tortured by exhaust bolts

**ltbrett** · 04-26-2017, 05:53 PM

I am about as frustrated as I've ever been wrenching on a car. And I'm old. There are four of these bastards on the exhaust manifold downpipe leading into the cat pipe.

Yes, they were seized with rust. So I cut them off in order to drop the exhaust. So far, only mildly annoying. Now, the splined shaft is seized in the flange. I have good access from directly beneath the flange face. There is no access above the flange. I've tried heat, PB blaster, air hammer, 5 lb sledge, and now I've drilled them out. I drilled them through with a 1/8 bit, then enlarged the hole to 1/4 leaving about 1/8 at the end to hit against. I repeated the heat, sledge and air hammer. I'm afraid I'm going to crack my manifold. I've pulled engines in less time.

To make matters worse, I'm working under jack stands, so there's no space to take a real swing. Then again, a real swing would probably crack the manifold by the exhaust port. I suppose I'm posting just to vent, but if anyone has dealt successfully with these beasts, please enlighten me. The "easy" answer of completely drilling them out and replacing them with regular bolts is complicated by the inaccessibility of the bolt heads above the flange, which is why they are splined. Here's the diagram (#10):
https://www.realoem.com/bmw/enUS/sho...diagId=11_1250

Brett