Repairing Cast Iron

[roy697]

Good morning all. The exhaust manifold on my FT 404 is broken off just before the four bolt flange. Question is with the rest of the exhaust system supported on this would a weld repair support the weight of the muffler & vibration of the tractor? I am not having any luck finding a direct replacement. If you have a local dealer that may have one please contact me.

[e-mail]

The manifold flange drops down from the middle & turns away from the tractor.




The new style manifold is different & uses a 2 bolt flange.



The drop down part would help keep water from getting into the engine but also gives clearance for the hood. The manifold can not be seen with the hood down.

[studor]

I had a similar problem with a manifold on an old Massey a few years back. When I took it to a local weld shop they put a piece of thin wall metal tubing in between the two pieces as a placement holder and welded it back together-- it took a couple of attempts because it had been badly welded before but in the end it created a very strong joint. I think a similar weld would work on that manifold-- JMHO

[Rich Waugh]

Roy,

What Studor refers to is pretty much the way I would do it, too. I'd actually put the manifold in the mill and bore a nice round hole to fit my sleeve into and then either weld or braze the sleeve in place. Following that, I would either machine the flange piece (if you still have it) to fit over the sleeve and weld or braze that. If the flange piece is missing, then I'd make the inner sleeve a size where the o.d. is a good fit into a piece of reasonably heavy wall DOM pipe upon which I could fabricate a new flange.

Some cast iron welds tolerably well (generally "malleable" cast iron) and others (white or grey cast iron) often weld so poorly that the welding process generates new fractures faster than they can be fused together. That's why you see so many old cast iron pieces repaired by brazing - its nearly as strong as the original piece and is much less likely to cause additional stress cracking, plus it is more forgiving of vibration than welds. I think such a repair would hold up fine for you. You'll want to find someone who knows what he's doing, though - don't think that just any old welder can do this right. only about 10% of the welders I've seen could do it so it would hold up in use. Ask your local implement or trucking company who they use and go to that guy.

Rich

[psj12]

I would attempt to braze it. A reinforcing piece of steel can even be brazed on top of the cast iron braze.

If you do weld it you should heat the entire part very hot in an oven to prevent stress fractures and then put it back in the oven when done welding to cool slowly.

[bradblazer]

Did you buy that new manifold? It might not be too hard to make an adapter plate to mate the 4-hole and 2-hole flanges. Worst case make it out of 1/2" thick plate. Holesaw the center, drill and tap 6 holes, and trim the bolts so they don't stick out the far side of the adapter.

Otherwise the welding / brazing advice given was good.

[roy697]

Thanks for all the input. My past experience of welded cast is not so good so I will hold off for now, waiting to hear from some tractor places that I called. They all seem to be willing to check for the parts. I will give them a few more days before I have to make up my mind.



I think I may get my oxygen bottle filled & attempt a temporary repair. That way I can have the tractor up to a test drive today. The radiator is on its way here. ;D

[roy697]

Well had some small setbacks. Tried to use my torpedo heater to preheat the manifold, didn't get it hot enough.


As you can see in the pictures my attempt at an oven didn't work very well. could not get it hot enough to braze it correct. How ever the piece seems to be staying intact. The braze job is the worst I have ever done, just could not get enough heat, any how it is holding for now. Some minor leaks with the antifreeze & fuel system, taken care of. Then we were able to start the engine & let it run for about 15 minutes. Didn't get hot enough to start the antifreeze circulating, ran out of time today. Tomorrow we should be able to start it & check the clutch & gear box.

[PJ]

Roy, remembering from years ago, My dad repaired a crack in an engine block. It was in an old Chevy truck with a cast iron 6 to be exact. He heated about 6 to 8 inches around the crack until the crack was cherry red with a rose bud. Another fellow kept the area hot while he brazed the crack. I think he grooved out the crack before he began the heating/welding operation. All I know is it held and never leaked after that. The truck was used for pulling logs out of the woods for years.

[bradblazer]

A weed burner torch makes a good preheater. I have the plain one (second one listed below) It's rated at 500,000BTU / 3500 degrees.
www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=91037
www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=91033

[roy697]

Thanks. Both use propane, I have used a hand held propane torch before, similar to these. The tractor run today, while I was focusing on the engine I didn't realize that the hydraulic pump was not pumping fluid. After the engine warmed up we tried the 3point & no movement. Don't know if pump was bad when I got it or if I ruined it by not getting into it before I got working on the engine, Bummer. We did find out that all the gears & the clutch work. The temp fix of the exhaust is holding but I don't have anything hanging on it, no weight.

Roy

[roy697]

I have been unable to find a direct replacement so I will use the one I got from Affordable Tractor & make it work (pictured above in this post). It was great to hear the tractor run.