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Removing accessory case studs

stringfellow

stringfellow

Active Member
I've stripped the vacuum pump from the accessory case of my 540, and plan to just cover the pad. The studs are ridiculously long, like 3". I'd like to remove them and just use bolts to hold a cover on.

What's the best way to remove a stud? Double nut? Should I use any penetrant like Kroil or anything? Put it in the freezer for a half hour?

Thanks.
 
Try a double nut first.

Try a double nut first. If that fails and you don't care to damage the studs you can use a vice grip.
 
If room for it double high nuts will give you a better purchase. Or...buy a set of stud removers. Nice tools are like good friends!
Tim Andres
 
Update: I got all the studs out of the case. Yee haw!

I used the Bernzowrench (AKA propane torch) on the case area around the stud on a tip from a friend and it made all the difference. The 1/4" vac pump pad studs were the hardest. The 1/4-20 nuts I pulled off were quite soft and ended up spinning during double-nutting, but with with zero damage to the stud, proving quite a hardness disparity. I swapped in some grade 5 1/4-20 nuts and got enough purchase to pull the final and most argumentative stud.

The 5/16" magneto pad studs were very easy by comparison.

Off to inspection and paint prep...
 
spacers

You can also just cut four spacers out of tubing and leave the studs there so they can be used at a later date if needed. But yes, Blue point- Snap-on and others make nice stud removers that work if the old double nut trick dose not work for you. I left mine in and made spacers, then put a couple of Adel clamps at the end "under the nuts" for wires and tubing. If I wish to put a B&C generator there at some point the studs are ready to go.
Hope this helps, Yours, R.E.A. III #80888
 
stuck vacuum pump studs

Trying to remove my vacuum pump studs as per stringfellow above, but only got one of three so far. What am i actually doing here? Should I be heating the case only for more clearance, or should i be heating the bolt also to release some chemical bond applied by Lycoming? I can't believe these things are so tight. If I can get them out it will really help on installing my oil pressure switch, plus a slight weight reduction.
 
Your heating the al. case to hopefully get some expansion. The stud if heated will expand more than the al., so avoid that.
Tim Andres
 
Heat the case, keep the stud as cool as possibe, use penetrant, triple nut AND use vice grips -

Works every time!
 
Just reread your post and picked up the oil pressure switch comment. Maybe you know but just in case I’d suggest you do some research. Generally sensors like that are not mounted directly to the engine. Best practice is to remote mount them so they are not subject to engine vibration, which can cause the pipe thread fitting to break. Seen it happen....
Tim Andres
 
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