I have a baron 55 with io-550 engines. There are some small exhaust leaks where the exhaust stack attaches to the exhaust port on the cylinder. This should be an easy repair except that some of the studs are corroded looking and I think may be damaged or break when the nuts are removed. I have seen a tool to drill out these studs if they should break. These are Rosan type studs so they have to be completely drilled out and the lock ring removed. I regular easy out will not work. I would like to have my mechanic do this without having to pull cylinder. The tool I saw says this is possible. Is anyone aware of this problem and the best way to remove and replace the stud without having to remove the cylinder? I know there are some knowledgable A and Ps on here and any advice would be appreciated.

Thanks for any help provided.

Spray the studs with a penetrating lube, I like Aerokroil made here in Nashville. Give the lube time to work, repeat spray down several times, I doubt if any will break. I have removed several exhaust systems using this manner and have had good results with no broken studs. JZ

I have had success removing and replacing studs on the aircraft, if they won't screw out there are fixtures with drill buhings that can be used. after drilling out the old stud you will have to retap it with a heicoil tap, install the insert and then the new stud. you will need the correct tools .Don

I've followed the procedure Jeff mentioned, with the exception that I favor Mouse Milk. Wait at least overnight or perhaps if you have no pressing time requirements spray and soak over a couple of days. If one does break, pull the cylinder. That's likely to be easier, take less time, and probably more conducive to a good repair than _ _ engineering an in place repair.

Eric,

Another thought... if there's much of a leak, I'll bet the exhaust port will need to be resurfaced, and you'll have to pull the cylinder for that.

Trying to clean up an exhaust port in place is hard, but if very light, I suppose it could be done and at least buy time.

Also, to remove studs, the penetrant (I like Mouse Milk, too, but any good one will work). And heat it up a bit.

Good, luck, and if you can accomplish it in place, please post a report.