Taking off the hitch every winter, will it damage the bolt hole?

There's myriad automotive products too, that go on liquid, then gel, form a film. not sure how they'd compare to linseed oil. I've coated an outdoor cedar table with linseed, I think that sort of thing is it's traditional application. But who knows.

Here's one commercial example, I haven't tried it though:

 

@tvpierce I had some boiled linseed oil, and a foam brush, so I did the rear axle, trailing arms and sundry yesterday. Took the plastic covers off, the ones that cover the traling arm links, also the rear wheels. Also loosened a few of parking brake cable brackets for access. Had it jacked up and on safety stands, took a couple of hours. Checked it today it's tacking up pretty good, looks nice and shiney.

 

I've used a foam brush before too -- simply because that's all I had. It worked OK, but a conventional brush seems to get in crevasses better.
Boiled linseed oil is an old farmer trick. Was used to protect farm implements and such. I'm told it's the prominent ingredient in rust protection services -- like Ziebart.

 

The linseed coating ends up slightly golden, I think. Most of what I costed was black painted.

 

This is 4~5 days post application, it looks wet but isn't. Not tacky feeling.

 

If you ever need to do those back hub assemblies, you’ll be in for a treat.

Have the rust penetrating solution at the ready.

 

IMHO (in my humble opinion), you're losing an awful lot of sleep over nothing.

Loctite is sort of akin to putting a very thin layer of latex paint on the threads. It will keep the pieces from coming apart by themselves, but still allow you to snap them apart with hand tools, breaking a light seal.

You're worried if these metal pieces will wear out. Yes, they will. In about 100 years. Unless you have some really extreme conditions (a lot more than just a little salt and snow) you might be better off just finding some replacement bolts and throwing them in the glovebox, just in case you ever need it, and for your peace of mind.

I really like Maurice's idea of just leaving the bolts in the holes year-round. You can't really wear out metal bolts during your lifetime by taking them apart twice a year. In fact, taking them apart twice a year is what will make them last even longer, since they'll never have a chance to seize up.

 

Work safe, always use jack stands. I like also an "insurance policy": a tree stump section, about 13" diameter and about the same length: I just push it under there first. It's thicker than me.

 

Looks good.

 

It's for locking bolts in place so they don't come loose.

SM-G920V ?

 

If you use a thread lock like Loctite you want the threads clean and dry, no oil. If you choose to just lubricate the threads no Loctite.

Like was mentioned, use the blue not the red. The red is permanent.