Screw extraction advice

[stphers]

Hi Markos

It is a 6 X 1.0 on those bolts, If I remember right they are 20 mm long Drilling it out to a 5mm drill bit is not a problem, after all, you are just following the original small hole that you first drilled ( RIGHT IN THE CENTER , OF COURSE ) The problems start when the first drillhole is off centered Then the sh**& t happens

Thanks, Rick

 

[Stevehose]

I drilled out enough to get a torx bit in there, bolt did not want to come out and I didn't want to snap it off. DId heat and plenty of liquid wrench. A no go. It's not my car so I'm going to leave it be. If it were mine I'd be more aggressive. Thanks for all your advice, most helpful!

 

[BarryG]

I always go to welding a nut on first , this usually works.

 

[Stevehose]

Welding is out of my league unfortunately

 

[adawil2002]

Bummer @Stevehose. No more room for a slot, eh?

 

[rsporsche]

aaaargh. i feel your pain Steve. i've been there - how much has to be removed in order to take the part off of the car? i'm not familiar with the tii intricacies

 

[Stevehose]

The Kugelfischer support is a component of the front timing cover - all one piece so not going there! Not a big deal, it is only a cover bolt so not critical.

aaaargh. i feel your pain Steve. i've been there - how much has to be removed in order to take the part off of the car? i'm not familiar with the tii intricacies

 

[Gary Knox]

Steve.

If you cut the slot to use a screwdriver, you might consider an 'impact' screwdriver for removal. The 'shock' will help loosen the bond once the penetrating oil (I prefer Kroil's Penephite) has been allowed to soak in (several treatments over several days.

Good Luck - tain't easy!

Gary

 

[m5bb]

There always the use of an insert if you can't get it out. That is what we did to the 2002 tii strut. They have kits for inserts that come with the proper drills to perform this operation. I looked at that area yesterday on my friends tii and although not great access a right angle drill would probably work for drilling out the broken bolt and using the inserts.
Here is a kit on McMaster Carr. Not sure of the thread pitch? https://www.mcmaster.com/91732a948

 

[Skiver]

Had same issue with water pump. Old bolt snapped off. After farting around getting it out, replaced it with new m6 bolts from bmw…. However realoem is wrong and says they are all 40mm but it’s wrong one is 35mm. So now the new one is f$&@ing broken off inside the bolt hole!!

 

[mulberryworks]

I wouldn’t trust myself to hand drill it out to 5mm. Correct me if I am wrong but 6mm is the other “major” diameter. That doesn’t leave you much margin of error. 4mm, sure.

@Stevehose,

If you have to go to the hardware store, get an M6 x 1.5 tap (I presume it is 1.5). You can use it to chase the threads when you are done. If you do get sideways you will eat into the bracket like butter. Retapping are the original size though might make it salvageable.

I bought a giant metric tap and die kit from HF. It is pretty exhaustive but doesn’t cover the whole car. For instance, I had to buy a separate M16x1.0 die for the threaded wiper shaft. Weird size, bolts that diameter are usually coarse.

For cleaning out threads you can use a thread chaser instead of a tap. They aren't tapered and so let you get to the bottom of the threaded hole. They aren't designed to create threads, just clean them so there's less chance of damage. They are quite a bit more expensive but are of high quality unlike some cheap taps that are easily available.
Thread Chaser vs Tap: A Difference Guide (breakingfreemediation.com)

 

[m5bb]

Had same issue with water pump. Old bolt snapped off. After farting around getting it out, replaced it with new m6 bolts from bmw…. However realoem is wrong and says they are all 40mm but it’s wrong one is 35mm. So now the new one is f$&@ing broken off inside the bolt hole!!

You should check the depth of any hole you are putting a bolt back into, measure the ones you take out or use a stick or something to check the depth. They way replacement parts are working from BMW I would order bolts from a place like Bel Metric. Much bettter quality and much cheaper and if you're not sure on the length you can order a few lengths to try carefully.
BTW anytime your going to remove bolts that have been there possibly 50 years, you should soak with PB Blaster or similar. They might not break then.

 

[burky]

When all else fails you have to drill out the bolt , ideally you grind the top of the bolt so that you have a flat surface , use a centerpunch , its critical that you drill the center of the bolt , start small 1/8 or smaller , work your way up untill you can start a tapered tap , use cutting/tapping fluid , sharp drill bits, you do not need to much downforce on the drill !

 

[boonies]

Good advice above re. checking depth and chasing threads. Now that you have to extract choosing a good extractor is important. if the extractor gets broken in the bolt that is another level of misery.

 

[Gary Knox]

One of the best mechanics on the Porsche 928 web site makes his own 'thread chaser'. Using a hack saw, he places three cuts at 120 degrees around the leading edge of the threads on a new bolt with same thread pattern as the OE bolt.. Saws at about a 45-60 degree angle, and until they are about 1/4 of the way toward the middle of the bolt. A bit of penetrating oil in the leading threads of the bolt before installing and removing it. This 'tool' cleans the threads very well. A new bolt, or 'chased threads' on the old bolt can be installed easily.

 

[bavbob]

Get over the age of 65 and when you snap a bolt you actually compliment yourself first, complain later.

 

[deQuincey]

Had same issue with water pump. Old bolt snapped off. After farting around getting it out, replaced it with new m6 bolts from bmw…. However realoem is wrong and says they are all 40mm but it’s wrong one is 35mm. So now the new one is f$&@ing broken off inside the bolt hole!!

i can not understand what you did to broke a shorter bolt in the hole
maybe you put a 40mm bolt in a 35mm long position ?
now i understand

show a pic of the situation to be able to help

if that is a relatively new bolt it will be super easy to extract (you just introduced it, so not glued to the thread, unless you used loctice or similar)

 

[Strato102]

Overnight some PB Blaster in the freezer and heat the surrounding area as much as you dare. Blast the heated area with cold penetrating PB Blaster?

 

[JFENG]

CRC Freeze Off, $10 at the local Autozone.

I’ve had much better luck w reverse spiral. screw extractors (eg LF thread) than the straight ones. 100% agree to drill as close to the root diameter as you can. Don’t use small diam cobalt bits free hand. They’re too brittle and are more likely to break off. Before you drill the hole for the extractor, whack it a few times w a light hammer (12oz) to break the corrosion bond.

 

[Bert Poliakoff]

A friend showed me a novel way to get a broken bolt out if you have room to work. Drill the bolt going larger with the bits until just a "shell is left of the bolt without going into the threads. Then take an awl or pick of some sort and knock it in between the shell and the bore of the hole, collapsing the remaining bolt into itself. It does work providing you can totally drill through the remainder of the bolt or screw and does save the threads.