Snapped Exhaust Manifold Stud

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I snapped off a RH exhaust manifold stud during my fifth attempt in 30 days to seal an exhaust leak at the RH Y-pipe/manifold connection of my 1990 RR Classic.

I've had a chronic leak at this location over the last 6 years. I've blown out 3 gaskets on that side, and the nuts are constantly coming loose. I've made numerous attempts to adjust the system to relieve excess pressure on the joint, and I've tried many types of lock washers on the studs. In this last round of repair, I could not get a seal. I noticed that the stud I snapped off was slightly misaligned. I didn't find cracks on either the Y-pipe or manifold joint faces. I did find minor damage to the RH engine mount -- it's buckling about a 1/4".

I need advice on what to do next: I'm afraid that I'll go through a lot of work to replace the studs and the system will still leak.

TJ in KC
1990 RR County

[CJH]

Drop the exhaust to gain a straight shot at the broken stud. If there is anything left to grab, get a good sharp set of Vice Grips, clamp on with all your might then heat the manifold surrounding the stud with a MAPP or Oxy/acetylene torch, hard & fast. It should spin out. If broken flush with manifold face, it must be drilled out. They are small enough to rule out a screw extractor (EZ out). Better to drill & retap threads. Be sure to center punch it dead center & drill straight. As you get close to the final size, the remnants of the old stud may crumble out. Chase threads with a tap.

Check the manifold & Y pipe gasket surfaces for flatness, run a flat file across & look for high spots or warpage.

The problem is either a bad gasket surface or misalignment between the Y pipe & manifold. One way to cure misalignment is to reassemble, snug bolts then heat the Y pipe cherry red to relax the steel, then tighten the bolts to pull the pipe into alignment. Might be a job for a muffler shop if you don't have an oxy/acetylene torch.

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CJH - Many thanks for your advice. I'm grateful!

TJ in KC
1990 RR County

[CJH]

My pleasure. I struggled with something similar. I welded in new catalytic convertors (generic ones), cut & spliced original Y pipe. I had a slight misalignment on the right side flange. Likely happened when I welded those tubes together. Tack welded everything together in-place, but put alot of heat into pipes when finish welding.

Nuts were loose (one fell off), gasket blew after about 6 months. Replaced gasket, nuts loose again when I checked them a couple of weeks later. Looked carefully at gasket, not crushed evenly, flanges misaligned. Got out the oxy/acetylene torch, heated that bitch up about 6" from the flange & tightened up the bolts. Running like a champ.

Good luck, you'll enjoy the silence when you cure it!!

CJH

[tiger]

If you are not up to the "heavy lifting" that drilling out that stud entails, you might try just a c-clamp or vise-grips around the flanges of both the manifold and the exhaust.
After so many years of adressing the same problem, I'd say you have chronic misalignment there, and keep going at it the same way seems like a waste. Maybe replace the pipe already.