Brazing Cast Iron

I have a leaking coupling between 2 exhaust manifolds on a Cummins big truck engine. Could it be brazed up to stop the leak. I don't really have time to shut down and replace them right now. It is made of cast iron.

Reply to
Clif Holland
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Way back when I had my own machine shop I would braze cast iron because it was the only way to save the piece. But today's technology has advanced so much that there may be other stick welding rods capable of doing it quicker than torching. Call a few shops handling Caterpillar like stuff.

Reply to
Wayne Lundberg

You can probably weld it with a nickel rod. Gouge out a vee shaped area around the crack,and weld it while its still hot. Run the truck after welding and put a good load on it to keep the exhaust temperature well up. This should get you through to the next chance for a shutdown to replace it.

Reply to
Tom Miller

Brazing us not likely to stand up to the high temperatures especially if there is a turbocharger downstream. Cast iron welding rod (Ni-Rod) would be the way to go. Preheat before welding by running up the engine temp and then running the engine afterward for post heat. If it is going to crack it will when the assembly cools down. Peening the weld with a small hammer will help to stretch the weld as it cools from a red heat. There are a lot of computerised controls and sensors on modern truck diesels. Keep the ground immediately next to where you are welding. Check your manual for any cautions about welding on the truck. Randy

"Clif Holland" wrote in message news:Cs6jf.3134$to5.2902@trnddc04... I have a leaking coupling between 2 exhaust manifolds on a Cummins big truck engine. Could it be brazed up to stop the leak. I don't really have time to shut down and replace them right now. It is made of cast iron.

Reply to
R. Zimmerman

No. Brazing won't hold up to exhaust temps, particularly on a diesel.

It can be stick welded with nickle rod, TIG'd with nickle rod, or gas welded with "railroad rod" and ferro-flux. The latter materials are hard to find but would be my first choice. I've welded some tricky cast iron with that stuff: some exhaust manifolds, an ornate treadle from an antique Singer sewing machine and an ancient sewer pipe grate that a friend wanted to preserve and restore in the interest of authenticity in an old house with a lot of history and character. She was an interesting person.

"Don, I have this cracked shit pipe so I thought of you." Who among us could resist such a maiden's dulcet murmur?

Ya never really puddle railroad rod; you kinda mush it together, working with metal in a plastic state. It takes a bit of practice and it's not as quick as stick or TIG, but I've found that the job is much less likely to crack, either in the weld or in adjacent regions, upon cooling. Twerks fer me, YMMV.

Reply to
Don Foreman

Hi Clif,

Not only am I interested in the repair technique but I am especially so because I also have an old Freightliner with a Cummins 855.

Could you explain what the coupling is? Is it part of the manifolds? Or does it go into the engine head?

Vernon

Reply to
Vernon

Not sure of your setup - is the manifold actually cracked?

My favourite repair on high nickel cast (whick most exhaust manifolds today are made of) is preheat and tig weld with stainless wire, and controlled cooldown.

Reply to
nospam.clare.nce

This is a Big Cam Cummins engine. It has 3 separate heads and 3 separate exhaust manifolds. One of the interconnecting sleeves is leaking. I was looking for a quick fix on the engine to get by. If I have to remove the manifolds they will be replaced with good ones, not repaired. Brazing could be done on the engine. Welding probably could be but much harder because of location. Looks like it's going to get some high temp expoxy for a temporary patch.

Reply to
Clif Holland

Reply to
Don Young

Those two pieces will move relative to eachother by a good ways when up to temp. You'll either have to remove them and reseal them properly, or find something that can work as a high temp patch and remain flexible. I don't know of anything that would work. Braze will melt out, something higher temp will crack right away, and a solid weld will likely crack the manifold again somewhere else.

Reply to
B.B.

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Preheat with a weed burner if possible

Gunner

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner

Reply to
Gunner Asch

Remember..you can bend your stick rod to fit into tight places. It doesnt have to be straight

Gunner

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner

Reply to
Gunner Asch

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