Threaded bar/bolt removal - cylinder head

[CLD]

Good morning all

My friend has recently had a little issue recently with his BMW 530D (3 litre straight 6 turbo Diesel)
This happened due to a little water getting into the cylinder:


Following the removal of the cylinder head, two bolts that hold a bearing carrier for the vacuum pump have snapped. They have left about 4/5mm of the remaining bolt protruding with roughly 15mm still in the head.
Once I've finished at the doctors I will post a picture of the offending article, but how would you remove them?

Many thanks!

 

[Bsmith]

I would weld a thick washer on the protruding part of the stud, then a nut on the washer and screw gently back and forth until it's loose enough to unscrew it all the way. The weld heat helps.

 

[gordon stephenson]

X2

 

[123hotchef]

ouchie yes welding a washer and nut gets my vote too

 

[Davidcardiff]

Weld a nut to the but of stud left and gently easy it out

 

[ford34/2]

been a few threads on similar problem, this was one::

http://www.mig-welding.co.uk/forum/...ylinder-head-bolt-with-5mm-sticking-up.58532/

Stan

 

[CLD]

I've just looked st it for the first time and one is pretty much flush

 

[Screwdriver]

Build a nub of weld up before fitting the nut. MIG is best and the heat will help free it too.

S.

 

[The_Yellow_Ardvark]

EASY OUT!!!!!! EASY OUTS!!!!!!!!
Only joking.
Try with a pair of mole grips to wiggle it back and forth.
I have some stud extractors from Snap on, the socket type ones.
If not weld a nut on to it.
But why did they snap?

 

[Johnseat]

I would drill right through the bolt so that if something does snap then it can be hammered through.
For the flush one, drill through all the way, brazing nozzle with a tiny flame and warm the stud a little then knock a decent torx socket into, not a cheapo as they tend to snap.
Beauty of this way is that if the bit does snap then it can be knocked through or if it doesn't twist out then it's going to be a drill it and tap job with a possible helicoil as a repair.

As for the stud stuck out, weld a nut over the top and get in screwed.

I've yet to come across a broken bolt or stud that doesn't come out with heat.

 

[slim_boy_fat]

Beauty of this way is that if the bit does snap then it can be knocked through

Looks to be in a blind casting?

 

[Screwdriver]

I would drill right through the bolt so that if something does snap then it can be hammered through.
For the flush one, drill through all the way, brazing nozzle with a tiny flame and warm the stud a little then knock a decent torx socket into, not a cheapo as they tend to snap.
Beauty of this way is that if the bit does snap then it can be knocked through or if it doesn't twist out then it's going to be a drill it and tap job with a possible helicoil as a repair.

As for the stud stuck out, weld a nut over the top and get in screwed.

I've yet to come across a broken bolt or stud that doesn't come out with heat.

I have to do jobs like this all the time working on older motorcycles. The torx trick is great but if you hammer into a sunken stud, the threads expand locking it more firmly in the hole. As often as not, cylinder head studs after a certain vintage will have been over torqued and might even begin to fail while in service. Trying to unscrew a failing stud will snap it even if the thread is relatively free.

I agree heat is always the best method but you don't have to worry about concentrating it on either part. A hole will always expand more than anything inserted into it on the grounds that the hole is always going to be bigger to start off with. Any expansion at all and the fixing will loosen off. Luckily, aluminium also expands with heat at twice the rate of steel.

 

[500e]

All for a touch of Never Seeze alloy to steel lube

 

[normspanners]

Check the head bolt threads in the block CAREFULLY for cracks they crack slightly to the 'open side' when the head is put under extreme loading.

 

[Wedg1e]

I'd have a crack at drilling them out. Often the heat generated just by drilling can be enough to release snapped threads. If you're careful and can get bang on concentric you can get most of the metal out with a drill then the remaining shards of thread can be picked out. Worst case, Helicoil it.
I'd be a bit worried about the one near the corner if you welded to it and it was really stuck; the applied torque could break the casting corner off.

 

[fixerupper]

Yes ,Drilling it out is I guess the proper way has the op got the kit ?I think I'd use a bit of heat and then the mole grips on the one with a bit of stud sticking up .The one that has broken off flush I'd clean of any oil or whatever , find a large washer with same size hole as the stud, and position it over it ,weld it, and then a nut, fill the centre of the nut with weld ...say a prayer and wind it out .....slowly slowly ... the washer can prevent damage to the machined face........good luck ...jeff

 

[Screwdriver]

Drilling out is the last resort for when all else fails.

I'm not convinced by the washer either. Just weld a nut to the stud or to a small knob of weld on a flush or sunk stud and weld the nut over that. If you MIG it, nothing will stick to the aluminium and you want as much strength as possible as near to the surface as you can get it. I also typically try to get a spanner on it while the whole thing is red hot. This is especially true for stainless threads in aluminium which seem to grip tightly again once they cool.

 

[Stueeee]

I'd try the welded nut trick first on the sticky up stud, if it won't budge you can still lop off the nut and drill out the stud. I always use a left hand drill bit for this. Conventional right hand bits are always trying bury the stud/bolt further in; a left hand bit will usually spin the broken stud out once you've got any kind of hole down the stud. Obviously you need a pistol grip or other drill which is capable of running in reverse to use these bits. There are some listed here:http://www.ebay.co.uk/itm/Left-Hand...783722?hash=item3aafc14b6a:g:FXAAAMXQnFhTkapN
Tracy Tools in Devon used to sell very good quality LH bits, don't see them listed on their website today though.

 

[Bsmith]

Obviously you need a pistol grip or other drill which is capable of running in reverse to use these bits.

A longer vee belt in a figure 8 on a pillar drill? would rub where it crosses over but only to be used once or twice.

 

[123hotchef]

ha ha how did u manage that in the end