Help with exhaust manifold problem

[hpaul]

My son has a 1961 Allis Chalmers with diesel engine. Needing to replace the exhaust pipe and muffler, he proceeded to remove the four bolts that hold the pipe flange to the manifold. Three of the bolts bound at about the half way point during removal and broke off.



To make matters worse the bolt extractors he used to attempt to fully remove the bolts also broke, while imbedded in the bolts. There does not appear to be any corrosion when looking into the bolt holes where the top threads are visible. It was my suggestion that he should have heated the manifold with a torch, prior to attempting to remove the bolts. The question now is what approach should be used to rectify the problem. Removing the entire manifold and taking it to a machine shop came to mind. But in the Deming / Las Cruses, New Mexico area, unable to find a machine shop that will touch the job, even if the manifold is brought in.



Any suggestions would be appreciated.



Many thanks in advance.



Hugh

 

[illflem]

The way I deal with broken exhaust studs is to use an arc welder turned up high with a small rod. Just touch the rod to the stud and it will almost instantly turn red hot. Lot more control than using a torch. The stud will then come out easily when cool. This will also destroy the temper on the extractor and allow you to chisel or drill it out and start over.

 

[bigkid59]

I have used the method that Illflem described and it usually works well.



Once you get the broken pieces out do yourself a favor and use studs in place of the bolts. If you use studs with brass nuts you will always be able to remove them later. Any of the better parts stores will have a good assortment of studs and brass nuts in a wide selection of sizes.



Another tip is that a good parts store or fastener store will have studs with different sizes on each end. I have used studs with 7/16" threads on one end and 3/8" threads on the other. The point is that if the original threads are damaged beyond being usable, you can tap the hole for a larger size and use a stepped size stud that will still have a small end that will fit the bolted on part without any reworking of the holes in it.



Hope this helps!

 

[hpaul]

Many thanks to Illflem and bigkid59 for the advice. Really appreciate it. My son has a friend with a welder and will try to get him over to assist in the next day or two.



The availability of varying size studs is new to me. Great suggestion.



By the way bigkid59, lived for a few years at Lake Sardis. Hope the bass fishing is still good.



Will post the final outcome to my son's problem, when resolved.

 

[Evan A. Beck]

You can also drill the whole business out, and use a Heli-Coil in the enlarged hole. Kind of a last resort...

 

[Joseph Donnelly]

If some of the bolt is stil sticking out the back side, weld a nut on it and thread the mess out. You can also use a carbide bur to grind out the stud and hardened easy-out he broke off.

 

[hpaul]

Just want to thank all those who replied. The problem was solved finally by drilling out the old bolts. This did not work on one and will probably have to drill out larger and use a heli-coil.



Anyway, the tractor is back doing its job.



Great bunch of knowledgeable people on this site.



Hugh