I can't for the life of me figure out how to get the precat off. I have 1 shop manual and two other books and none of them give any detail on how to do this.

I can't get the heat shield off the top part. I have removed the bolts but I can't slide it out. I can't get the 02 sensor off because I can't get a open end on it because it is to cramped. And to top it off the cat nuts have some kind of lock nut on them. Am I suppose to remove it from the bolt side or the nut side and if it is the nut side how do I get the two metals tabs that are locking it down off? The engine was just rebuilt so I can only image the guy that did the rebuild would have had to remove these nuts.

If I can't get the heat sheild out I can't get to the nuts that hold on the precat with a regular socket. It will have to be an open ended. Thanks in advance. This is really frustrating!

 

The "pre-cat" is commonly called "the exhaust manifold" and yes, those nuts can be a bitch.
Soak them with PB Blaster (or the penetrating lube of your choice) and they should come off eventually- assuming the studs don't just break.

 

The Pre Cat is NEVER called the exhaust manifold except by people that don't know WTF.

You have the top two nuts removed from the heat shield - but there is a 3rd bolt that can be seen best from under the car. It holds both heat shields to the exhaust manifold. You can then slide the heat shield to some extent.

As far as the O2 sensor - vise grips at the base only, perhaps a Mexican Metric Wrench (crescent), or an open ended wrench.

There are three nuts to remove and separate the exhaust from the turbo. I'd recommend a box wrench and an extension of your choice to break them. You will probably need to remove the bottom one from under the car.

The above are what you need to remove... I trust that you won't post back the all too common, "I tried and tried but it won't come loose (whine, cry)" post. It only gives the rest of the forum permission to call you a *****.

 

I wasn't referring to the part he is removing, rather the part which holds the studs he is trying to remove the nuts from- which I believe even Mazda calls the "exhaust manifold".
Yes?

 

You need better tools. Get an 02 sensor socket.

 

+1,000,000,000,000,000

get an offset 02 wrench and 3 feet of extensions and a 3 foot breaker bar, lol. its what i used and it was still tough.

 

chaosseven,

Thanks for the reply. I need a good set of box wrenches anyways so this is a good excuse. As far as getting one to fit around the nut, do I just use one that will go around the nut and those metal tabs coming off the washer under the nut? Sorry for sounding so "duh what do I do", but I have never had to deal with those tabs on any other nut on this car. Most of the work I have done is cat to mufflers and clutch work and never had to deal with these freakin things!

Thanks again!

 

no.

 

Take a look from the underside of the car where the pipe connects to the turbo - all will become clear.

 

Gotcha! That's one big gasket huh? Those tab things aren't even bent over on the bottom nut. Are they suppose to be bent over on the top two nuts? Thanks again for your help! One last question. I have searched all over my shop manual but I can't figure out what this pipe is. It is in the way of the o2 sensor. It comes through the firewall all the way to the front of the car, goes into some kind of cylinder and then back out which then a few of the horns are connected from. Is it just a vacuum hose? It has a nut to separate it right above the 02 sensor.

Thanks again!

 

^ A/C Don't **** with that R12 ain't cheap

 

You're in Cary, NC... is your car a black S5 located on chapel hill by any chance?

 

Move the tabs, remove the nuts.

Leave that line alone! Thats for your AC.

 

Gotcha, Thanks!

alexdimen, Thats not me. This is me http://jc.thetek.com/rx7/, but I know which one you are talking about. I have an office right across the street from that guy!

Are you in cary? Send me a private message and I will give you my msn id!