cats coming apart, need input

**hourang** · 05-26-2011, 01:15 PM

so my cats came apart and are rattling in the exhaust. i was quoted over $800 to replace the ypipe

dealer wants $750 plus for just the part, ebay has aftermarket ones for $400+. i would love to just gut the things or replace with straight pipe. everyone seems to get their tree hugging panties up in a bunch for even thinking of the idea. anyone know a place that will gut the cats for me? prefer somewhere in oakland county mi. they also quoted me $380 just to replace one (not sure if both are bad). i would prefer to gut it as something else caused the problem (i think it was the bad fpr i replaced) and im not sure if the new cat would just go too and waste all my money. or has anyone done this themselves? do i just unbolt the ypipe and use a crowbar to break it all up? i have a welder but im new to this, not sure if i would trust myself or be able to put a straight pipe in. im not even sure if i can access the cat without cutting the pipe. other option is possibly buying an aftermarket universal cat and having a shop put that in but some shops will only do oe style cats.

**Tweaks** · 05-26-2011, 01:40 PM

If it were me, I'd shop for the Magnaflow stainless steel direct replacement y-pipe that comes with high-flow cats already in it. You will need some extensions to reach the bolts to the manifold when you attack them from below, but aside from a few bolts maybe putting up a bit of a fight, this is an afternoon in the driveway sort of fix for a do-it-yourselfer.

If you want to save even more, you can ask folks who are putting LT headers on their 4.8/5.3 if they wouldn't mind selling you their now no longer needed y-pipe. I know the quotes for cat replacement is seldom cheap and the shops use a guide that tells them how many hours of labor to bill, so that jacks the price up, but in reality it is an easy job and better parts can be bought online and for cheaper than what the shop will bill you for them.

**hourang** · 05-26-2011, 02:00 PM

Originally Posted by Tweaks

If it were me, I'd shop for the Magnaflow stainless steel direct replacement y-pipe that comes with high-flow cats already in it. You will need some extensions to reach the bolts to the manifold when you attack them from below, but aside from a few bolts maybe putting up a bit of a fight, this is an afternoon in the driveway sort of fix for a do-it-yourselfer.

If you want to save even more, you can ask folks who are putting LT headers on their 4.8/5.3 if they wouldn't mind selling you their now no longer needed y-pipe. I know the quotes for cat replacement is seldom cheap and the shops use a guide that tells them how many hours of labor to bill, so that jacks the price up, but in reality it is an easy job and better parts can be bought online and for cheaper than what the shop will bill you for them.

yeah its $400+ for the magnaflow. at least the quick search that i did.

that would be awesome if someone had a good used one (or even one with bad cats that would be easier for me to gut and can do it while im still driving my DD. if anyone has anything local pm me.

would i need new gaskets or bolts for the ypipe? 130k miles on this truck in wonderful michigan rust zone.

**BHB** · 05-26-2011, 02:14 PM

I've done that. take it off, break it up with a long prybar, and shake it out.

**dagen_1** · 05-26-2011, 02:27 PM

Originally Posted by BHB

I've done that. take it off, break it up with a long prybar, and shake it out.

it works... been there, done that!

**hourang** · 05-26-2011, 02:33 PM

Originally Posted by BHB

I've done that. take it off, break it up with a long prybar, and shake it out.

was this on an NBS with 2 cats? im not sure with the bends if i can reach the cats or not. did you need new bolts or gaskets? how long does it take? im leaving for up north tomorrow and if it dont take that long i may do it before i leave.

**Tweaks** · 05-27-2011, 07:08 AM

If you go that route, no need to take the y-pipe off in theory. You can simply remove the two nuts at the end of the y-pipe and the beginning of the intermediate pipe (just in front of the muffler). You may have to slip some of the exhaust out of their rubber hangers and that is pretty easy to do as this will allow you to move the exhaust out of your way and provide access to shoving something up into the y-pipe to reach the cats and break up the catalytic brick material. One of your cats is already separating so cleaning that one out will be a piece of cake. It doesn't take much force to break up the cats, but you will need to get creative and find something that can snake up in there, be long enough to reach the cats, and allow you to apply some sort of jamming force to poke at the cats and break them up. I would not start the engine once the cats are broken up. I would attempt to vacuum out the pieces to prevent the chance that some of the crap gets pulled back up to the engine upon start up.

This way, you won't have to fuss with gaskets or manifold bolts. I would, however, soak the end of the y-pipe threads and nuts with something to help loosen them up and I would also hit them with some heat from a little propane torch before loosening the nuts because the threads are welded to the y-pipe and they love to snap off from age and corrosion. If they snap, simple drill them out and replace them with good bolts, washers, and nuts... that's what I had to do to mine.

**hourang** · 05-31-2011, 09:07 AM

Originally Posted by Tweaks

If you go that route, no need to take the y-pipe off in theory. You can simply remove the two nuts at the end of the y-pipe and the beginning of the intermediate pipe (just in front of the muffler). You may have to slip some of the exhaust out of their rubber hangers and that is pretty easy to do as this will allow you to move the exhaust out of your way and provide access to shoving something up into the y-pipe to reach the cats and break up the catalytic brick material. One of your cats is already separating so cleaning that one out will be a piece of cake. It doesn't take much force to break up the cats, but you will need to get creative and find something that can snake up in there, be long enough to reach the cats, and allow you to apply some sort of jamming force to poke at the cats and break them up. I would not start the engine once the cats are broken up. I would attempt to vacuum out the pieces to prevent the chance that some of the crap gets pulled back up to the engine upon start up.

This way, you won't have to fuss with gaskets or manifold bolts. I would, however, soak the end of the y-pipe threads and nuts with something to help loosen them up and I would also hit them with some heat from a little propane torch before loosening the nuts because the threads are welded to the y-pipe and they love to snap off from age and corrosion. If they snap, simple drill them out and replace them with good bolts, washers, and nuts... that's what I had to do to mine.

thanks for your response. i really cant think of anything i could use that could snake up there and knock it out. i think ill just buy new gaskets and bolts anyways. then when i get the funds for long tubes it will just be that much easier to drop the exhaust. i wish i could find a shop to do this for me, i used to have a place but i cant find the contact info for it and i do not remember how to get there as it was hidden in the back of a subdivision and i only went there once.