| Author | Message | ||
     Sfinton |
As many of you know I had a motor mount bolt break off in my front head:  The bolt is still stuck, but has not been drilled out completely. Just in case bought a 7/16 14 nc helicoil kit (stainless steal) and have a few questions to ask: 1. The drill bit to be used with the kit is 29/64 and the threads across the tap is .528 in. Wondering if anyone has put a helicoil in this area and has not had a problem with increasing the hole diameter and interfering with any other bolts that are coming down through the head. 2. Would this increased hole size weakin the area where the bolt goes in, resulting in a crack? 3. When I replace the actual bolt is there a specific specification for the grade of bolt and material (stainless, ect..)? | ||
| Skinstains |
I think Heli-Coil is an excellent idea. Especially if used in location where the bolt will be removed and installed often. What it does is change the surface that the bolt will bind to from aluminum to SS thereby halting the repeated friction and deformation of the aluminum. I would like to put Heli-Coils in every threaded aluminum hole on my bike but my over abundance of laziness prohibits it. I would go for it but can't say I have done it to a front motor mount, maybe someone else here has. FWIW every bolt on the space shuttle is threaded into a Heli-Coil, but of course it was designed to. (Message edited by skinstains on February 07, 2009) | ||
| Ducbsa |
I worked at the place that made the transmissions for Bell and Sikorsky helicopters and all the threaded holes in the Al and Mag housing castings had pressed in steel inserts. Also, didn't XR1000 motors have a lot of heli-coiled holes from the factory? | ||
| Gentleman_jon |
TimeSerts make a thread insert that may have some advantages over the Helicoil in certain applications. Take a look for yourself, and then decide. http://www.timesert.com/ | ||
| Kootenay |
Threaded insert, like the Time-Sert, for sure (I've seen others that use a separate key driven in after installation to lock them in place). When drilling the bolt, are you using a left-handed bit? I'm serious--it makes a difference. | ||
| Aldaytona |
Time-Serts make the threaded area better than new, saw them used at Porsche & Audi. Have used them on my "airhead" I would only use a Heli-Coil as a last resort or on someone else's stuff. | ||
| Sfinton |
Got a hold of a Time-Serts Rep. Yes we carry a 7/16-14 thread repair kit. Price $80.89 The kit includes the Drill, counterbore, tap, install driver and 5 inserts of the .600 length we have other lengths available. http://www.timesert.com/html/inchsert.html#0761 I would also recommend a tap guide to ensure that the hole will be tapped straight. The tap guide is a very simple tool sleeve that has the same diameter hole as the tap outside diameter. Place the tap guide on the applications surface. The lower portion of the tap guide should remain as square as possible to the surface. Turn the tap slowly while making sure the guide remains flush. http://www.timesert.com/html/usefultools.html p/n 37164 price $11.47 Pricey but for 50.00 more than my Helicoil Kit it might be worth it. Anyone else have any advise?? | ||
| Etennuly |
I wouldn't give up on getting the old bolt out without damaging the original threads. The left handed drill bit is a good idea, and there are lots of easy-out type of tools that can back that thing out. Perhaps a little heat is needed or a soak with PB Blaster. | ||
| 213racing |
time serts best way hands down i use them every time on all the bikes i work on when the aluminum gets stripped out | ||
| Gentleman_jon |
+1 Etennuly. Getting broken fasteners out intact is a skill that every home mechanic would do well to develop. Of course having a thread insert on hand is a good idea, but a Time Sert kit isn't cheap. As ET suggests, a liberal application of PB blaster will help a lot, and then heating the area is a good idea as the aluminum will expand more rapidly, pulling itself away from the steel fastener. Often drilling the bolt out with a left handed drill will actually remove the bolt with no further work with an extractor, like an easy out. When using easy outs, make sure to use the biggest one possible to avoid having a broken easy out in the bolt. With a little practice, and a little confidence, you will be surprised how easy the procedure will become. There are other techniques as well, such as welding a nut to the remains of the bolt, or cutting a slot in it with a dremel tool, and removing with a screw driver. | ||
| Sfinton |
I have tried the following: -Dremel Slot -PB Blaster -Professional grade Pb Blaster (cant remember the name but its in a green can) -Heat with a propane torch -Left handed drill bits -Ez-Out ....This thing is not budging. But then again we have not drilled it out completely because we are deciding what to do. | ||
| Etennuly |
I have some older style easy-out tools that are a tapered square with a honed edge on the "Left hand" side that when tapped into the drilled hole in a bolt like that, actually 'cut' a square into the bolt. They are IMHO much better than the tapered left screw type, which by their nature put pressure outward onto the thread that you are trying to loosen up. It looks to me that you could drill that hole a little bigger if needed. That can induce a little more weakness in the bolt. The way I see it when I face this problem; "it is me and this @*#$*^& broken bolt.....whom will give up first?" Those threads grip by stretching. If you can weaken it to the maximum point of not getting the tool into the female threads it will help. All it will have to do is relieve the pressure holding the 'strech' and it should turn out by hand(unless it has thread locker, but a little heat should over come that). | ||
| 213racing |
Did the bolt break going in or out? | ||
| Sfinton |
Trying to loosen. Called a buell dealer in Dayton, OH today and they recommended a heli-coil. I'm confused now. | ||
| Ironweed |
From the looks of your photo the broken off bolt is very near the surface of your cylinder head. Have you tried to back it out using a small cold chisel and ball peen hammer? I would be extremely hesitant to go in there with another drill-its too easy for the drill to go off center and ruin the good threads in the head. I've dealt with your situation many times in the past. I live in Westerville, Ohio. I see that you called a dealer in Dayton. If you are not far from me I would be willing to drive over and give you a hand. I would not apply heat-I keep torches as far away from aluminum as possible. Success rates with e-z out type tools are very small if the existing hole is not close to center. Good luck and let me know if I can give you a hand. | ||
| Sfinton |
Ironweed the bike is outside of Dayton, OH (Where I am originally from) but I'm down in Louisville,KY working. So it has not been touched much besides by my father. I will relay the message to him and see if he can try your suggestion. I may be contacting you in the next month or so. Thanks! | ||
| Ironweed |
Sfinton: My phone number here is 614 882-4019. Would enjoy helping you out. | ||
| Fast1075 |
Here is some sound advice...hopefully not too late...the best approach to the problem is to remove the head and take it to a well equipped machine shop that has what is called an "EDM" machine...using the machine the offending broken fastener can be removed without further damaging the head...you want to avoid installing a thread repair if possible...yes it may be easier, or quicker, or cheaper to drill it out and "fix" it...but that opens a whole other can of worms. A side note on thread repairs...if the thread repair is installed even the slighted bit crooked, the side load on the bolt will either break the head, mount, or bolt (again)...and timeserts are miles better than helicoils...if you are forced to use an insert. |
