Since I recently totally rebuilt my 83 slant in my b150 van things have run amazingly until now, I have put almost 500 miles on it and my exhaust has begun to leak at the pipe flange. I changed the gasket, it was leaking again within five miles. I replaced it with a thicker one yesterday and now that one is beginning to leak. I've cleaned off the surfaces and they appear flat as far as I can tell. Any tips??? Similar situations??

This kind of rapid gasket blowout means the pipe flange and/or the manifold flange is warped. Usually it's the pipe flange. Doesn't matter how thick a gasket you install, it won't seal a warped flange.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

any solutions other than getting a new pipe installed at the muffler shop, can I file it smooth??

The thicker one, was it a Remflex gasket or just one of the composite style gaskets?

-D.idiot

I have spent the last few months chasing down the exhaust leaks on my brother's 83 B-150 with a slant.

(1) If your van has it, remove the exhaust line support fixture that clamps on the exhaust line and bolts to the bellhousing below the starter motor. On my brother's van this fixture had been welded wrong and prevented the pipe from sealing correctly.

(2) if the exhaust line has even been replaced at the manifold flange, make sure that the pipe does not stick above the exhaust line flange. Had this happen to me on a couple different cars where the exaust line had been replaced from the manifold back.

(3) if you still have leaks, you *might* be able to grind the flange on the pipe and the manifold flat, but this would require the right tools and the removal of the manifold and the pipe from the vehicle.

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Casually looking for a Clifford hyperpak intake for cheap.

You say appear to be flat.... did you actually take a straight-edge to it? It doesn't take much warping, maybe several thousandths. Bolt the pipe to the manifold without a gasket and snug it down. Take a thick feeler gauge and go around the entire flange. If at any point you can push it in.....

You don't need any special voodoo gaskets for a good seal. Yes the thicker ones made to take higher temps help but they are band-aids at best for a poor flange surface. For moderately flat flanges, a parts store run of the mill gasket will be fine for a stock-ish application.

Been there, done that chasing gasket blowouts. I tried every gasket I could get my hands on with flanges that "appeared" to be flat. Last time I had them apart I took a straight edge to them. Whoopsy... why's that straightedge rocking back and forth?

RedPoncho81,

It has happened to me on several vehicles......
Don't give up, try and clean up both surfaces and file them with a wide flat file if you can. By the way, you can get rid of the studs and drill out the holes to accept bolts. It makes it allot easier to make the surface flat with out the studs in the way. Then purchase a RemFlex RF 6006 for a superior manifold to exhaust pipe gasket. It is much thicker and will conform to poor surfaces. Just don't over tighten it like you would normally do with a FelPro. Snug it up and you will be fine.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Overtightening is never the correct or "normal" procedure, regardless of who made the gasket.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

where would I find the remflex gaskets???

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Casually looking for a Clifford hyperpak intake for cheap.

If you have the room to deploy it, a proper sized piece of 1X4 inserted into a belt sander belt makes a good flat sanding block. I managed to get that into the flange area and sand the exhaust pipe flange very flat. Fixed the persistent leak. Seals with a felpro gasket now.

www.remflex.com or your local auto parts store. Only tighten to 5 foot lbs. In other words these gaskets do not like to be crushed to death from over tightening. They are so thick that they will absorb slight imperfections and seal very well.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

i had the same problem with my duster, i have headers on it two differane sets both brand new, head was shaved straight and i still had leaks. bought special header gasket from clifford that was 1/2 inch thick still leaked. the only way i solved my problem was buying 3 plan exhast manifold gasket kits, taking high temp rtv and rtving the 3 gaskets together. works evertime.

had that for many years.
finally go so frustrated that i pulled the whole pipe out and set in my driveway. first i hit it with a torch and bent the upturned flange fingers back to close to normal. then i took a belt sander to the flange. it was real obvious where the low spot(leak) was. i stayed on it and in a while, i had a surface that never leaked again.

it took a couple hours to get it done.

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68 A108
73 Harley Servicar
71 BMW R75/5
48 Indian Chief
2003 Ford Ranger XLT extra cab
1997 Geo tracker(Suzuki Sidekick)

when i bought my clifford headers i checked them with straight edge out of box and it was warped pretty bad, i sent mine out to local machine shop and had it planed. but even after that i had trouble until i put 3 together.