I changed my exhaust manifold on my 302 two years ago. Now the flange at the exhaust manifold and cat pipe is shot and leaking. Speedy says they can't fix the flange and I have to get a new Cat ($1200.00 new). Does anyone have experience with exhaust flanges? I know you can buy a universal flange kit to seal up pipes together but I don't know about one for this area. I really need help on this one cause I'm not changing cats for this leak. Thank you in advance.

Owl

 

$1200 for a new converter? How does that work out in what costs? That price seems pretty exce$$ive.

Why is it leaking? What is the matter with the exhaust flange?

That determines how you repair it. Is it leaking just because it needs a new gasket?

 

Its leaking because the flange that bolts to the exhaust manifold has rusted away and there is nothing now to hold the two pipes together.
Owl

 

Okay, what you can buy is what is called an "exhaust split flange". Basically, you open it, put it around the pipe where it is bell shaped, bolt it closed. It is usually made of a bunch of thin stacked metal plates with two bolt holes. Cost about $20. You have to know the size of the pipe.

Another method. What I have done, is knock out the bolts or studs from the rusted flange, or just cut them off. Then I use grade 8, 1/4", 4-5" long bolts in the existing holes to grab the exhaust flange on the exhaust pipe. What you do is stack a 1/4" lock washer, on a 1/4" flat washer, on a 3/8" flat washer, on a 5/8" flat washer (about 3/4" wide). This gives you enough to grab around the rusted area AND lifts the bolt head over the flange so you can get a wrench on it.

Use the same setup on the bottom, but in reverse and with a nut. Using an impact gun, lock washers on both ends means you usually do not need a wrench to hold the bolt. If you are doing it by hand, once the lock washer on the bolt end grabs, you usually do not need to hold it to prevent it from spinning.

Just a liberal amount of anti-seize on everything.

I usually tie the exhaust up into position so there is no weight on the exhaust, it makes the work easier.

 

I was just going to post a question about exhaust work, since I'm having a leak at the engine exh manifold. First I had to change the fan clutch today. now that that's out of the way, I can pull the dog house, and take a look. I think I'm entering one of those spells where a bunch of things go wrong...one after the other. I've run Ford vans since 84, and I still think they're difficult at best to work on. I think with gas near $3.00 a gallon. This will probably be my last Ford van. I'll more than likely downsize to a Ranger. Maybe even go over to the dark side [Toyota].
Anyway thanks for the timely posts.

 

Whoa just noticed how old this sub is. I hope Owl fixed his leak 8 years ago, hopefully he didn't get another one in that time. I had a similar problem and found some split flanges in Canada. Maybe this will help whoever stumbled here the same way I did.