I have a few questions about install.

I tried to install mine tonight, but realized 1/2 way thru I didn't have the right tools

1. What do you remove the O2 sensor with (size wrench)??
2. How did you remove the 3 bolts holding the cat on?? (I got 2 off using a 8mm socket for the end of the bolt/spine looking thing, BUT this MUST not be the right tool, as there was a lot of play and on #3, it just spins..........it was/is so frustrating, I don't know where to go from here???

please answer ASAP, as I have my car partly taken apart so I can finish the job as soon as I hear an answer.

THANX!!!

 

I couldn't budge the bolts even with break free, and I thought it was 14 mm sockets? As for the O2 sensor, I'm not sure. I paid a guy $80 to do it. He had an impact wrench and a lift. Good luck though, do some searching someone else has a write up with the correct sized tools you need

 

I can get the bolts to loosen, BUT the inside of the bolt/screw, instead of using a traditional head, uses a spin head so you unscrew the actual BOLT with that, the 14mm nut is just to cause it to snug and so it doesn't rattle out

 

When the guy took my cats off he had a hand held wrench holding the bolt and an impact wrench doing the turning... Also, you will need some extra bolts and washers, some don't come out of the cats, and don't reset your MPG computer or you will get a light.

 

you need a universal O2 sensor socket, $12 from pep boys. I forget what size the other bolts were, but they were a pain, I took them off 1/8 turn at a time with open ended wrenches. They are hard to get to.

 

Why can't you just use a wrench to get the O2 sensor off? That's all I used, no need to spend $12 bucks on a O2 sensor socket tool, waste of money.

 

You just need a 22mm open end wrench. The box end might work, but you'd have to squeeze the harness side of the O2 sensor through the box end... not sure if it'll fit. You can get an O2 socket if you desire, but I just used a wrench. Just in case you don't know what to look for regarding an O2 socket... it's a standard deep dish looking socket with a large slit cut out of the side for the O2 sensor wires to exit out of. How ever you do it, be sure to totally disconnect the wiring from the O2 sensors before you start cranking on them. This will allow them to spin freely, so you aren't stressing the small wiring.

As far as the upper bolts go, I got the top outside one from the engine compartment. The passenger side is a piece of cake. You just need some long extensions for your ratchet. The drivers side requried the removal of the intake tube on my G35, but that was pretty straight forward also.

BTW, all bolts are 14mm except for the O2 sensor which is 22mm.

 

I must have weird BOLTS holding the cats on or something.

in the end where there is 3 bolts, these are weird bolts. It isn't like a standard screw with a NUT, it is like a piece of theaded posts, with a NUT, BUT the Head of this screw is very small and has a spline type head than is smaller than the threaded diameter (the head looks similar to a TORX wrench (6 small splines).

I have to LOOSEN Each NUT and then the threaded post comes off by using a tool to loosen the weird head. This worked OK with a 8mm socket on 2 of them, BUT not the 3rd.

does ANYONE else have this same type of bolt head??

 

i have that head, you need a socket that look like that.

 

where do you get one???

 

this is sort of what it looks like, only the diameter of the stock is bigger

 

so I guess this is what I need??

where did you guys get one?? Auto parts store??

 

yeap or tool shop like sears

 

or this

 

I wouldn't even dink around with those heads on the bolts. Just slip over a deep dish socket and remove the nuts. Who cares if the whole bolt comes out, just slap it in a vice and twist off the nut afterwards. There's actually a flat spot on the bolt with no threads, so you can't thread the bolt in too far. This is a safe place to clamp down with a vice.

 

HOLY CRAP,

your right!!!

you just undo the 14 mm, and leave the threaded part in and slid them apart ha???

thats right, I didn't notice that they were slightly different sizes, but now that you mention it, I think your right. all you have to do it remove the 14mm nut???

 

you need to remove both the nut and the long screw

on the header, only 1 hole is threaded, so the other 2 holes you will have to use new hardware.

 

ya, there are 2 I got off easily, the other one was in the other way and I couldn't get it out (the one that is in the header, NOT the cat). I guess I just need to keep that on in there and use NEW hardware on the other 2 right????

 

That's what I did on my G. I also removed the one bolt you are having problems with, from the engine compartment. The passenger side is really easy... the drivers side requires the removal of the intake tube from the MAS to the throttle body. All you need are some long extensions (maybe 2-3ft worth), a ratchet and a deep dish 14mm socket (plus a screwy driver and a 10mm for the intake tube).

 

the additional hardware will be used at the y-section, you will need to buy additional hardware.