PeachParts Mercedes-Benz Forum - View Single Post - How can I remove broken bolt on exhaust manifold?

flash123 · #15 05-02-2004, 02:59 AM

Regarding the ticking sound.

A leaking exaust manifold is usually temperature dependent. Expect it to be louder when it's cold and quiet down some as the metal warms up. If there is a piece of gasket missing, it will always leak.

A broken stud does not guarentee a leak. Sometimes cars don't even have bolts in the first and last holes. Some chrysler 318's just had pins in the end holes.

There is just so much a mechanic can do. If you need a miracle, find an independant muffler shop. You need an old guy that has been making miracles happen since dirt.

Some tricks he might use:

Weld a nut over the broken stud. Stick a nut over the stud, and weld the stud inside the nut. I have done this even when the stud is broken off slightly below the surface of the head.

forget the propane torch. You need a lot of heat, fast. You have to get the metal around the broken stud hot, really hot, like soft without heating up the whole head. then work quickly, carefully, skillfully to work the stud loose.

Whack on the stud with a hammer and punch. This works well if the area around it is really hot. This tends to break the bond between the two different metals. This technique is even better before you break the stud off.

Drill out the offending stud with a left handed drill bit. Sometimes you get lucky and the bit jams and jerks the stud out like magic. Or use a stud remover. It screws into the hole you drilled and jams. it's a left hand thread so as you screw the tool in you are putting preasure to screw the stud out. BTW I have no idea where to find a left handed drill bit. I have been in shops that had them.

Remove the manifold and put it back without a gasket. Smear Henry's roofing tar on the manifold surface before putting it back together. Forget any of the stuff that is made for sealing manifolds or exaust pipes. I did use some tar from a muffler supplier on occasion, but is was still roofing tar, just more expensive. A quart of Henry's lasted for a long time even with every day use. You might get lucky even if you don't get the stud out. BTW if you don't find Henry's, other brands will do. It also works gread for sealing wounds on trees. I use it to protect the wound after pruning or grafting branches. Some people even use it for fixing leaky roofs.

Any machinist can drill out the stud with the head on the bench. If you were pulling the head anyway don't even sweat trying to get it out, let the machinist do it.