on the bolt.

To be clear I don’t know what to call the open shaft that passes through the head of the nut to allow the safety wire to pass through. I also assume it it keeps the head of the bolt(nut) on the bolt shaft.

Is there a way to replace these keepers?

Thanks for any help.
Click to expand...

So your prop has an "R" flange (C3YR). Table 3-1 on page 3-8 of the Hartzell Propeller Owner's Manual (Linked below) calls out the spring pin (aka roll pin) to be P/N B-3842-0750.


i-ZmVfSzj-S.jpg


It appears to be available from Ottensen Propeller Accessories and lists it as 3/32".

 
Last edited:
If the pin is broken, you will likely struggle to drive it out unless you got clean breaks with the two outter parts full broken off. You can double nut the the other side and get the stud out of the nut, but may damage the threads, so I would have a spare stud and nut along with the roll pin when doing the job. Good news is the tension pin is not necessary to get good torque on the fastener. Bad news is you can no longer safety wire the nut.

If you do it yourself, the new tension pin should be installed with the seam 90* from the rotational axis of the stud.
 
Last edited:
I would imagine a broken piece is still in the bolt so the first step would be to rotate the head and run the pin punch through to make sure the channel is clear. If the entire center section of the pin is in the bolt that might be tough with the prop on the plane. With the prop on the bench, pull the bolt from the head, clean out pieces from the bolt and the head, then reassemble with a new pin before returning the assembly to the plane.

Does anyone know if a new bolt and head should be used? When I had a hub replaced I think the shop used new bolts and heads instead of reusing the old ones.

I’d probably let the prop shop do it but they are only a short drive for me here.
 
Still be nice to know why, or how, it broke. Considering most have never heard of one breaking, it might save someone else from the hassle.
 
I've seen it 2 or three times (I'm an IA), it usually sheared the roll pin when removing the "bolt" (castellated nut and stud forming a captive bolt),a result of being over torqued. In each instance I was able to remove the remnants and replace the roll pin, on engine, in place.
 
Last edited:
How it broke

I am not sure but full accept I may have over torqued it some time in the past but was in the initial turn with the torque wrench this time.

I ordered replacement pins and thanks for the removal advice as yes the remnant remains in there.

Also thanks for the 90 degree to rotation info I will do my best.

Thanks again everyone
 
Caution!

Simply replacing the roll pin is likely not sufficient! Those nuts and studs are also bonded together. If the nut was rotated enough to break the roll pin, then the bond has almost certainly also been compromised. This should be repaired by renewing the bond as well as the roll pin, and ensuring that the hardware has not been otherwise damaged and replacing as needed.

A prop shop is best suited to perform this repair. Please contact our product support group if you have any questions [800-942-7767 (Option #3)].
 
TParker said:
Simply replacing the roll pin is likely not sufficient! Those nuts and studs are also bonded together. If the nut was rotated enough to break the roll pin, then the bond has almost certainly also been compromised. This should be repaired by renewing the bond as well as the roll pin, and ensuring that the hardware has not been otherwise damaged and replacing as needed.

A prop shop is best suited to perform this repair. Please contact our product support group if you have any questions [800-942-7767 (Option #3)].
Click to expand...

There we go.
This site is absolutely the go to for all things RV but I think we sometimes jump to help without fully understanding the problem, and, more importantly, the correct solution.
 
repair complete

Sorry for the delay in posting an update, but I have been waiting for parts.

I beyond the advice provided in the forum I also called Hartzell and got great support from their technical staff.

Quick summary of the repair:

After removing the prop I double nutted the stud and removed the head.

I replaced the stud and head, reinstalling using Locktite 675 (Red), per the Hartzell's directions. I was nervous about driving in the roll pin, though I did find it easier to get the roll pin after I used a washer and nut to hold the stud in place.

I then let the locktite setup for a few days and just reinstalled the prop today.

Thanks for the help.
 
You must log in or register to reply here.
Back
Top