Broken stud bolt (valve cover bolt)

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  • Hoffbrohaus
    E30 Addict
    • Sep 2013
    • 519

    #1

    Broken stud bolt (valve cover bolt)

    Torqued the valve cover a little too much and broke off a stud. I was able to get it out with vice grips. I found the part #. Question is where can I pick one up locally tomorrow? It's my DD. Do you think BMW will have them? Doubt autozone or O'Rielly will.

    Also I didn't see a part # for the longer studs that the plug wire loom attaches to. Anyone know what it is? http://realoem.com/bmw/showparts.do?...10&hg=11&fg=15

    Can I just go to Ace hardware? What kind of metal do I want? Thanks in advance?
    '90 325is
  • tinkerputzer
    E30 Addict
    • Jun 2008
    • 508

    #2
    Just run a bolt (with same thread pitch and diameter) in temporarily until the studs come in. They'll most likely have to be ordered.

    Comment

    • digger
      R3V Elite
      • Nov 2005
      • 5911

      #3
      that or get a long bolt and cut the head off
      89 E30 325is Lachs Silber - currently M20B31, M20B33 in the works, stroked to the hilt...

      new build thread http://www.r3vlimited.com/board/showthread.php?t=317505

      Comment

      • raudonis
        Advanced Member
        • Jan 2013
        • 184

        #4
        I had the same problem after valve adjustment, but I was torquing strictly to the spec.
        Took a zinc plated 8.8 class steel bolt, cut off the head to make my own stud. No leaks or other problems after ~500 miles.
        Had a suitable stainless bolt to cut, but chose regular steel because stainless does expand much more when heated.
        My transaction feedback on r3vlimited :):Clickety click

        Comment

        • Hoffbrohaus
          E30 Addict
          • Sep 2013
          • 519

          #5
          Done. Thanks guys. Went to Ace Hardware and got the M6 bolts I needed and cut the head off.
          '90 325is

          Comment

          • not_a_kiwi
            Noobie
            • Jan 2014
            • 35

            #6
            Thank the Bavarian gods this was here ha ha I just did the same thing.... I couldn't believe it because I used a torque wrench and everything

            Comment

            • crappycoco
              Wrencher
              • May 2014
              • 250

              #7
              Motherf*r just snapped on me too. God damn it.

              Comment

              • turbo55
                Wrencher
                • Jul 2014
                • 223

                #8
                This also happened to me, also before I got to the torque spec. Just curious, which stud broke for you guys? For me it was the rearmost one on the passenger side.

                Comment

                • crappycoco
                  Wrencher
                  • May 2014
                  • 250

                  #9
                  The last one to tighten nr. 8 - lower right side, by the timing belt cog. I was even undertorquing it by a bit 14.5Nm instead of 15. :/

                  Anyhow, ordered 8 new bolts, some locking pliers and new nuts.

                  Comment

                  • lcoleman
                    Grease Monkey
                    • Jan 2009
                    • 331

                    #10
                    Any decent hardware store, some/most parts stores, HD or Lowes....lots of places to find a 6x1mm stud.

                    This kind of thing is why nobody uses a torque wrench on valve cover bolts.

                    Comment

                    • crappycoco
                      Wrencher
                      • May 2014
                      • 250

                      #11
                      So they do what? Just tighten until snug? I really dont want to break one again, but I want to do it right.

                      Comment

                      • Ether-D
                        R3VLimited
                        • Sep 2011
                        • 2838

                        #12
                        I've never used a torque wrench on some valve cover bolts, but I'm from TN. I usually go by this method unless it's real important...
                        finger tight +/- 1 ft/lb
                        hand tight +/- 15 ft/lb
                        forearm tight +/- 30 ft/lb
                        good-n-tight +/- 50 ft/lb
                        real good-n-tight +/- 80 ft/lb
                        gorilla tight +/- 200 ft/lb
                        Originally posted by Andy.B
                        Whenever I am about to make a particularly questionable decision regarding a worryingly cheap diy solution, I just ask myself, "What would Ether-D do?"
                        1987 325iS m30b34 Muscle car (Engine electrical phase)
                        ~~~~~~~~~~
                        I was born on 3/25…
                        ~~~~~~~~~~

                        Comment

                        • crappycoco
                          Wrencher
                          • May 2014
                          • 250

                          #13
                          Originally posted by lcoleman
                          Any decent hardware store, some/most parts stores, HD or Lowes....lots of places to find a 6x1mm stud.

                          This kind of thing is why nobody uses a torque wrench on valve cover bolts.
                          Btw, I'm still looking for that goddamn stud. I've ordered new ones from bavauto and when they eventually arrived (after 14 days), they were M6X0.75X35mm - Which is 5mm shorter than what I've pulled from my head.

                          I've checked pretty much all places they stock, make, sell bolts/studs in the bay area and they don't have anything that's finer than 1mm thread pitch. If they do, its too short.

                          What I need is M6X0.75X40 - but in the OEM parts catalog the same part is not illustrated correctly (it has a non-threaded section in the middle) and the size is M6X35 (no mention of the finer thread).

                          [part #9]
                          http://www.realoem.com/bmw/enUS/show...diagId=11_1910

                          How do I know the thread is less than 1mm? Thats because I've ordered 8 M6X1X40 studs and they don't fit. Also, I've ordered the "original" part and its too short. When I've test fitted it, not even screwing it all the way in to the bottom, and with the gasket and cover on - the nut barely screwed on two threads. My amateur mechanical sense tells me thats not right =)

                          So, I've called:
                          • Home depot
                          • O'reilys
                          • SF BMW dealership
                          • Mr metric
                          • east bay bolt company
                          • Many online shops
                          • Fastenal
                          • Autozone
                          • Bavauto
                          • Pelican parts


                          When I asked the bavauto guy what to do he replied with this:
                          I would set them in just enough to hold and see if you have enough coming thru the cover… if so then set them at that depth with some Loctite …
                          So, now I wonder - is that the way you should be doing that? Because it does not sound ok to me.

                          I don't really understand why it's so hard to get a simple stud. And I'm kind of amazed nobody had this problem before. Pls halp r3v.

                          Comment

                          • jalopi
                            Banned
                            • Aug 2010
                            • 2370

                            #14
                            mcmaster doesn't even offer m6x.75... that should be your first indicator that these studs are probably some BS BMW one-off-special kind of threading that they deemed necessary for whatever reason

                            do what the bavauto guy suggested (sans loctite for now) and keep unscrewing the stud from the head until you have a reasonable amount of thread showing through the valve cover to put the nut on. just remember, it's not structural or holding anything up, it's just keeping the valve cover in place. no need to have full threads for strength or anything

                            Comment

                            • crappycoco
                              Wrencher
                              • May 2014
                              • 250

                              #15
                              I'll try that then =) Thanks.

                              Comment

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