I found this document: http://www.swedishbricks.net/700900FAQ/Exhaust1.html Here's the important part ------------ Exhaust Manifold Gasket & Studs Replacement. [See the section Turbo: Broken Turbo Exhaust Stud] [Query:] My 744ti currently has 184,000k mi. It is leaking a little at the exhaust manifold so it is time to replace the gasket. I have noticed that it looks like it is the original gasket. I am thinking about replacing the studs and the on the head when the gasket is replaced. Is this a good idea or am I wasting my money. I want to do the job right from the beginning. Applying Penetrants. [Response 1: Onkel Udo] You might want to spray the studs w/apenetrating oil repeatedly for the preceding days. When you reassemble, use antiseize compound on the new studs and coat the exposed areas with a silicone spray or a grease of some type. There is nothing more annoying than trying to remove rusted-in-place nuts on exhaust flanges knowing that at least one stud is going to shear off no matter what you do. Using Heat. [Response 2: Don Foster] If the original studs appear "eroded" (rusted away) and you think you can remove them without snapping even one, then new studs would be a cheap investment. I dearly love my oxy-acetylene torch. Every time I use it, I kiss it. You might also consider replacing the big O-ring in the oil cooler adapter at the same time -- they age, dry out, crack, and start leaking at about the 10-year point with your mileage, and are a B*ITCH to get to -- but with the turbo out, the area's wide open, and access is much easier. In the Event of a Broken Exhaust Manifold Stud. [Query:] How do I remove a broken exhaust manifold stud, broken off below the surface. [Response: Paul Seminara] Got a right angle reversible drill? Got a moto or air grinder tool? Got some diamond bits? Got a locking collar type stud remover? Got the appropriate size left hand cobalt drill bit? Got the appropriate drill and tap? With the above tools it's actually not that bad (BTDT). Start with the left hand drill bit (smaller than the stud in question, correct size for stud remover) with the drill in "R". Maybe the stud will come out maybe not. If not give the stud remover a shot. DO NOT, I REPEAT DO NOT EVEN THINK OF USING AN EASY OUT. If the stud remover fails or doesn't cut it you must go into full dentist mode with your high speed tool and diamond bits. Just follow the stud and don't go outside the envelope. When most is gone simply drill the hole to the correct size for the tap. Clean hole. Tap, clean and insert stud. Done. [Cautionary Note] I have fixed broken head studs three times before, on different cars. On all of them I pulled the head and used a drill press and "easy-out" to remove the stud, also lots of heat. You can buy an easy-out/drillbit set at most autparts and machinist places. The drill press ensures an accurate hole (remember, the head is softer than the bolt; you don't want to miss!) It was pretty easy. Removing a Broken Stud with a Right-Angle Drill. [Tip: Bob Mohr] Been there, done that. A right angle drill will work just fine. I'd suggest using a diamond bit in a Dremel rotary tool to put a nice, centered starting "dimple" in the middle of the broken stud to prevent the bit from walking once you start. You shouldn't have to buy a special diamond tipped drill bit. I went down to the local industrial supply and purchased a cobalt bit that went through that old stud like a hot knife through butter. Have a bottle of cutting oil nearby and squirt a little in the hole every quarter inch or so to cool the bit and flush out the shavings. I ended up drilling it out oversized and installed a helicoil. It worked great. Another tip if you don't have a right angled drill. I used one of those fiberglass reinforced cutoff wheels in a dremel to reduce the length of my cobalt drill bit. You have to be careful chucking the drill bit, as it's tough to get it in straight. Cutting down the drill bit gives you just enough clearance to get a straight shot at most of the studs with a plain jane 1/4" drill. DANGER, DANGER, DANGER! Do not attempt to drill a hole in the stud and use an extractor/easy out. The extractor can and probably will break off in the hole. Then, your available options are reduced to pulling the engine and having a machine shop mill out the extractor/old stud or spending 24 hours and a dozen diamond bits to hog out the broken extractor millimeter by millimeter. It ain't fun! Both Seminara and I both went through this torture! [Tip 2: Dick Riess] Have done it with the 90 degree drill, unfortunately w/o diamond bits and kinda made a mess, but my machine shop friend let me use his Time Cert outfit to fix it. Evidently the Time Cert is used extensively on hopping up the old aluminum VW engines. They just don't come out. So if you mess up the threads, there is still hope. BTW, I am going to have to get some of those diamond bits from Paul---they sound like a life saver and you can count on needing them eventually. Replace All with Stainless. [Response 3: John B ] wouldn't fix the stud problem if it's not a problem. OTOH, if you break one stud in the process, might as well replace them all. I think IPD has a stainless steel stud/bolt kit? Turbo Notes. When you pull out the manifold/turbo, then's the time to replace the turbo/tube and tube/block gasket and O-ring. Even if you don't pull the entire manifold/turbo out to replace the exhaust gasket (best case) the turbo oil tube is a lot easier to reseal with the manifold loosened (and the two bolts holding it onto the turbo removed). How's your 02 sensor? It's easy to get to with the manifold out. Painting the Manifold. [Tip from Tom Irwin] Don't paint your exhaust manifolds, even with hi-temp paint, no matter HOW COOL it looks! The paint burns off under the bolt heads and relieves bolt compression. Almost ALL were under torque spec. [Editor] Probably OK to paint IF you don't paint under the bolt heads. Yahoo! Groups Sponsor <http://rd.yahoo.com/M=249982.3512844.4795476.1261774/D=egroupweb/S=170512 6215:HM/A=1524963/R=0/SIG=12o72ctft/*http://hits.411web.com/cgi-bin/autore dir?camp=556&lineid=3512844?=egroupweb&pos=HM> <http://us.adserver.yahoo.com/l?M=249982.3512844.4795476.1261774/D=egroupm ail/S=:HM/A=1524963/rand=172897699> To unsubscribe from this group, send an email to: DMCForum-unsubscribe@xxxxxxxxxxxxxxx Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service <http://docs.yahoo.com/info/terms/> .
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