Cat back exhaust flange. Are they bolts or studs?

I am looking at getting a cat back replacement for my 04 trd. The flange after the cats is so rusted that i cant tell if it had nuts and bolts holding it together or if it was studs and nuts. All i see is rusted nubs. I cant even see nuts at this point.

Ill have to cut them to get them apart. I dont want to cut the studs if they are studs. Bolts.....who cares. Easy to replace....but if they are studs, i will likely have to drill them out or something to get the new cat back to fit.

I am not sure what the best thing to do is if they are actual studs.

 

Mine has bolts

 

ill have to get under there to see if i can tell for sure. If it is bolts.......i can cut them with my angle grinder and replace them quite easily. Its so bad with rust on the coupler that its anyones guess by looking at it.

 

can anyone confirm that 90917-06057 is the correct part for the flange from teh cat back? The diagrams look weird but its all i could find for a 2004 3.4l.

 

that's the gasket that goes in between the flanges. the flanges are welded onto the actual pipe. when I got a new muffler I just hacked off the pipe near the muffler and replaced with a Walker QuietFlow and used a band clamp.

 

hehehe.....im betting mine are worse but .....i can grind/punch them out, or cut them, or torch them. As long as they are bolts.

 

so they are not bolts then. THey are studs. no wrench will go on these. They are completely rusted and dont even have a hex shape any longer.

 

interesting....so they used bolts.....tightend them down and then welded them on? Odd. Yeah...there is no way these are comming off with any type of socket or impact. No bite anywhere. That probably wont stop me from going out and getting a new impact though. Ive wanted a new one for a long time.

 

Thanks man

 

Lol

 

Thanks!

 

You can still trim nut off and just use a bolt and nut. Use a Stainless steel one.

 

Thats the plan. I figure a grade 8 or 10 SS with lock washers. I saw another thread stating these were 3/8 or 3/8 fit for this. IM not using crappy bolts. I dont need this mess again.

 

3/8 will work

 

mine look like rusty pins, there is no semblance of nut/bolt anymore. thanks to salty winters and 13 years

 

Same here. Nightmare. Every time i go to do front brakes i have the same problem. Those stupid guide pins that are made out of equal parts of butter and pudding will not budge. Rust grabs them and its over. Trying to pound them out and the mushroom. Stupid design.

 

I use a punch and hammer. I wire wheel them and use a little oil or grease when put back in to fend off rust/sticking. haven't had any real issues in the 4-5 sets I've replaced.

 

im trying a bit of anti-seize this time around. I give them a tap every time i rotate my tires as well to try and keep them loose. Time will tell. The heating and cooling + the salt screws me each time. One battle at a time.

 

Yes 3/8 is what i used on mine i used ss but apply a bunch of neverseize if you ever want to get them off easy in the future

 

Took me about 30 minutes and i got my old cat back out in 1 piece. It was rusted so bad i couldnt use a socket.

The way to go was to take the angle grinder and cut the heads off the bolts that face the rear of the truck. I figure that way if i hit the flange , it would be on the side im replacing. ONce they are flush with the flange....give it a wiggle and it will come loose from the front flange. Next...take a punch and stick it on the flush part of the bolt head and give a couple of good whacks. They came right out. No drilling or other nonsense. Way way easier than it looked.

At this point, remove the rear hanger rubbers. it will be suspended by the 2 rubbers that hold the muffler. I got under there, gave the rubbers and post a good squirt of wd40 using a screw driver to wedge in there so the fluid would get in there. Lay with your head facing the rear of the truck and work off the rubber hangers with your hands. Once nice thing is you can put your feet on both side of the flange and push like hell to help get some force to help things along. It will land on your chest so be careful.....and your neighbors will look at you kind of funny wondering why you are under your truck banging your exaust .......Worked great. Then i snaked the exhaust over the rear axle towards the front.

Thanks for the help everyone. Now to get the new one on there. I hope i have everything. New gaskets, cat back kit, bolts. Not much too it. Muffler bearings look good. Ill probably reuse those.