MOTOBRICK.COM
TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: colly on May 29, 2017, 10:05:51 AM
-
So I took off the exhaust manifold but 3 of the bolts did not come out easily. When I tried to get the frist one out, by putting two nuts on and tightening, it seemed to be moving very slowly when tapping with a hammer but eventually it just sheared off.
What's the best way to get it out?
Thanks
-
I take it this is a stud into the cylinder head? If it has snapped off flush with the surface of the head you can drill it and use an Easyout. I'm sure you will find videos of this on YouTube if you are unsure what to do. Applying some heat to the aluminium around the stud should help to loosen it off. Drill carefully with good quality, sharp drillbits and don't snap them! You may eventually end up having to repair the thread with a Helicoil.
Sent from my iPhone using Tapatalk
-
I take it this is a stud into the cylinder head? If it has snapped off flush with the surface of the head you can drill it and use an Easyout. I'm sure you will find videos of this on YouTube if you are unsure what to do. Applying some heat to the aluminium around the stud should help to loosen it off. Drill carefully with good quality, sharp drillbits and don't snap them! You may eventually end up having to repair the thread with a Helicoil.
Sent from my iPhone using Tapatalk
No don't use an easy out, they can break and then you have a much bigger problem, just lay the bike onto a firm support and carefully drill the old, start small and gradually increase drill size to 6,5mm.
re tap to 8 mm. Remove the fuel tank, seat etc,before you lay your bike over.
-
No don't use an easy out, they can break and then you have a much bigger problem, just lay the bike onto a firm support and carefully drill the old, start small and gradually increase drill size to 6,5mm.
He's right.
Easy-outs can break but they have been used successfully for bolt extraction. Heat and penetrating fluid should be applied before beginning; over-torquing should be avoided or, as wally indicates, the problem increases because you'll then need to drill through the hardened extractor.
If you're going to use the drill-out technique, consider using left-handed twist drills in the same stepped manner that wally describes. Sometimes, midway through the process a left-handed bit will suddenly act as a screw extractor and wind the bolt out of the hole. There's quite a celebration when that happens.
This is another area where Gryph has depth of experience. Maybe he'll chime in.
-
My bike had more broken and seized bolts than good ones when I got it so I have some experience here as well.
I agree that using left hand drill bits is the way to go, they often work just by themselves as noted previously by Laitch. If they don't then you are making a good hole for an easy out to go into.
Heat, oil, even cold, frequent checks of your progress and lots of patience and it will come out eventually, and it if doesn't then a helicoil will work for sure. Above all do not swing no it with huge amount of force no matter what you are doing - that will certainly make things worse not better.
Good luck!
-
If there is still some part of the exhaust stud proud of the surface of the block, screw a M8 nut onto it. That will help to guide the drill bit so that it does not wander and you ruin the threads on the block.
-
Heat and soak it with a good quality penetrant not WD 40. You can make a dam out of plasticine to contain the penetrant. You can also try alternating between heat and freeze spray. Then hopefully left hand drill bits will work.
Regards Martin.
-
Hope this will help.
Regards Martin.
Best Penetrating Oil Test for Rust, Spark Plugs | ATF & ACETONE ... (https://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=13&cad=rja&uact=8&sqi=2&ved=0ahUKEwj03Ji7mpbUAhUKabwKHSt4BAsQtwIIczAM&url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DCESDxCloCoQ&usg=AFQjCNFrB8GLXlFLNEFPyNj7w14wS9qWxw)
-
Colly, I don't want to confuse you with lots of conflicting advice here but there are definite advantages to using an easyout, which I have done many times before. Obviously if you snap it you will just be doubling your problem but if you drill a hole as big as you can to get the biggest one in, don't use a cheap one, and are not too heavy-handed, it reduces the chances of that happening. If you use an easyout you don't have to drill a hole that is dead central and straight, which you will need to do if you are going to use a helicoil. Otherwise your new stud position may end up in the wrong place and/or at an angle. Unless you have the cylinder head removed and set up square and true on a pillar drill or a milling machine it is going to be very hard to drill a central, straight hole into the end of a broken stud. Applying heat will certainly help, whatever you decide to do.
Sent from my iPhone using Tapatalk