As implied by the title, I'm kind of struggling with a couple of these spring bolts.
Car in question is an Acura RSX, it uses these bolts between the exhaust manifold and the front end of the cat:
The left side bolt is even harder to access.The flange is tucked way up inside the subframe, so it's difficult to get anything in there to help compress the springs. I don't have the strength to compress them directly with one hand while getting the nut on the far side. My pseudo-domesticated gorilla son is gone for the weekend.
Ive tried various channel locks, a couple vice grips, and a ball joint tool, but no joy. The ball joint tool seemed to work best, but getting even a stubby 19mm wrench in there is challenging.
I was hoping to have it back together tonight , but gave up partly out of frustration, partly because my back can only tolerate so much crawling around under the car.
Anyone have any thoughts or suggestions? I feel like it shouldn't be hard and I'm missing something obvious.
Is this an aftermarket exhaust? On my S2000 the thread reaches the other side without any force.
There is like a step on the bolt correct? That goes through the flange I believe.
I wonder if you are installing it correctly. I need to do some research to remember exactly how they assemble, but it was never a problem for me.
Ok, I remember now.
The little shoulder goes through and bottoms out. See picture below. One time I was having a hard time getting it assembled and it was that little shoulder, I had not realized it went through the flange.
Another option is to find a longer bolt/nut and use that to bring them together and start on the other side.
I've had situations where I was using new hardware and I had to squeeze the new springs a few times in my bench vise to help them take a set and be a bit shorter.
It's a stock replacement cat. I know what you're talking about with the shoulders; I did a center section change on my daughter's 8th gen Civic a few weeks ago and those bolts had shoulders and were a simple change.
These don't have the shoulders 
The manifold flange is pretty thick, about the thickness of a nut, so the spring needs to be pretty compressed to get the bolt thru the manifold so you can get the nut on it. The new gasket is the same thickness as the original, its a tapered style that kind of acts like a ball joint and serves as the flex joint between manifold and cat.
I do feel like Im missing something simple here.
Any chance you can compress the spring in a vice and use a heavy duty zip tie (maybe metal) or wire to keep it compressed while installing the bolt?
Its a run to home depot away from being installed!.
Get some 4" or 5" long bolts and use that to get them closer together.
Try Cousin_Eddie's suggestion also if you have a vise.
You got this!
Thanks for the suggestions! I figured I'd check out the manual, and it appears that the holes were originally threaded, but apparently my dad drilled them out in the past. 
Two interesting things here: Slippery, if you look at the drawing, it originally used the shouldered bolts. Second, according to the reciept left in the shop manual, he bought the new bolts and gasket on my son's 10th birthday .
Of course he doesn't remember any of this or how he managed to start the new bolts 🤦♂️. Getting old sucks.
I guess I'll try a bunch of zip ties and crank it down in the vise.
Here's current status: same as Friday...ended up taking a day of rest from crawling around under the car.
I did a somewhat sketchy press operation to compress a spring all the way:
Then I happened to find the old springs on the floor after still being able to get a bolt into place.
So it appears that the new springs have another full coil. When I was trying to get the compressed spring into place, it occurred to me that if I did get it to bolt up, the spring would be fully compressed if I were ever to get a nut on the other end.
Swing the exhaust one way, start a bolt, swing the exhaust the other way, start the other bolt.
Edit: Nut? The manifold should be threaded. New spring bolt kits usually come with nuts because they assume that you destroyed the threads in the manifold.
Looking at your old parts, I'd just use the old stuff. It looks pristine, or at least plenty good to reuse.
OK I yield 
.
I feel like Pedro at the beginning of Napoleon Dynamite "This isn't that complex..."
I tried compressing down the old spring, but even with the human forklift cranking it with both hands trying to pick up the front of the car thru a 3/8 drive ratchet, there was no way to get enough threads to engage a nut. No way would I be able to get two nuts on there to lock it down. Even with the shorter old springs, they would be completely coil bound.
This is a Magnaflow allegedly stock replacement cat. When it's clamped up to the manifold there's about a 1/4" gap, which doesnt seem abnormal. I'm guessing something about how the flange and pipe are shaped it slightly different than stock?
Guess I'll stop at the FLAPS and hope they have something similar but longer.
Pete, yes you're correct, the threads were drilled out.
Just realized I never updated this with the solution. I ended up going to McMaster Carr's stainless hardware section and rolled my own:
There's plenty of room up behind the manifold flange, so I decided to get bolts with extra length since I didn't have anything suitable in my bolt bin. I got some spacers to fit inside the spring and act like the shoulder on the original bolts.
I also ended up making new heatshields since they were pretty well rotted, especially the rear one. The front one over the cat was still intact on the sides and most of the mounting holes, so I bent up a piece and riveted it to the original.
The heatshield stuff was like $25 for a 15x39 piece.
Good job on the spacers. Need to have something for the bolt to tighten against besides the spring.
Where did you get the heat shielding from?
Call me next time you need help!
Pete the heat shield was from the jungle site: Peastorm Exhaust Heat Shield Automotive Embossed Aluminum Heat Shield Muffler Exhaust Wrap, 15" x 39" https://a.co/d/8l0bHHU
Yes, my inner 12 y/o finds Peastorm to be humorous....
I also got a smaller one for the front shield.
Pat I thought you were uo at the cabin while this was going on, or I would have done phone-a-friend...
