Precat removal (please don't flame)
 

For my 03 maxima I would like to remove and gut both precast the problem is my mechanic says they are rusted pretty good ,1st question does the whole y pipe have to be removed or the cats individually , if the bolts are rusted and have to broken off is there anyway to put it back on I'm really concerned that if he starts the process something will break and I will need to purchase new cats.also does anyone have any old precast of whole y pipe set up they are not using thank you org

the heat shields are a pain in the ballonieies

I didn't waste time, I just cut the bolts off my exhaust system and used new ones. To far rusted to even try.

Last weekend I was about to do the same (I.e. gut my precats, etc.) & finally found some headers which I plan on installing next weekend. I broke one bolt on my left (or front) precat. Where it connects to the manifold and ended up stopping just short of gutting and decided to reassemble and wait on headers to get here.

The back precat can be gutted while its still installed but the front has to come out.

You also need to figure out how you manage your ses light once your cats are gutted.

Thanks for the reply fellas maverick did you mean use new bolts or whole new exhuast ? And I have one anti fouler installed only took care of one code I can't get a non fouler on the other car for the second code , I plan on using a o2 sim for the other cat I think I was only able to get a non fouler on bank 2 I believe , did anyone break anything in the process ? Or is all I have to do is use new bolts to reinstall

No my exhaust is same. I plan on upgrading first of next year. I just cut the heads off te bolts in the bottom side for the main car and ypipe. Unbolted all the precats and dropped them out. I don't reccomend gutting them on the car

Ok thanks were they hard to remove due to rust ?

I put my max up on a lift yesterday to attempt gutting the cats on my 02. What a nightmare. I removed the fan shroud to gain access to the front. I was only able to remove one of the three (that I saw anyway) bolts on the heat shield. So from there I removed the blue o2 sensor and cut away as much of the shield as I could, just enough to gain access to the top 2 bolts of the precat. I also had to cut heat shields off underneath the car since those bolts were a rusted glob. From there, PB Blaster, propane torch, impact, and not a single bolt removed. No idea what to do from here, might just find a mechanic to do it for me. But I had two USAF mechanics with me yesterday and even they were stumped.

Front pre to ypipe
http://img6.imageshack.us/img6/175/3ajw.jpg

Rear pre to ypipe
http://img4.imageshack.us/img4/6691/0wxx.jpg

Thanks man really appreciate the pics this is what I'm afraid of not sure if to cough up the money for some obx headers(still cheaper than precat) or search for used y pipe from someone who has already installed headers

http://m.ebay.com/itm/261328292616?nav=SEARCH&sbk=1 is this correct ?

I tried this guy first. Got an initial response, but he's 3.5 hours away from me. Asked about shipping, never heard back. You can give him a shot, good luck.

https://maxima.org/showthread.php?p=8873507#post8873507

Thanks man

That's the front. Two bolts accessed on top, four from underneath (where it attaches to manifold). Swivel joint and a long extention needed for those four. Three bolts to the ypipe.

Oh ok if that's the case I might gut this myself and attemp to take of the existing one , I can get rid of the codes but I want to do this ASAP before I hurt the car

Non foulers will remove the codes. I picked up two sets, drilled and ready to go. But I can't get them darn bolts free. No idea what to do from here. Talked to one mechanic so far (friend of family) and he just lectured me about smog and said he won't help. But he has no problem getting me two new precats and installing them for $800 :-/ I have one more guy I'm going to try around here then I'm done.

Here's a shot of the non-foulers
http://img855.imageshack.us/img855/5743/henr.jpg

This is one of the most frustrated things with the 3.5 I have a non fouler on one cat can't get it on the second I plan on using an o2 sim I wish someone would make aftermarket gutted precats for us

I'm curious to what size bolts you used to replace the ones you cut. Just so I can buy them ahead of time. From what I could see (which wasn't much) it seemed the cats themselves were treaded for the bolt, is this true?

Lets see, I soaked all bolts in Kroil (best stuff ever) unbolted the precats from the car breaking a few bolts in the process. got it all down just used a zip wheel to cut the ypipe, main cat, and other exhaust items loose. Laid it all out on the floor and disassembled the whole thing. After that I media blasted and painted the whole thing in hightemp black. Drilled lager holes in the main cat and items like that and instead of using threaded holes I used nuts and bolt. Its was easier this way. just went with some nice stainless bolts and antisiezed it all. As far as the cars I drilled and re-tapped all the holes with one size up I think they were M6 cant remember with 12mm heads. Antisieze and reinstall whole system with new hangers. When spring comes around I will pull it all off and put my cattmman system on. As far as this goes I have had it off twice since I did the work and it was no issue removing it

Hmmm very interested so basically for the. Bolts that broke you just fab something in order to bolt everything up correct ? And you removed the whole y pipe instead of each cat ?

It wasnt that I broke it and just made something up, the nuts are welded to the other side and a bolt threads in. I just snapped that off drilled it out and got new. Works way better this way and it will never rust. I dropped everything from precats to muffler

Thanks for the info Maverick. Going to get it on the lift again possibly next weekend. Maybe use something stronger than a propane torch this time.

I never used a torch, Im telling you Kroil is your friend. Soaked for 10 min all my rusty bolts came off easily. Its the weak POS heads on thos bolts that your gonna twist off. My precats all twisted off. After that screw it I just rebuilt the whole system. Let me know how it goes

who ever posted those non foulers be sure you drill them out or the CEL will still pop up.

Those are my non-foulers and I did drill out the one the o2 goes in. Drilled into non drilled, then into exhaust stream. That's how I've done it before on other cars, did I miss something here?

sorry holmes, the pic is large on my ipad and I only saw the one that was still closed up, after reviewing on PC I se what you did. My aplogies

All good, made me second guess myself for a sec. Lol

i suggest to unbolt the bank2 (front of the car) and gutt it and put it back on... for the bank 1 in the y-pipe... for me i cut a bigg hole in the precat (outside) to get access the ''honeycomb'' and welded back the parts that i cut :P

WARNING this is not a ceramic one like the front its a super tough mettalic
http://s21.postimg.org/b46hxp707/WP_20131203_002_1.jpg

if you think to gutt it with a flat head screwdriver like the bank2 you will start crying hahahaha i take a huge makita drill with a 1'' drill bit i make 3-4 holes in it and after i pryed it a lil bit and it came off

and for the antifouler... i never had to buy some... p0420,p0430 came on for sure and after 1 month of driving, the carbon clogged the oxygen sensor and i cleared my SES light with a scan tools 2 weeks ago and still no SES light.

Am I supposed to drill out all 4? Also what size did you use or should i just have them completely open?

They are 18mm. Drill out one per pair, then assemble as such: o2 into drilled, drilled into non-drilled, non-drilled into the port on the pipe.