anybody know how to install cats?

[cab2g]

I just bought a set of used high flow cats and I want to try to install them myself, but I hear horror stories of stripping the o2 sensor threads. What truly is the best way to remove the o2 sensors? Anybody want to help me do the install?

[huggerorange73]

I just bought a set of used high flow cats and I want to try to install them myself, but I hear horror stories of stripping the o2 sensor threads. What truly is the best way to remove the o2 sensors? Anybody want to help me do the install?

I've done 3 sets of headers already....none stripped yet. Spray a little WD 40 on the threads for a couple days leading up to the removal ( when the car is cool of course, overnight is ideal ) and if need be a little heat right before you remove them.

If you're close to me I can give ya a hand....I'm in Norridge.

[cab2g]

Some people were saying that the exhaust should be hot, as in run the car for awhile before removing the o2 sensors. I didn't think that made sense because it would make the metal in the sensor expand and make it harder to take out! But that's what I was going to do. WD-40 makes more sense. I live out by lake barrington, so not too close, but if you're free next weekend, I could use a hand!

[HumanWiki]

Some people were saying that the exhaust should be hot, as in run the car for awhile before removing the o2 sensors. I didn't think that made sense because it would make the metal in the sensor expand and make it harder to take out! But that's what I was going to do. WD-40 makes more sense. I live out by lake barrington, so not too close, but if you're free next weekend, I could use a hand!

Different metals will expand at different rates when heated... That could be the basis of that idea. The heating could serve to expand the bung on the exhaust making the O2 threads not fit as snug leading to less torque require to take them out.. (just a guess)

[bannonm]

The O2 sensors are in the pipes on a cat back system? I just bought a set of Borla S-type cat back and no where in the directions does it mention removing/replacing the O2 sensors. I thought they were before the cats. Am I mistaken?

[HumanWiki]

^ If yours is a Cat-Back.. It connects to the catted pipe and goes back from there.. The stock pipes you'll connect to that remain already have the rear O2 sensors in them. You won't need to remove them.

OP is talking about HiFlo cats which can be bought that replace the catted connection pipes.

[bannonm]

^ If yours is a Cat-Back.. It connects to the catted pipe and goes back from there.. The stock pipes you'll connect to that remain already have the rear O2 sensors in them. You won't need to remove them.

OP is talking about HiFlo cats which can be bought that replace the catted connection pipes.

Phew, thanks for the clarification. I was starting to sweat.

[HumanWiki]

Phew, thanks for the clarification. I was starting to sweat.

I just looked at the Borla S-Type install instructions... You'll see when you're up under the car.. There's a slip-fit band clamp that you'll loosen and pull the middle section of the exhaust out. The piece that remains up towards the engine you'll see bolting up to the exhaust manifolds and will have both cats and sensors in it. You're replacing the mid-pipes + axle section and stock cans and tips.


Stock V8 Manifolds + Catted Pipes.. -- This is what you'll be hooking in to with your S-Type.





I'm assuming you're a V8......

[bannonm]

Yep, SS2. Thanks

[cab2g]

got my cats in the mail yesterday. I can't wait to install them. The installation instructions also say to remove the system including o2 sensors cold. So that's definitely what I'm going to do. At least that way I don't have to worry about burning my hands or buying heat resistant gloves or something. I had to buy some new stainless bolts a couple gaskets though. The guy forgot to include the bolts and I'm assuming you can't re-use a gasket...

[libertyforall1776]

Might want to try a little PB Blast with its capillary action, as opposed to WD-40, esp. if there's any rustiness...

[cab2g]

ok, well, I am having the hardest time getting the o2 sensors out.... this is crazy. I applied PB blaster about 3 times and the exhaust is cool... I tried hammering the wrench, but that only seems to cause it to slip and tear up the bolt... if only those darn wires weren't attached I could use the impact wrench!

[cab2g]

I figured it out. the wrench slipped too much, so I rented some o2 sockets from oriley auto parts and after all the pb blaster, they came out using only my torque wrench. Unfortunately, the one I hammered the wrench on stripped some of its threads and I couldn't get it back into the bung. So I guess moral of the story is, use the right tool for the job and save $80. But the car sounds awesome now. I definitely don't feel the need to upgrade the exhaust anymore! the idle is quite a bit louder and WOT is heavenly. It's a great poor man's upgrade!