I knew the first 2 were too easy.... This one on the top, back side is a pain in the back side. I dont have a lift and am sure its a matter of leverage. First try had a slip and made me wonder about size. Why the bleep would they use 2 different size nuts on the same assembly?? Top are both 14mm and bottom is 13mm.
More penetrating oil and a dinner break., will hopefully help. I'll upload some pictures of this catastrophic mess once im done.
Got that last one. This time impact did the job, after trying a breaker bar and failing. About 10 seconds and the nut pulled right off. Again., patience, technique, and tenacity for the win! Next up., mid pipe joint, which i have done within the last year or so when i replaced resonator and muffler. Hopefully less painless and time consuming than cat nuts. May get that patch on trans case today yet.

 

Good luck!

 

Nice work. I gave up trying to get mine off myself and paid somebody to install my hfcs. Everything was so damn stuck. They didn't budge with penetrant or getting them red hot. I couldn't believe it. I'm baffled by all the stories that people have where they just come right off. My stories are like rod's but usually worse. I get half of it off and can't get the rest or something else breaks and then I don't want to drive it to a garage with half my exhaust off. So I bail out now at the first sign of trouble and pay somebody else (and feel like a failure).

Like I was just de-rusting the inside of an old motorcycle tank with acid and in 10 minutes the thing was pristine but now the lock cylinder is welded shut and I can't get my only key out of it. So my simple little project is now a multi-day adventure that includes me figuring out how to break into the lock.....

 

Thanks.
Luckily I have another vehicle to drive and can take my time. If I didn't it would be another story. Speaking of, I thought the nuts came off fairly easy. Just took the right technique and some patience.

So now the cat support bolt is the dilemma. I sprayed it several times with penetrant, but it hasn't budged and the bolt is damn near stripped. Out comes the 3" cut off wheel and a burr bit. I will drill out the stud and just use a bolt and nut to reattach.
same thing as with my muffler mount when the stud twisted clean off.
Where there is a will, there's a way.
I'm thinking i may not need to separate cat and midpipe flange since there is the flexible connection. Once the support is free, I should be able to lower cat out of way and get drive shaft out.
We will see. It sounds good to hear me say it, but usually entails some sort of complication, like everything else.
Again, patience, time, and technique. This is fairly routine problems, compared is needed in my job. Then I come home and do some more. Lol.

 

Although uncommon, make sure you always put lock lubricant or graphite in your sliding parts. Every used bike I buy had a sticky gas cap until I lubed it up. Spray WD-40 for now.

 

All these horror stories make me smile. Since I do most of the repairs on our cars, mowers, trimmers etc. I have plenty of similar stories. Living in the South makes it a lot easier to be a DIYer, I don't envy anyone who lives where it snows often. The running joke at our house is if I didn't bleed at some point in a repair I wasn't doing it right lol.

 

Wear gloves and working sleeves bro! Crazy.

 

And take all the fun out of the process, nah lol. I don't like wearing gloves for most of the work I do on the cars, I'm old school (and old) and have more flexibility and feel w/o them. And it's way too damn hot here in the summer to be wearing any kind of long sleeves, most of the bleeding is from small cuts and/or scrapes anyway.

 

Which would be fixed by a pair of elbow to glove protector sleeves and gloves lmao.

 

Uhg. Driveshaft slop ended up gougong a section of casing. Fortunately it doesnt appear any internals were damaged.
The notorious 3 cat to header bolts. 2 ft of extension and some ingenuity is required.
The real pita. The cat support is one piece and lower one side it reqires you take this completely off to drop driveshaft.
A 3" cut off wheel and 1/2" carbide burr bit removed the cat stud mounting to support bracket. The nut was rusted out and rounded on the first attempt to remove. I'll drill out the bracket and just use standard hardware to rescue, once the case is patched and new drive shaft installed along with the new cv joint.
Not expensive, but time consuming. $150 in parts.
wonder what a garage would charge for all this??

 

I was able to remove driveshaft without completely removing support in that last photo. After having to cut off studs from cat to y pipe, the cat droppped out with very little persuasion. Next, i removed the 2 support clips on 3/8" tube and was able to carefully move the tube in a way to get the driveshaft out. Next up, repairing the case damage. The header to cat gasket is in reusable shape, but i will have to replace the cat to y-pipe gasket and drill out/grind out, the studs on the cat. Hopefully be able to have this back together next weekend. While i have the cat out, i was thinking of making a fixture, in the event i need to replace the Cats in the future. I dont think i mentioned I am ASME Sect. IX P5 certified and have a 255a tig welder.
The entire exhaust system was definitely engineered for ease of original install and took very little in consideration, in the way of future repairs or replacement. Standard hardware and non-studded flanges would have been preferable.

 

I have a 03 and I'm changing out my y pipe versus my old one rusted through but I dont know what size the nuts are on the cats flange please help

 

I think they were 14mm, it was either 12 or 14. It will be pretty obvious when you're down there.