ok, as always I did a search before hand and couldnt find what Im looking for
Does anyone have a tip on how to remove the main cat? I tried to use a socket and it just wont turn (even with PB). This is one of the last pieces I need to do to get my car back on the road after my single conversion... any hints or tips would be very helpful
Neal

 

More pb + breaker bar. Jack the car all the way up so the breaker will clear.

 

Soak in PB overnight, soak some more. Use a 2lb dead-blow mallet on the breaker bar. It can really suck.

Dave

 

Just use lots of PB blaster and anything you can utilize to get more leverage.

As dgeesaman mentioned, the BFH approach can work too.

 

If all that doesn't work, get a "nut cracker". It fits over the nut and will split it in two. Or a cutting torch or grinder. Replace the hardware with stainless stuff. Use nickel antiseise on the bolts when you reinstall.

 

thanks for your help.. would removing the heat shield help out at all with moving around? Right now the car is on jack stands and I only had one go at the cat before creating this thread.

 

If you don't plan to re-use it, I would do as David Beale suggests.

 

Just one note: the stock main cat uses an odd thread pitch - M12x1.25 or something like that. So if you crack off the nuts, the problem is you will need to get new ones from Mazda. If you try to unscrew the nut, it may shear off the stud. Then you have to get the stud piece out of the hole which can be very difficult (I took mine to a shop). You can't replace the stud, since Mazda doesn't sell them separately that I know of.

Not trying to make rain, but realize each method has potential difficulties.

The BFH approach is for good reason - using a breaker bar and mallet puts a shock into the assembly, just like an impact wrench. That shock IMO helps break stuff loose better than simply pulling hard on the breaker. It kinda helps if you put some pressure on the breaker bar while hitting with the hammer to take some of the bounce/flex out of the equation.

Dave

 

With bad rust it will take several days to a week of soaking daily with PB blaster (or similar) on both the nut and the stud. You will then need a good 3' breaker bar if you have the clearence or an impact wrench to break them loose. You could possibly have stripped studs also. In that case what Maverick said. You may want to replace the studs with new or some studs or bolts afterwards. Don't forget new gaskets.

 

This is the method I successfully used. Using a cheater pipe also helps.

One thing worth mentioning is the significant weight of the main cat. I used a jack when removing and reinstalling a new one just to make my life easier.

 

I had to use a more unfortunate approach..... 1/2 impact, grinder, 13 drill bits and bolt/nut.... not cool..... lol

 

It took me maybe 2 hours to get my exhaust manifold & dp-cat bolts off

It took me maybe 4 hours to get the damn cat-catback bolts off. Two bolts, 4 hours : / It was probably the best workout I got in a whille.

 

I busted the stud off one of the cars when I was removing the cat. The next car I decided to just go to the muffler shop and have them loosen them for me, drove home with the nuts loose.

As degeesaman says, the stud is very difficult to remove, I had to drill it out took mer about a half hour.

You can also try to heat the nut.

 

I just put a main cat on last week after my original one went to ****. We jacked the car in my parking lot and used Gunk Liquid Wrench, we soaked the **** out of the last two bolts and banged on them with a wrench. The directions say to tap on the place of contact to create vibration, thus loosening the nut. So I laid on the floor for a full 5mins just banging on it, then I took my wrench and went for it. Fortunately for me it got loose and did not strip, as we reused all the bolts. Hope this helps!! peace..

 

dremel is your answer if the breaker bar trick doesn't work. just cut the nut in half and you should be able to turn and pull the bolt out. like it said on top, don't plan to reuse it.

 

drive to a shop get it on a lift like books said
Just hand someone 20 bucks and tell them to switch out the cat with whatever you have