fisheric Posted October 20, 2009 Share Posted October 20, 2009 I bought a can of gasket material because my valve cover was leaking out of the top left corner and the guy at the store recommended the stuff. While applying it I broke off a bolt flush. I have a nice cordless drill and a couple cheap bit sets. I don't have any lefty bits, not that I think it would help. I don't currently have a tap/die set but I think I could get one. What is the proper way to do this procedure? Car is an 81 280zx, bolt is the upper right corner if standing at the front bumper Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted October 20, 2009 Share Posted October 20, 2009 (edited) http://forum.grumpysperformance.com/viewtopic.php?f=50&t=729&p=1263&hilit=+rusty#p1263 read the thread linked above, and each of its sub links BEFORE doing anything else short version, go to the local hardware store and ask for a reverse twist drill about 2/3rds the diameter of the bolt,and a matched EASY OUT BIT, use a punch to indent the center of the bolt thats broke off so the drill tip won,t wander,as you drill, be sure the drill is used concentric to the bolt center line,use it or a standard twist drill to drill completely thru the busted section of thread bolt left in the head, soak it in a solvent penetrating oil and use an EASY-OUT bit with a T-handle to spin it out http://www.toolprice.com/product/8304D/10_Pc_Left_Hand_Drill_Bit_Cobalt_Screw_Extractor_Neiko_USA.html Edited October 20, 2009 by grumpyvette Quote Link to comment Share on other sites More sharing options...
waddiejohn Posted October 21, 2009 Share Posted October 21, 2009 I like to start with a #1 center drill. You have to eyeball the center of the bolt for the punch and as you're drilling with the center drill you can make small corrections to get it centered dead nuts on. Corrections have to be made very early in the drilling process so that you don't snap the tip of the cemter drill off in the hole you're drilling. If you don't get it centered just right the first time you can follow up with a #2 then #3 if necessary. Once the cone shape is established you can use a standard 118 degree twist drill to cut through to the bottom. A little practice and you can drill to the minor thread diameter then just pull the threads out with tweezers or needle nose pliers. That's just how I do it. Can't say it's any better than anyone elses method, but I've nearly made a career out of it working with new engineers that are in a hurry and ladies that don't understand torque. Quote Link to comment Share on other sites More sharing options...
waddiejohn Posted October 21, 2009 Share Posted October 21, 2009 Oh, I almost forgot. Don't use a lot of force against the drill. Use sharp drills of good quality and let it do the cutting and don't run your drill too fast. Quote Link to comment Share on other sites More sharing options...
waddiejohn Posted October 21, 2009 Share Posted October 21, 2009 Geez, stuff keeps popping into my head that I do without thinking about it. Getting old I guess. I like to use Tap Magic or cutting oil once I get my hole started. Quote Link to comment Share on other sites More sharing options...
trippintl0 Posted October 21, 2009 Share Posted October 21, 2009 One time I broke off a valve cover bolt. After fighting with it for a while I realized the bolt was sticking out the bottom about 1/4 inch and I was able to use vise grips and unscrew it like that. Quote Link to comment Share on other sites More sharing options...
waddiejohn Posted October 22, 2009 Share Posted October 22, 2009 You know, you never said if you broke the bolt while tightening it or trying to remove it. If you broke it while tightening it the remainder of the bolt could be relatively loose in it's hole. Under those circumstances a Dremel tool with cut-off wheel might be used to cut a slot in the bolt and back it out with a screwdriver. That of course would be contingent on the bolt not bottoming in the hole. Quote Link to comment Share on other sites More sharing options...
fisheric Posted October 22, 2009 Author Share Posted October 22, 2009 grumpyvette, Yeah the reverse twist is what I meant when I called it a lefty bit. I don't have any but... The thing I am worried about is I really cranked that bolt down because as I am sure you all know the design of that valve cover is terrible. There needs to be 1 or 2 more bolts at the very end of the cover because oil leaks out. Thats why I was really putting alot of torque on it. The reason I bring this up is why get the reverse twist(is that the same as a left handed drill bit?) if I put so much torque on the bolt that I broke the head off? Why not use a standard bit and then use the easy out? I was not familiar with the easy out until I followed the link you sent me. I think I might actually have one in my tool box and just never knew what it was. waddiejohn, Sorry I wasn't more clear. I was tightening a new gasket down and the bolt did break off flush with the umm.... what do I call the part that the valve/crank cover bolts on to? Anyway it is broken off flush with that. Hitting the bolt with a center punch so that it doesn't walk on me is a good idea I wouldn't have thought of. Thanks for that. Could you elaborate a little bit on what you mean by: Once the cone shape is established you can use a standard 118 degree twist drill to cut through to the bottom Well tomorrow or the day after I am actually going to attempt this procedure. I am really dreading it. What really irritates me is that the whole reason I was putting a new gasket on is because oil kept leaking out the end closest to the firewall. So I was trying to fix it and just made things worse. Thanks alot for everyone's help so far. I am gonna read those links from grumpy and then check back here before I start drilling. Quote Link to comment Share on other sites More sharing options...
fisheric Posted October 22, 2009 Author Share Posted October 22, 2009 One more question. Do I need to use specific cutting oil or can I use 3-in-1 general purpose, or wd-40? I am currently unemployed so if I can do something cheaper than I need to. However, I do understand that by spending too little to begin with you will spend more in the long run. Unfortunately at this point if I can save $5 by not having to buy a bottle of cutting oil than I would need to Quote Link to comment Share on other sites More sharing options...
waddiejohn Posted October 23, 2009 Share Posted October 23, 2009 I have used a mix of ATF and kerosene for cutting oil, But you can do the job without it. Since you broke the bolt off while tightening it, it is perfectly reasonable to think it may not be tight in the hole. If it isn't bottomed out then it should back out with reasonable ease. Try the screwdriver slot first. The cone shape I was refering to is actually an inverted cone or funnel shape that is cut by the center drill. If you look at an ENCO or Rutland Tool catalog you will see a picture of the drill I'm talking about. In the catalog they refer to them as " Combined Drills & Countersinks ". They are very ridgid and are used to start a hole in such a way as to prevent the drill from walking. I've used them to remove rivets from aircraft skin without enlarging the hole. They're great little tools. Just don't put a side load on the small drill part or you'll break it off in the hole. The 118 degree drill bit refers to a standard twist drill. The point is ground at an angle of 118 degrees included angle. I could just have said " Drill Bit ", but once I start writing about something a little bit technical I can get anal sometimes. Sorry about that. It comes from writing work instructions for semi-conductor assembly staff. Left hand cut drills are neat too. A lot of times it will unscrew the bolt for you as you are drilling if it isn't corroded or tight against the bottom of the hole. I've never cared much for Easy Outs, but do use them on occasion. I have also drilled a hole in the screw and used a three sided burr knife to unscrew a broken bolt or screw. It all depends on it's location or access, material and how tight the screw is in the hole. One more thing. I use " Opti-Visors " with a #5 lens when doing this kind of stuff. It really helps me to see when I've got my center located and I can see if my drill is flexing. Sorry to be so windy, but don't know any other way to relay the info. Good luck. Waddie Quote Link to comment Share on other sites More sharing options...
Zmanco Posted October 23, 2009 Share Posted October 23, 2009 The thing I am worried about is I really cranked that bolt down because as I am sure you all know the design of that valve cover is terrible. There needs to be 1 or 2 more bolts at the very end of the cover because oil leaks out. Thats why I was really putting alot of torque on it.If the head and valve cover are both straight, then a fresh gasket is probably the only way to stop the leak. In my experience with an L6, once the gasket starts to weep/leak, tightening the bolts more only distorts the gasket and causes further leaks. I know you said that you're trying to do this on the cheap, but you may just have to live with a little oil leaking until you can replace the gasket. IIRC, the valve cover bolts are spec'd at 6 lb-ft. Make sure that when you do replace it, that you don't go beyond that or you'll shortly be right back where you are now. Quote Link to comment Share on other sites More sharing options...
deja Posted October 23, 2009 Share Posted October 23, 2009 Waddie is right. If the bolt did not bottom out in the head there's a good chance once you remove the valve cover you can use a scribe or even a screwdriver to spin the bolt out. I did something exactly like this and paniced. A mechanic friend of mine told me the bolt was probably not bottomed out and using the above method it came out easily. Quote Link to comment Share on other sites More sharing options...
fisheric Posted October 25, 2009 Author Share Posted October 25, 2009 well, i am having some trouble getting the valve cover off. The current gasket is a "gasket-in-a-can" type. I have removed the other bolts and cannot find a good spot to pry the valve cover off. Then i just gave up for awhile cause I got busy, but tomorrow I am gonna attempt it again. I am really hoping that the screw did not bottom out. Any tips on getting the valve cover off without damaging it? Quote Link to comment Share on other sites More sharing options...
waddiejohn Posted October 25, 2009 Share Posted October 25, 2009 Carefull use of Exacto knife between head and valve cover. I used to RTV the valve cover and oil pan on my Super Vee and that was how I got I started the seperation. Maybe someone else will have a better idea. Quote Link to comment Share on other sites More sharing options...
fisheric Posted October 31, 2009 Author Share Posted October 31, 2009 Sorry but what do you mean by RTV? Quote Link to comment Share on other sites More sharing options...
waddiejohn Posted November 2, 2009 Share Posted November 2, 2009 Room Temperature Vulcanizing Silcone Sealer, AKA Form-A-Gasket. I like the red stuff, but see a lot of people use blue or black on engines. There are differences in the useable temp ranges and perhaps some other differences. Need to read the label. Have used the red, when properly certified to seal aircraft bulkheads on pressure cabins. Make a trip to the hardware or auto parts store and read the label or check out the McMaster-Carr catalog. Geez, I must have been half asleep when I made the above post. Sorry, I usually proof read stuff but guess I blew it on that one. Quote Link to comment Share on other sites More sharing options...
trippintl0 Posted November 2, 2009 Share Posted November 2, 2009 I stick a long screwdriver in the breather tube at the top and then pry it up, using the screwdriver as a pry bar.. (oops thats a no-no). Quote Link to comment Share on other sites More sharing options...
BURLEIGH Posted November 3, 2009 Share Posted November 3, 2009 One time I broke off a valve cover bolt. After fighting with it for a while I realized the bolt was sticking out the bottom about 1/4 inch and I was able to use vise grips and unscrew it like that. I've done this before too. Not all of them are accesible though. The screwdriver slot works well too. Quote Link to comment Share on other sites More sharing options...
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