Thread: Removing broken manifold crossover pipe studs

'99 - 3800 engine

I need to remove the broken studs at the rear of the manifold crossover pipe (where it connects to the exhaust).

See pic.

I believe these are studs with double nuts and they do not thread into the lower flange. Can anyone confirm? I know the nuts are frozen tight, but can you also confirm that the lower nut is not welded to the lower (exhaust pipe) flange? If this is true, I should be able to just punch these babies through. Just want to be sure before I start banging away.

Thanks

might be best to drill and install new nuts and bolts there.

How did you get them out? I ended up busting both of mine.

wushock2000: DON'T try to hammer, vice-grip, or twist the lower half of those broken studs. You will never get them out by force, and will only make matters worse. Billybooost37 is absolutely correct; the lower nuts are welded on the back of the lower flange.

I learned the hard way - I was able to drill out one of the studs because it broke right at the surface of the flange. But the other one broke off with 1" of stud above the flange and I couldn't get a drill to stay on it. So, I banged on it and ended up busting the lower flange right off the pipe. Luckily, it was a clean break and I found an good welder who was able to wire-weld it back for me by inserting a short collar inside the pipe.

Suggestion: First use a cutoff wheel to cut the broken studs flush with the flange. Buy a 12" long 3/8" bit to drill out the studs. Replace studs with Grade 8.8 M8 or 3/8" bolts. Place bolt heads down, threaded ends facing up. Make sure the bolts are long enough to accommodate both flanges, the donut gasket and the heat shield.

Good luck!!

Thanks for the suggestions. Any tips on drilling out the studs? I've got them cut flush with the flange but drilling has been very slow progress. Using titanium coated bits (made in china) & a 3/8 cobalt bit (made in Germany). At this point I'm contemplating buying a new ZZP rear PLOG.

if you got a center punch punch the stud first, use a smaller drill bit to make a pilot hole, then use a larger one to finish it off. you need a sharp metal bit, firm pressure and go slow, fast dont work, just smokes the bit and kills it. spray some wd-40 on the bit and the flange as you work.

cool, thanks man! I'll give it a go.

dont try to rush it at all. just take your time, cause you'll need them bits to do the other stud. when i say slow i mean real slow, you'll see it shaving the metal off pretty fast, just need to keep at it nice and slow.

Just got it bolted back together & leak free. Thanks for the tips as I couldn't have done it without. My throttle body was pretty dirty so it & the MAF got all cleaned up. I'll post any reduction in IAT when I get around to scanning it. Thanks again!