Which tool 2 use on this bolt for replacing shock absorbers?

You can try to heat and quench it a few times. Otherwise have it cut out, then replace with nylock nuts. If the nylock nut seizes it’s easier to get off with a little MAP gas.

 

Do you have a pic of the tool they use?

 

I would be tempted to weld the nut to the frame to stop it from spinning. Just be careful not to sit in one place too long or the threads will warp or fuse together.

 

Socket on a breaker bar or ratchet?

Open end of the wrench?

 

I have many modified wrenches. You can see a gap, but your wrench is too thick to go in. Go to Harbor Freight or find the cheapest wrench in your drawer. Go buy a better wrench if you destroy your only one. Make sure its a 12 point. Take the grinder to the outside edge of the wrench until it fits.

If the angle is the issue heat the wrench and bend to fit.

Can you get a pipe wrench on it from the end?

 

My trailers the same way. And rusted. I’ll pay a shop to cut them off. When it comes to changing shocks, Shops usually cut the shock in 2 spots, get it off the bolt, then cut bolt off. Best way. I don’t know if you have acess to the other side or not. If so, try jamming a pry bar, crow bar, or big screwdriver to hold the nut, turn the bolt. Unless it’s a stationary post. IDK.

 

That’s a metal lock nut. They must’ve used a thin socket when they did the install.

When I do shocks or something that’s in a difficult place, the torch becomes my favorite tool.

It’s so much quicker to cut off the old bolt and put in a new one.

Usually the old bolt will be at the point it’s become too rusted and weak to bother with reusing.

Also once the old bolt is out, the new bolt will likely be in a better position to allow a wrench to finally fit.

 

Honestly at the trailer shop the tool they use is probably a torch. Most likely they torch that off.

It's hard to tell how much room you have there but if you had a wheel cutter or an angle cutter maybe you could cut the bolt and cut the nut vertically. Even if you only cut one side of it or maybe if you could cut a small X then you could probably take a chisel and knock the nut off.

I can't see how the top of the bolt mounts in there but maybe would be easier to cut the top part. If you cut that into an X without cutting the frame itself you could probably take a chisel and break the head off and knock the bolt through. You could probably drill through the head of it and if you had the right size drill once you get down to the stem the head will come off but who wants to do all that Drilling? And it looks like you would need a pretty good-sized bit for that also.

These situations though most people just use a torch.

I don't know how much room if any you have on the other side but if you had a welder and you could clean that nut up a little bit you could probably weld a smaller nut on to it if you could grab it with a good weld and then you'd have plenty of room to get a socket on it and zip the top out.

@Goodysnap has the right idea though. Take a wrench and grind it down or even take a socket and grind it down to fit up in there. Sometimes something like that is easier to hold with a socket and a breaker bar than a wrench unless you can wedge the wrench against the frame itself.