Broken Choke Tubes

Don 409

Well Known Member
#1
Hello,
Could someone tell me what would be the best method of removing rusted and broken 409 choke tubes from an exhaust manifold that's off the motor? One is broken almost flush with the manifold and the other sticks up about an inch.
Thanks, Don
 

427John

Well Known Member
#2
Soak it in penetrating oil,and then a small slide hammer dent puller.If that fails file it off flush and use small and gradually larger drill bits until it is gone,if you use care and patience I've seen it done where the tube is drilled out without even cleaning all the rust out of the hole and it remains at its original size.
 
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Don 409

Well Known Member
#3
I soaked it yesterday and tried to tap out the longer tube by clamping vice grips on it and tapping with a hammer. That didn't work. It's pretty rusted up. I guess I'll grind them flush and drill them out. Any idea on what the actual hole dimension in the manifold is?
Don
 

Jim Sullivan

Well Known Member
Supporting Member 8
#5
I haven't messed with choke tubes in a long time. Are they different sizes on each end that fits in the manifold, do they only go in and come out in one direction?
 

Junky

Well Known Member
#8
Looking at the picture at Shafer's Classic, it appears that one side is larger than the other. I would suggest that you purchase a new tube, and check the size of both ends with a micrometer before doing anything else on the manifold. That way, you can drill out what is left of the old and know that the new is going to fit properly. In fact, I might be inclined to making it 1/64 of an inch smaller just so you will have a friction fit. When I was ordering the upper and lower tubes, I forgot to purchase this tube also, and I lucked out, with it still being in good condition. Today, when I went to get the picture (below), I saw the exhaust manifold washers, and the bolt locks, which were both missing from my car when I took it apart, and I wasn't aware of them as being factory installed parts. I will be adding that to my next shopping session. Exhaust Manifold Tube.jpg
 

427John

Well Known Member
#9
Even if it is broken off flush I would still try the slide hammer find a small self tapping bolt the longer the better and carefully thread it into inside diameter of the tube get as much thread engagement as you can and try slapping it out with the slide hammer,don't go overboard and break the bolt off inside,heat wouldn't hurt and neither would the candle trick.heat down towards the bottom of the hole and touch the candle at the top,the melted wax will flow towards the heat.
 

airsurf

Well Known Member
#11
I think the choke tube in my 348 had been broken and just sitting on the hole for 30+ years and with my recently rebuilt carb I noticed the choke would not open fully if it was adjusted to be closed fully when cold. I recently bought a new one, plus an insulating sleeve (which I didn't know existed). I wasn't sure if they tapered at the ends or not. They don't. I finally matched a drill to the size of the tube and drilled out the hole, but not too far down. Now the new tube fits perfectly and the choke also functions perfectly.
 

Junky

Well Known Member
#12
Heads up on the insulating sleeve. I cut mine to fit, and when the tube got hot, the sleeve shrunk in diameter and length. I will buying another, and cutting it a lot longer before installing it. I might even try heating it with my heat gun to shrink it. Once it has shrunken, I will trim it off at the bottom and install the tube back onto the carburetor.
 
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