What's the best way to remove a broken stud, I have one that has broken off and needs replacing, being unerneath the engine it's awkward to do... From what I can gather I can attempt it with a left hand drill bit or a broken stud remover tool, but what would you recommend ? Any tips would be much appreciated.
Not a fun job with the engine in the bike. Any broken studs into alloy or other soft metal I really like to get them set up securely on the pillar drill and drill out the stud to the core diameter of the thread. Done accurately, you will be left with a little spiral of steel much like a helicoil which removes easily enough with a scribe or small pick. Not much help in your situation mind you...
With it in the bike a stud extractor is worth a shot. Hopefully where it is it shouldn't be corroded too badly into the casting as it'll be all oily (are they tapped right through into the crankcase or are they blind holes?) so I think you stand a good chance with an extractor. Another way to get a snapped stud moving is to punch them round anticlockwise but not recommended on something so small and surrounded by nice soft aluminium...
I assume it has broken flush with the casing?
Quote from: Calum on 08 Mar, 2021, 17:58
Not a fun job with the engine in the bike. Any broken studs into alloy or other soft metal I really like to get them set up securely on the pillar drill and drill out the stud to the core diameter of the thread. Done accurately, you will be left with a little spiral of steel much like a helicoil which removes easily enough with a scribe or small pick. Not much help in your situation mind you...
With it in the bike a stud extractor is worth a shot. Hopefully where it is it shouldn't be corroded too badly into the casting as it'll be all oily (are they tapped right through into the crankcase or are they blind holes?) so I think you stand a good chance with an extractor. Another way to get a snapped stud moving is to punch them round anticlockwise but not recommended on something so small and surrounded by nice soft aluminium...
I assume it has broken flush with the casing?
It's broken off slightly below the casing unfortunately, the threads on another one look dodgy too so I will replace that as well while I'm at it.
I was thinking maybe I could make a sleeve to protect the aluminium from the drill and center it at the same time ?
Tricky one with the engine in the bike.
Is there enough to grip it with a mole wrench? I guess not or you'd have tried that - maybe with a bit of gentle heat....
Normally I would cut/grind the broken stud flush with the case and then centre punch before drilling, starting with a small drill and then increasing.
A stud extractor might then do it but don't drill too much out or as you screw the stud extractor in it can burst the remaning stud and bind against the casing.
Keeping the hole smaller to avoid that can help however it risks shearing off the smaller diameter stud extractor - it's a bit of a black art.
This is all made much more difficult with the engine in the frame as you are operating upwards with restricted access and need to drill very accurately.
Wish I could be more positive but it sounds a tricky one.
Cheers,
Bernie
Quote from: berniej on 08 Mar, 2021, 18:26
Tricky one with the engine in the bike.
Is there enough to grip it with a mole wrench? I guess not or you'd have tried that - maybe with a bit of gentle heat....
Normally I would cut/grind the broken stud flush with the case and then centre punch before drilling, starting with a small drill and then increasing.
A stud extractor might then do it but don't drill too much out or as you screw the stud extractor in it can burst the remaning stud and bind against the casing.
Keeping the hole smaller to avoid that can help however it risks shearing off the smaller diameter stud extractor - it's a bit of a black art.
This is all made much more difficult with the engine in the frame as you are operating upwards with restricted access and need to drill very accurately.
Wish I could be more positive but it sounds a tricky one.
Cheers,
Bernie
It's below the face of the aluminium unfortunately, not only that but its broken at an angle.
Have had success with an easi-out type extractor in such cases but ideally you need a drill or electric screwdriver which will go anti-clockwise
Hi,
It is possible that the stud will be very stubborn so it worth applying some heat to break the bond the corrosion will have made. It is also possible that a previous owner has used a bit thread lock so again a bit of heat may help to break the bond before using the easi-out extractor.
Dave.
I just removed the other stud with the dodgy threads and there was some red thread locker on it, that said it came out easily. The broken stud is broken just below the surface by about 1mm, so in theory I should be able to grind it flat to get a drill started in the center without too much hassle. Even though it's right under the bike there is good enough visability.
Just out of interest how much oil is usually present in the crankcase ?
1/2 cup in theory.... 1/2 gallon if you have a wet sumper ;D ;D ;D
:) :) :)
I have recently done this very job.
What I did was: - Drain the fuel and pack some cloth around the oil cap to stop it running out. If necessary shove an old towel or something into the oil tank-- get some steadying blocks and with assistance, and lots of soft packing, lay the bike CAREFULLY on its side. If the broken stud is on the left side of the bike lay it on the right and VV. Not essential but it will give you an extra couple of inches.
Now the difficult bit. I drilled right through the stud as centrally as I could with about 3mm drill the I gauged how much off centre the hole was and enlarged it ( I think i was able to get about 4.5mm drill in without affecting the thread). Now you can use an easy out type of thing or a LH thread drill whatever. Drilling all the way through transferred a bit of heat the full length of the stud. Careful careful. Job done. Then I used allen bolts/screws to refit the cap.
It only took about half an hour so its definitely what I would do again.
Bestest luck
Mike 8) 8) 8)
Its worth tapping the tang of a file into the hole drilled in the broken stud and then use an adjustable spanner to turn the file. I had to do this recently and it worked a treat.
If it has broken below the surface, get a good set extractors that comes with guides for the drill. The guide sits in the recess, drill through it, extractor in and job done....maybe.
good luck, broken studs a common thing for me to deal with, I dont like extractors (despite having 5 sets of extractors, 3 different types). they are hardened and if they break, you are in deeper do do's than before. lean or lay down the bike to give clear access, centre punch on the middle of the stud and gradually drill bigger until it can be unscrewed, Left hand drills are available and I tend to use them. so , if the drill bites, its going the right way to undo.
one problem other than the hardness of extractors, is small ones tend to break and larger ones can swell out the stud making it harder to undo.
:) :) :)
Completely agree about extractors breaking off and of tightening effect
I spoke to my son who assisted me and he said we actually used the tang of a file a couple of years ago. So another recommendation .
Mike 8) 8) 8)
I considered every option suggested here apart from the file tang idea, but by the time i heard of it I had ordered a set of stud extractors. I will let you all know the result when they arrive, I should have them early next week..... Another possibility that I thought of ( If the extractor or file does not work) would be to cut a slot in the end of the stud with a dremel and use a screwdriver. It would damage the crank case a bit but I think it would get the stud out.
The stud extractors came today and I'm pleased to say that I have got the stud out without any damage. The first extractor I tried was not man enough for the job but the second one up in size did the trick, and from underneath the engine, it's a bit awkward but there is enough room.
The new studs I bought are completley useless so I used bolts instead, I think they do a much better job anyway.
well done, its that squeeky bum time when you are not sure how much further to take it before the extractor breaks.
as for bolts, I would stick with studs as if you have to take the sump plate off often , due to wet sumping, each time in and out can wear the thread.
Hi,
I agree with Chaz re studs if removal is often. Another option is to fit an aluminium sump plate with a removable plug with magnetic insert. The bolts will not have to come out as frequently so avoiding wear on the aluminium threads and the magnet will help to keep the oil a bit cleaner.
Dave.
:) :) :)
Personally I would go for the bolts and sump plate with a drain plug. Ultimately much easier in to drain etc.
Mike 8) 8) 8)
Quote from: Mike Farmer on 13 Mar, 2021, 11:28
:) :) :)
Personally I would go for the bolts and sump plate with a drain plug. Ultimately much easier in to drain etc.
Mike 8) 8) 8)
That is exactly what I am going to do. I can't understand why BSA did not fit them as standard.