StratfordShark

Photo is of remains of the bolt at rear right of coolant bridge — it snapped off there almost ten years ago, but I haven't removed bridge since and was not experiencing coolant loss. Now I'm doing intake refresh I have new bolts and gaskets for the bridge (I also need to get hold of paper gaskets — seems my MY91 had these installed at factory along with the usual rubber seals at the heads).

All the other 3 bolts came out with no problems whatsoever.

I was hoping that with no pressure from bolt head, the remaining shaft would be easy to turn out but it's really stuck there (why the bolt twisted/snapped there all those years ago). I tried a fluted Irwin bolt removed but it won't bite into the shaft and just spins on it.

Access is excellent with the bridge off, and there's quite a good length sticking out (more than seems in photo). I could try dremeling slot in it, but if the shaft is so stuck/corroded I'm not sure it will turn out with screwdriver anyway, and I don't want to get metal filings near the no 1 intake and the coolant header, though they are plugged with paper towels.

Should I try welding a nut onto the shaft? If I tried that would the LH and EZK ecus need disconnecting (battery ground was disconnected at start of intake job).

Thanks for advice.

drscottsmith

We ended up trying several different things (heat, soaking with kroil). The trick that worked? A small pipe wrench - working a bit at a time. Although the heat and kroil helped I’m sure.

-Scott

Koenig928

I've used that Irwin bolt extractor before too, try to find a socket head with a smaller diameter that'll bite the remaining bolt shaft.

I would soak it first with penetrating oil, then apply some heat at the base to expand the aluminum when you try to remove it.

C531XHO

Hi Adrian
I had a stuck bolt on my 944 twixt head and block. I tried heat and PB blaster etc but couldn't shift it. Tried drilling out the centre with increasing diam cobalt drills then easy out but ended up splitting the casting b***er. If I were doing something like this again, I would either drill more (and even consider drilling out and putting in a helicoil or somesuch) or now I have a welder, welding on a nut. Can't answer the question about the modules but presume disconnect would be prudent - others to chip in with own guidance

D

StratfordShark

Thanks I’ve always had success with welding on nut so I’ll try that after one more go with bolt extractor (found suitable size in another set I had) in conjunction with some heat as suggested.

C531XHO

I agree. I know the casting detail is different but I couldn't believe how soft Porsche blocks can be. This is why i would go welder to avoid this...

Mrmerlin

weld a nut onto the stud and remove it
NOTE drain the block first the coolant will suck out any heat thats applied

Kiln_Red

I use Stan's suggestion wherever possible. I have always had great results by doing as he suggests to remove a broken bolt or stud.

Then again, I don't handle many broken bolts anymore since using this product. Hands down the best penetrating oil I have ever seen, though it may be tough for 928 owners to get their hands on without access to a dealer. I would rate this as at least 500% more effective than PB Blaster. If you use PB Blaster first, then apply this, you can observe the latter product displacing the former on its war path to the corroded threads.

No affiliation.

AirtekHVAC

If there is enough thread length, could you die clean the exposed top, and put 2 nuts on it, in a locking arrangement, and then you won’t have to weld, just crank on the lower one with a wrench....heat/PB, acetone/tranny cocktail, etc, would still be required, I would expect...

StratfordShark

I wanted to try that approach and found nuts of correct thickness to fit the stub. But I don't have die to clean up the stub, so the nuts won't wind on!

Thanks for idea though.

StratfordShark

This isn't going well. I am able to now thread nuts onto the shaft and leave a small well, but every attempt to weld the nut to the shaft ends in failure, with the weld not holding to the nut or the shaft. Must be my technique/preparation so I'll look into the correct way to do this. I've succeeded with this before so not sure what the problem is.

Kiln_Red

Turn up the voltage! Don't run the nut down flush. Just 50% or less. You should have to stop for at least one cool down before you're able to have the puddle fill the hole. The entire nut should be glowing red after it's welded. Leave it to cool for a few minutes before attempting to turn out the broken bolt.

StratfordShark

Welding did the trick, after a few attempts where the weld kept fracturing. What worked in the end was dropping an M10 nut over the M8 stud, and welding at an angle around the inside of the nut to get decent penetration. Couldn't believe it when it turned out — very stiff at first but all came out ok and I could spin it out by hand for last few turns.

C531XHO

Well done chap. Looks like you had a late night in the garage judging from your post.
D

Mrmerlin

I suggest to clean the threads and use some PTFE pipe non setting sealant on the bolt threads this will keep liquid from entering and corroding the bolt back in the head
the same stuff can be used on water pump bolts