frisbee91

What are the recommendations for an extraction method, assuming I can't get it out with a screwdriver?

My plan was this:
1. PB Blaster penetrant/lubricatant soak for a few days
2. Center punch and drill the bolt (right angle drill with a new bit)
3. Use a helical style "easy-out" bolt extractor.
4. Ease the broken bolt right out of there

Any other recommendations or tips? Should I use a torch to heat the bolt to break any Loctite? Is a different style bolt extractor recommended?

I wasn't thinking this was going to be a big deal, but I don't do this sort of job every day. Now I'm starting to worry...



p.s. ordering a new bolt, idler pulley, and belt today.

Macster

I do not remember how the subject came up but I was talking to some Porsche techs the other day about removing bolts snapped off -- oh it was regarding having to break off the head of a wheel stud that the owner had lost the adapter to and how to get the remaining wheel stud out of the hole -- and I was told the techs prefer to use left-handed drill bits if one can't simply grasp the broken bolt with pliers if any portion sticks out of the hole or needle nose pliers of there's something to grasp. Oftentimes during the drilling the bolt will back out on its own as it heats up from the drilling and the force and vibration work to loosen the bolt in the hole.

Sincerely,

Macster.

logray

Easy outs should be called hard outs. Especially if the bolt is hardened and especially if you buy or use a cheap one! Next thing that happens when the easy out fails is you have an even harder material embedded in the stud. Not saying I haven't used easy out's before with success, but... I've had less luck with them than success.

PB Blaster is good. You can try the left handed drill bit (use a stop) and the second good idea was a flat bladed screwdriver. If the stud is flat topped, using a dremel you can use a tungsten carbide bit on slow speed and carve a notch for the screwdriver. In fact, that same dremel bit will eventually eat through the entire bolt. Once you're done drilling, if the threads are damaged likely you would need to helicoil or timesert it afterwards.

Patience and use slow speed on any drill bit you use. High speed will add heat which can be good or bad (more below).

Remember this is the engine case so if you mess up it is a big problem.

If you plan to try and turn the stud, you need to get as much purchase on it as possible. It doesn't look like you can weld something on top to turn it.

I would try without heat first unless you need it. Heat can be a double edged sword. You can anneal it or harden it. Which one you use depends on the extraction method you want to use (drill through or turn respectively). If you anneal when you really need to harden it's going to make it even harder to remove.

speed rII

Loctite will need only 150C (302F) to break loose. So heatgun might do the trick...

Just remember, one hotspot in othervwise cold enginecase can lead to cracks.
So be careful and take your time

aviography

Macster is dead on with the left-hand drill bit suggestion, you can get these at industrial supply houses and should be the first item to get if you plan to drill, get a few different sizes so you can be certain to really center the initial hole.

You may even find that the friction heat generated from drilling may loosen the LockTite sufficiently that the broken stud may just come out by itself when you progressively go up in size of drill bits.

I've used the left hand drill bit to take out small set screwes on control ***** on an expensive piece of avionics, I was lucky since the recess of the set screw helped a great deal to center the drilling process!

frisbee91

I agree it's a great idea. Thanks Macster. Left-hand drill bits ordered (and recieved already) from Mcmaster-carr. Waiting on the new pulley, bolt, and belt to arrive from Suncoast. I've also got a huge assortment of tiny grinders, carbide end mills, and punches to make sure I create a good spot to start my drilling.

Wish me luck on my weekend project.

pesuazo

Good luck, let us know how it goes !!

fpb111

If you have access to a lathe make a guide bushing to slide into the recess for one of the lefthanded drill bits to keep it centered.

logray

Is there enough room there with the frame and such to get a hand drill in there? I can see fitting a dremel no problem...

Here are the dremel bits I've always used for these situations (mind you a LH bit will not only drill through but can also turn out the stud whereas a dremel bit will just cut through the bolt):

http://www.dremel.com/en-us/Accessor....aspx?catid=72

In particular the 9909 to get it started and the 9910 to finish off the work.

(remember low speed).

IIRC that bolt is class 10.9, which means it is harder than standard grade.

frisbee91

Well, I'd rather be lucky than good...

After assembling all manner of implements (of destruction)...



I was able to remove the offending broken bolt using only PB Blaster and a stubby flathead screwdriver. I soaked it a few days and it came right out.

Thanks for the suggestion Speed RII!

Too bad my new pulley won't be here until Monday!

Stephen Tinker

Great to hear that you had a bit of luck with the problem - it must have been a big relief when the broken piece came out!!
Sounds like the bolt was backing out before the belt tension snapped it off - unlike mine which broke off while I was tightening it up......

Edgy01

You were so lucky! i'm pleased to hear of a successful outcome. That's a tough area to work in.

While in there, take a look at all of the come along wheels (to include the tensioner one) and see if their wear surfaces are smooth and not ridged from an alignment issue.

Barn996

Glad to hear of your success, now where are those parts?

frisbee91

Parts installed, car running nicely

But WOW, that new belt was a royal PITA to install! I had the tensioner pulley fully retracted, and it STILL seemed like the belt was 1/2" too short. I finally got it, but only after 45 minutes of playing with it. I ended up using one of those one-hand-bar-clamp/spreader to stretch the belt.

Also, I was surprised at how low the torque spec is on the idler pulley bolt. 17 ft-lbs is nothing. I'm guessing someone overtorqued the thing in the past.

Thanks all for the tips.

pesuazo

Glad it was all sorted out, very happy with how easy it came out, 'cause it certainly looked like a bear at first glance..