Am replacing the Catalyst Converter Drivers side for 2002 S-type 3.0 - have been putting it off for a while. Anyway I was able to get one of the two flange nuts off with no issues. The other however was another story - was welded tight - even after using PbBlaster, Impact wrench, breaker bar with leverage was able to get a few turns before the nut sheared off. Left with a stud that is too short for the new Catalytic converter (this the front of the Cat with the flange with two 15mm nuts). Does anyone know what I need to do to replace the broken stud - what do I need to order as a replacement? Any help would be appreciated.

 

Here's a picture of the sheared stud and the good one off the exhaust manifold. The top stud is the sheared one with a spacer. I am thinking of either cutting the stud off flush and then drilling it out. See that the Lincoln LS has a similar stud though can't find it being sold separately. Or consider using this thingmajig The Hush Studfix# . Any suggestions on how to get the sheared stud out?

 

Your best bet is to drill it out. Technically, you should be able to hammer it out, but if its rusted in that bad you will likely have to drill. If you do go that route, you could just replace it with a nut and bolt instead of another stud.

 

Soak it in pb blaster. You can find it in any auto parts store. Let it soak for a few hours if not over night. Sometimes they are threaded on so make sure of that. If not hit it out with a hammer, then use a hardened steel or a stainless steel bolt in its place.

 

Well got the stud out finally. Tried first with a bolt extractor - not enough bite. Cut off the stud below the spacer and knocked the spacer out. Used the bolt extractor and a cheater bar with extension pipe on unthreaded section - came out nice and easy -scratch the easy part. Now off to NAPA to find a stud that will fit looks like a M10/1.25 or 1.5 and about 62mm long. The manifold hole takes the M10/1.5 but is too wide for the metal spacer - may just get a new spacer as well. Picture of top of stud that screws into exhaust manifold.

 

Figured I'd give an update on my experience replacing the Driver's side Catalyst Converter. I replaced it with one of the direct fit Evan'sFischer catalyst converter - didn't want to put too much money into a 2002 V6 that's probably worth 3-4K - enough to get thru NJ emissions testing. Have been driving around with a P0430 for a little over two years. Knew I had fried my cat when my coils went bad on the driver's-side bank and kept driving it for a couple of weeks with occasional flashing MIL (couldn't afford downtime on car). Tried various things and the MIL was intermittent till the past year where it was on. Would have put in the spacer for the downstream O2 sensor to pass emissions but understand that NJ checks under the car with camera/mirror for tampering - not worth the hassle just went ahead and bought the cat off ebay.

The replacement catalyst converter came with a hangar (didn't use it) and a gasket and three holes for O2 sensors. I had to buy a bung at Advance Auto to plug the one extra hole that was on the tail pipe end.

I put the car on rhino ramps and jacked it up higher on the driver's side. Put in jack stands on both sides and removed just the drivers side ramp (left the tire on the passenger side still on ramp). Left the jack and jackstand both in place on driver's side for safety given that I would be doing this on the driveway. Removed the driver's side wheel to give me more room.

a) Unplugged the O2 sensor's both front and back from their electrical sockets. Didn't bother trying to take them off under the car.
b) Used 1/2" 15mm socket with a 12" extension to get the one of the two flange nuts holding the cat to the exhaust manifold. Think I may have used a pipe on a breaker bar first to break it free. The other nut I had to use an universal swivel attachment. This one creaked good when trying to loosen it - was able to unscrew a bit before it snapped - seemed like the threads were mangled up on the bottom (see above posts). Had soaked them with PB blaster previously.
c) Loosened the one bolt holding up the other end of the cat - this is clamp. This one was rusted good - again some PB Blaster did the trick. Loosened it all the way and had to hammer on it to let the clamp spread and loosen grip on the cat pipe. Needed to hammer on end of cat where it's bent to persuade the cat to come out of the exhaust end that it slides into. Not much effort - just awkward trying to use hammer under car. Caught cat before it fell and let it down gently because of the O2 sensors still attached.
d) Original is a Ford cat much more beefier than the cheap aftermarket. The part that holds the substrates does the filtering is bigger and heavier. Anyway removed the O2 sensors from the old cat. Slid the new cat into the tail where the clamp is. Put a hydraulic jack under it to support it so I could keep my hands free. Used a hammer to tap on the bottom end of cat (gently) to get it to slide in. Had to keep switching from back of cat to front to check progress till the flange could fit over studs on manifold. Was a bit of a tight squeeze to get the flange to sit correctly on the exhaust manifold. The exhaust manifold has a metal flared lip. When I removed the cat it did not have any gasket. The replacement came with one wasn't sure if I needed to use it opted to use it and tightening it. Tightened till the flange was flush with the spacers.

e) Started the car and checked for obvious leaks - have to be careful the alternator is spinning right close by. Let car idle for 5 mins and revved up to 2700 rpm (using Eastern Cat guidelines to break in cat). Driving around waiting for the drive cycle to complete. You will smell burning oil - its the cat coating burning off - should clear in a few days.

Should have been a fairly straightforward exercise but for the shearing off the manifold bolt. Worst case was prepared to take to mechanic if things didn't work out. Wouldn't have tried it without a jack that has a high lift and sturdy jack-stands.