V6 Exhaust manifold stud

They are improved. I've yet to see anyone complain of a second break with the new studs. That isn't to say it doesn't happen, but I've not seen it here.

Bob

What bad things can happen if I decide not to replace the broken studs?

- Dave

- The exhaust manifold warps and you have to plane it or replace it. It's possible that's already happened.

- You fail inspection or get asphyxiated due to an exhaust leak

Bob

Neal, just make sure you replace *all* the manifold studs when you do the job, not just the broken ones. Also check the manifold for warpage. Have them machined and you'll be good to go.

For the group: yes I finally did the studs on my '95 Pathfinder a few weeks ago. Terrible way to spend a day and a half but a proper screw extractor set and a DeWalt right angle drill made the SOOO much easier. Here's the link for those interested:

Home Depot carries them for around $190.00 so you'll still save a few hundred on labor doing it yourself and when you're done you have a nice new tool added to your inventory. ;-) Don't forget some titanium coated drill bits and the screw extractor set and you're good to go.

Wil

What did you do to make sure you were centered when drilling ? Also, did you just drill and extract, or did you have to drill some of them completely out to the edges ?

Bob

I just used my `tricks' I acquired in the few years I worked in the Nissan shop. :-)

Basically I have a `feel' for this crappy job now. LOL

Seriously though, I soak the guts out of everthing the night before with Liquid Wrench and use it VERY heavily while I'm removing the nuts that hold the manifolds on. Sometimes you just get lucky and the studs will back out with the nuts. That happened on all but one on the passenger side of mine. Talk about luck!

Once the manifolds were off and the non-broken studs were removed I used a punch and a small ball peen hammer to heavily `mark' the center of each broken stud. Make sure your punch has a fine point and it will give you enough of a `dent' that when you start drilling with a

1/8" titanium drill bit (my preffered choice, but I'm sure cobalt or something similar would do just as good) you won't wobble off center. The MAC Screw Extractor set comes with a set of centering devices for each size drill bit in the case but they are quite cumbersome to use in close quarters although they do work great. Once you've done your first couple of studs, you'll get that `feel' for everything.

After the 1/8" bit, I enlarged the hold to 3/16" (I believe that was the size). Then I used the #2 extractor from the MAC Screw Extractor kit to remove the stud. When you drill, DO NOT go too far or you chance going all the way through the stud and into a water jacket. Should you do this, perhaps some J.B. Weld will save you but it's better to compare a new stud for length and put some tape on your drill bit to act as a marker of the maximum depth you want to drill out. It takes a few extra minutes to do that but then you'll know for sure you're not going in to far but yet you're going deep enough to give the MAC extractor an excellent bite. Also, don't forget to keep back out the drill bit to clean out the hole as you go. You're not trying to get it all done in one pressing action.

A tip for removing the old stud from the extractor so you can reuse the MAC extractors:

clamp the unused end of the extractor in a set of vise grips and then put another set of smaller vise grips loosely on the extractor just against the broken piece of stud it's holding. Tap against the smaller vise grips and the old stud piece will pop right off of the extractor. If the extractor doesn't look to have a `twist' to the area where the stud piece was, you can resuse it.

Wil