Exhaust flange question

I need a new exhaust from the cat back, probably just going to go with OEM replacement. My question is about the flange where the mid pipe bolts up. Is that flange threaded and/or have welded on nuts? Or just regular nuts? Mine is pretty rusty so it's hard to tell. The bolt and spring kits don't come with nuts so I assume the flange is threaded?? If so, mine may be too far gone. I guess I could drill it out, cut off any remnants of welded on nuts and use new loose nuts. Anyone know the specs for these bolts? Maybe M6 or M8? Other than the hardware and the hole in my muffler the rest of the exhaust doesn't look too bad.

I'd appreciate it if someone here with a Cali or AZ desert truck could post a photo of what this is supposed to look like.

 

Not looking for a picture of the exhaust, just the detail of the mid pipe bolted up to the flange on a truck that is clean and shiny... where the red arrow is pointing in my photo above.

 

Here's a diagram that might be helpful. Looks like it's 2 bolts, 2 springs and a gasket. No nuts. Not sure what thread pitch, but you're likely gonna be cutting anyway so if you're not using new Toyota hardware, use whatever nut and bolt setup you like!

 

The backing nuts are welded to the flange. Remove the 2 bolts

 

Yep. I'd say a 50/50 shot of those bolts breaking....resulting in having to drill out the nuts. If that happens....gonna have to tap and rethread the nuts or cut them off and start fresh with some new nuts and bolts

 

Although I had Toyota replace my catback with a TRD unit, I had them order new hardware because mine looked much like yours. Glad I did because they needed them.....

 

Aftermarket exhaust + urd y-pipe. CA truck

 

That's what I thought and that's what I was afraid of. I'm sure I can get the bolts out one way or another even if I have to cut them and drill them. But I am not holding a lot of hope that the threads on the flange will be salvageable. It wouldn't be too hard to clean them up with a tap but they may just be too far gone rusty for that. The bolts and springs are readily available and cheap. And it would be easy enough find some nuts, but it won't be quite as solid a connection without welding them in. But those y-pipes are $$$... yikes.

My other flanges and the exhaust manifold bolts all look as bad as these. I don't want to get into a situation now where I just keep chasing this back to the motor and having to replace all of it. Too $$$ and I just don't have the time to put my DD Tacoma out of service for the time it would take to do that job in the winter. And the pipes themselves are fine. It's just the hardware and probably the flange threads. I guess we'll see how bad they are when I get into this. For now I wrapped the muffler with metal HVAC tape. Not a bad temporary repair.

Really liking SUMOTNK's URD y-pipe. That is a seriously thick flange. Probably a forever part.

 

Hack that mess off. You can get a replacement spherical joint kit for like $20 bux.

 

The nuts are only welded on to allow for easier bolt up at the factory. They don't have to be

 

That would work... if only I had a welder.

 

My bolts looked the same when I did my muffler. I heated them with a torch and got the bolts out. I grabbed the remains of the welded on nuts with vice grips and broke them off. Cleaned up the flange a little and used new nuts on the back.

 

I put a Walker Quiet Flow from Advance on and an intermediate pipe and the Walker spring and bolt kit required me to buy nuts believe bolts M10x1.25.
Cut the old stuff off bolts and nuts and you are good to go.
One problem area was the flange donut from Walker seemed a tad too small so had a sealing problem but that was the correct listing so I reused the old one and it worked. If you have dealer access buy an OEM donut and save yourself the extra work and dealer also has a better spring/bolt kit.

 

Just pick up toyota bolt and spring and pick up nut from hardware store . Toyota bolt looks long enough for regular nut . Better yet self locking nut but not the nylon lock nut . Need the spring loaded bolt cause needs some flex there or might crack develop cracks in exhaust system.

 

If you cut/grind the end of the bolt that protrudes through the nut flush with the nut, then use your penetrant of choice and let it sit a bit. Then heat the nuts with a torch, you should be able to remove the bolts without destroying the flange and nuts, even in their condition. But grinding the nuts off too and replacing with new wouldn’t be too bad. And new Toyota doughnuts work the best to stay leak free

Edit: after a second look at the pictures, those nuts may be too far gone