rear cat pipe seperation.

[johnceggleston]

i'm working on an ej22 swap into a 98 outback. and the pipe in front of the rear cat has snapped of of the cat at the weld. they fit back together and i hope to find a shop to re-weld it. i assume this is doable?

 

i also have a 96 lego 2.2L for parts and went in to pull the cats today to possibly use on the 98 obw. but it too has the pipe separated from the rear cat. (it also has both o2 sensors in the front cat so i'm not sure i could actually use any of it for the 98.)

 

but i'm wondering if the cat to pipe weld is a common failure point, or is common only on aftermarket cats? or is it something i did while transporting them and off loading them?

 

or is this just coincidence?

[Rooster2]

Prolly just coincidence. I can't see how anything you did could of cause the separation. A good weld job should fix the separation.

 

Good luck on the 2.2 swap out.

[idosubaru]

happens ALL the time, very common. maybe more prominent where there's more rust. i know Davebugs and I see it all the time. really annoying when subaru parts are $500 and the cheap replacements last a year. have it welded.

[johnceggleston]

thanks for the feedback. i'm going to have it welded tomorrow.

 

the 96 cat/s are a different design, 2 o2s in the front cat and nothing in the rear. i wouldn't think that would be a big deal to a 98 ecu but i don't really know. but the 96 also has the rear flange at the donut rusted off and the bung for the front o2 popped out when i was trying to remove it.

 

so, rusted off flange and missing bung, are these also repairable.?? i hate to scrap the cats, they only pay 10$ each for them around here, i checked.

[lmdew]

I've welded a few of them in CO. I think its a weak point of the system.

[davebugs]

10$ cats? Hang onto them.

 

Don't know what they are now worth.

 

Haven't been playing with cars lately but I've got a dozen or so to scrap probably this fall before the holidays when they have a tendency to pay less because they figure folks are selling all they can to get cash for the holidays.

 

As GG said (and I believe I posted last night in another thread) I get that mess with the flanges by the second cat welded all the time at a local exhaust shop. Easiest, cheapest in the long run and a more durable, long lasting solution. They basically cut out the flanges (or what's left of them) and place a sleeve over the ends and weld it up.

 

Seriousely no matter how tight you are this just isn't a place to try and do it yourself to save a few bucks.

[rainman19154]

 

As GG said (and I believe I posted last night in another thread) I get that mess with the flanges by the second cat welded all the time at a local exhaust shop. Easiest, cheapest in the long run and a more durable, long lasting solution. They basically cut out the flanges (or what's left of them) and place a sleeve over the ends and weld it up.

 

 

Great info... I have another thread on this topic and I'm chasing clues to deal wth the problem. Your description with the sleeves completes the advice I've read elsewhere for dealing with this.

 

Do the cats and exhaust system need to come off the car or can a competent welder do it with the car on a lift but everything still in place?

[Rooster2]

Do the cats and exhaust system need to come off the car or can a competent welder do it with the car on a lift but everything still in place?

 

I have not done the welding work, but watched my local cut/chop/weld muffler shop work. They work with the car up on a lift, with the exhaust system attached to the car, then use a support post to hold up and support the pipes in place for welding. The support post works just like a jack stand to hold the pipes up. The welder does have water available to spray around the welded area to cool things off, should the bottom of the car get too hot.

[davebugs]

My guys sawzall off the tubing on the car back to where it's sturdy.

 

Measure, cut a new pipe, often need to expand the ends a little to slip over the existing pipe.

 

Then weld it up. They leave all thehangers connected when they weld it to keep it naturally aligned.

 

Takes them less than 1/2 hour usually.

 

IIR the new piece is 8-10" max. It's been a while so I forget. Varies with rust situation, year of car (distance before the cat IIR can vary a little).

[avk]

I replaced a rusted-off converter flange with a hinged replacement, the better kind that is made of stacked plates. It is held by the remaining weld bead from the original flange. Since the hole spacing is different between the new flange and that on the intermediate pipe, had to use a pair of stainless J-bolts, combined with original springs.