036mtmax

iTrader: (11)

Going to drop my precat tomorrow can anyone give me the most straight forward way to get it off.I gutted the rear already and that was a b**** just a temp fix before header install.Thanks in advance for any help.

nelledge

iTrader: (6)

Spray all the fasteners tonight with PB Blaster and let soak. Take the front heat shield off for access(3x10mm). I believe two of the six fasteners(12mm) must be removed from above. Remove the downstream O2 sensors. Drop the y-pipe next: heat-shield nuts(10mm), two nuts to the rear cat(14mm), 3 nuts to the rear pre-cat(14mm), one hanger bolt(12mm), two support bolts(12mm), 3 nuts to the front pre-cat(14mm). You'll then have a clear shot to the remaining four fasteners on the front pre-cat(12mm). Be patient. It'll be a bear to get to if you round off any of the heads holding the pre-cat to the manifold. If that were to happen, just pull the pre-cat with the front manifold as an assembly. It's a little more work, but will probably save you loads of time in the long run.


PS: Use the PB Blaster early and often when removing exhaust or under-carriage. It's your best friend. Especially if you live in road salt areas.

Eirik

iTrader: (2)

Don't forget that the best technique for loosening those 8-year-old bolts is to actually tighten them a squidge before you try loosening them. The bolt will move just enough to shake off the last of the corrosion that PB Blaster won't be able to completely eat through. For some reason, just trying to un-tighten instead leads to the bolt resisting all motion and rounding off the head.

Read about that trick on Popular Mechanic's website a few months ago and haven't rounded off or stripped a single bolt since.

036mtmax

iTrader: (11)

thanks guys ill let you know how it goes

foodmanry

iTrader: (15)

My dad showed me this when I was a kid....it works for any nut or bolt regardless of rust. Not sure why...but it works so I'm sticking to it.

TallTom

cmax1

can these bolts be reached with a impact gun with maybe a extension on it? would this method make it easy to remove?

036mtmax

iTrader: (11)

yes i got at the top and bottom bolts with an impact but i heated every bolt with a torch before cracking em loose first and if you do that you probably wont need an impact,it was a little easier since i left all the heat shields off the y the last time i dropped and gutted the rear cat.

cmax1

what are you using to keep the check engine light off? and how did you remove the insides of the cat? were you able to remove all of the honeycomb?

NAVY00MAXIMA

I religously use a wire brush on ALL of the threads, nuts and washers when it comes to the exhaust to remove the worst of the rust before using penetrating sprays such as WD40 or PB Blaster.

Rods03Max619

iTrader: (5)

When you get it off a long screwdriver or a prybar should be able to knock it all out I used a pry bar for the front...and some get a CEL and some don't but those who do use the 02 stimulator....

NmexMAX

iTrader: (22)

My secondary O2 sensors haven't set off a cat code even though I've been header'd and cat-less for a very long time.

036mtmax

iTrader: (11)

Punching the rear cat was a horrible experience.The inside mesh inside the cat is pretty bulletproof.I squeezed the cat in a bench vise and used an air chisel with a long bit and chiseled my *** off for about a half hour and the front cat pretty much fell apart with a few whacks with a pry bar and a small sledge. And my cel is on but i just got inspected in march and i need some more info on sims or an alternative.It sounds pretty nasty now with the test pipe and the cattman cat back.

NmexMAX

iTrader: (22)

Plug your secondaries in and either add a port for them, or let them dangle (zip tie them) in the engine bay as long as your primaries are plugged in where they should be, you'll be fine.