Head of Zerk fitting snapped off from prop hub

[n567vb]

I was doing the annual propeller maintenance today. I removed the zerk fitting to add more grease. While removing, the head of the zerk separated from the threaded portion of the zerk. Now I have the threaded portion of the zerk stuck in the hole in the prop hub. Any suggestions on how to get it out? I?d hate to have to drill it out and potentially get metal shaving inside the prop hub.

Also, anyone know if the hole is imperial or metric? I plan on replacing with a plug instead of a zerk, but not sure if it?s a 1/4 inch or 6 mm hole size.

I hate it when what should be a simple job becomes a huge ordeal!

Thanks
Vince
RV-7

[DennisRhodes]

Try an Easy Out.

[Kyle Boatright]

An ez-out is the tool of choice. But I'm curious about why you were removing the zerk? Those are one way valves, intended for the purpose of adding grease.

[Tracer 10]

Remove Zirk that is opposite from leading edge of prop & grease opposite zirk with Aeroshell #5. Grease should go from leading edge to trailing edge of prop..!!

[propjoe]

Use a Hartzell PN 106545 plug once you get the MFer out. Off the top of my head the hole is 1/4 x 28 with a 1/8 pipe thread zerk installed. Makes sense right???
http://hartzellprop.com/wp-content/u...-354-R00-W.pdf
I like Left handed Cobalt drill bits. Pack the flutes with grease and go slow. Break off the bit and you will be in a world of shyt... If your not comfy with the drill, remove the prop and take it to a prop shop. Little heat (less than 150° F) may help once Dis-assembled.
I keep one of these kits in my car. They are great for the sizes that most standard SAE fasteners are broken off and handed to me, after they are snapped off both at work and other areas I frequent:
https://www.ebay.com/p/1465394646?ii...IaAvVYEALw_wcB
Here is where to get replacement lefty cobalt drills:
https://www.mcmaster.com/cobalt-stee...and-drill-bits

Edit: If you booger the hole and this is a newer "A" or "B" suffix hub you can install a 1/4 x 28 "Slimsert" into the offending hole with the knurling ground off and loctited into place. Slimsert is approved and in the manual. If it is the older hub... I got nothing if you booger the hole.

Edit #2: Use the owners manual for Instruction for Continued Airworthiness. There is a bunch of info here. Lubing of prop starts on page 6-5:
https://hartzellprop.com/wp-content/...000-R23-WA.pdf

[n567vb]

I tried the ez out, but it wasn't working. I'm going to try one more time with some penetrating oil to see if that helps. I worried that the head snapped off because the threads were bad which is keeping it from coming back out with the ez out.

Worse case, since the shaft of the zerk is hollow already, I'm wondering if I might be able to just tap the hole and put a plug if if I can find something the right size.

[BillL]

Originally Posted by n567vb

I tried the ez out, but it wasn't working. I'm going to try one more time with some penetrating oil to see if that helps. I worried that the head snapped off because the threads were bad which is keeping it from coming back out with the ez out.

Worse case, since the shaft of the zerk is hollow already, I'm wondering if I might be able to just tap the hole and put a plug if if I can find something the right size.

If it is broken off with a square edge, I would take a drift and tap it axially to get its attention then heat the hub to warm to the hand and retry the ez-out. penetrating oil is not going to do a thing. You can take another out and measure it. Then know what size drill will enlarge and relieve some stresses. Then, it may allow a larger EZ out. Left handed bit is a plus. Don't forget to smack it with a punch - a smaller hammer is better, you want shock, not force. It is a common technique with steel in aluminum and it has been quite effective. Save it to last if unsure, just not after breaking the ez-out.

[tturner]

I had the same problem. My prop was one year old and I was doing the first service on it when one of the zerk fittings broke off. I tried an easy out and it broke off in the zerk fitting. At this point, I sent it to a prop shop where they disassembled the prop and sent the hub out to a machine shop to remove the fitting. Hartzel now ships props with a grease fitting on one side and a plug on the other side. You remove the plug to grease the blade and no longer have to remove the zerk fitting. A zerk fitting is much easier to shear than a plug.

[BobTurner]

I am by no means an expert, but I would try to drill and tap the hole for a left handed thread (use lots of grease on the tools to try to capture all chips). Insert a left handed bolt coated with heat-breakable locktight. Go as tight as you dare, and if the zerk backs out, good. Otherwise, leave the whole assembly, and next year pull the bolt (mark it as left hand!) to let old grease out.
Not sure if there?s enough weight to re-balance the prop.