View Full Version : Broken Stud??????

11-19-2007, 11:25 AM
When I got back from flying Sunday, I found a broken cylinder base stud on my O-235c1. Any ideas for repair/replacing it. I searched the data base but didn't find to much. I have a few ideas but would like to know what other's thought and do it right. Tom

Steve Pierce
11-19-2007, 12:21 PM
They are threaded into the case half. I would wonder why it broke also. Improper torque or fretting? Recently heard of someone finding the same thing on an O-320.

11-19-2007, 12:34 PM
Can you pull the cylinder and weld something on the stud and unscrew it?


Dave Calkins
11-19-2007, 12:34 PM
Overboost? :wink:

11-19-2007, 12:49 PM
Yes Dave that overboost on the O-235. Ha. Well I thought to take a small chisel and try an tap it out, If that doesn't work, the stud is broken flush with the base of the cylinder ,so maybe I can pull it back just enough to get a wrench on the stud and work it out?? Should I use blue or red locktite for the re-install?

11-19-2007, 12:54 PM
Radials are good for that. Done a few. Pull the cylinder, seal the opening,drill hole in stud for easy out and remove. If stubborn, sometimes it requires heating the area around the stud (heat lamp) then squirting the stud with something real cold just before you try to remove it. Course should be done by certified individual. Screwups are costly.--


Just saw where it is flush with the cyl base. in that case, pull the cyl just far enough ou to get a big vise grip on the stud and try that first. Doing it without pulling the cyl will probably result in be catastorphe, but I suppose there is always some new ingenious way to do things

Steve Pierce
11-19-2007, 01:00 PM
Look in the parts manual to see which side it comes out. I have a stud remover and the proper collets if you need to borrow it. I would pull the cylinder if it were me. Had a R975 that never leaked oil after overhaul. Found out why. The overhauler used RTV on the cylinder bases and almost half of the studs were broken and being held in place by safety wire. :x

11-19-2007, 09:42 PM
I have a stud remover and the proper collets if you need to borrow it. . :x

One on ebay right now. Kinda spendy.

11-19-2007, 10:01 PM
I have used a UTP 65 rod on a stick machine to get broken studs out of cast iron or metal. I know it won't work on aluminum, but they are great on most twisted studs even if they are broken down below the threads. You just put the rod in the hole and start an arc and fill the hole with weld out to the top. The flux will run to the sides and protect the threads from the molten metal of the rod. The metal of the weld is very high tensile strength. I usually weld a nut, or flat washer and then a nut to the chipped weld for removing the stud. I have done this on tractor heads and blocks that cost mucho dinero. Just a neat tip that works well and worth passing on. David

11-19-2007, 10:27 PM
Just pull the cylinder and see what you have to work with. You wont get a new stud back in with the cylinder on anyway and you may find something else going on.


11-20-2007, 04:19 AM
Well I pulled it apart last night to find 2 Loose nuts besides the broken stud, so yes I'll have to pull the cylinder.[/b]

Steve Pierce
11-20-2007, 07:15 AM
I'd go through and check all four cylinders and look for signs of fretting at the case halves.