iiipriceiii

Hi everyone I have a 05 fx4 need to do the famous imrc replacement..., my cats are shot and not covered under warranty. I found some Flowmaster and MagnaFlow replacements direct bolt o I will buy there pricey but better than dealer. MY question is it looks tight can I just unbolt the factory stuff and drop them out with out any cross members being removed ???? Has anyone replaced thereselfs???? Thanks for all your help steve ohio

putermech

Welcome to F150Forum
I plan to go with Magnaflow myself this spring. Already have cat-back in place.
Should be straight change out. Might need O2 extentions though. Also purchase replacement O2 sensors, you will see the difference new verses factor. I had to replace one when I broke it while changing out the right manifold. Remember the exhaust noise will be loud with high flow cats.

johnny_tucson

So are you guys saying that the cats aren't welded in? That is to say that one may just unbolt the old to replace with new then just bolt it back up?

betty_white

Cats are welded on, atleast on my truck they were. I have a 2007 lariat super crew 4x4. I just welded pipes in place and got spacers for the o2 sensors so that way it doesnt think theres is to much exhaust emissions goin out with single in single out 40 series flowmaster exhaust single in single out turndown over the back axle. it sounds amazing and has a bit more power without cats but not everybody likes that, just a suggestion.

putermech

Cats are welded to pipe but they have three bolt flange on each end of the pipe.

izzysplace

On my 05 the Cats are bolt in they are just in assemblies, cats welded to pipes that are already bent and flanged. the Left and Right sections fit together with a slip joint and compression clamp. It is pretty easy to change on a 2WD you just need a long extension to get the bolts out at the manifolds

betty_white

yea i saw that just didnt want to replace the whole pipe and i have access to a welder so it was just easier for me to just put a short piece of pipe in.

JimmyB1232

I replaced both of mine with the Magnaflow Direct fits it was fairly easy putting them in. I had to cut off about 3" due to aftermarket exhaust. I had to use a 1/2" impact gun to break the bolts loose on the flanges (even with PB Blast but I do have a crippled hand lol). If you have the right length extension, an impact wobbly and a good quality ratchet and socket you'll be good.

johnny_tucson

Hey guys, is there any way to replace the cats without any welding? Like hose clamps or anything. I am just thinking it would save me so much money not having to pay someone to weld for me.

betty_white

Yes there is but in my experience the the amount of extra pipe and the cost of getting it welded I don't think is that big of a difference. If you already have what you need most muffler shops are fairly good priced just to weld but it might just depend where you live. Call some shops and see.