the flyin' scotsman

Exactly...........the broken bolt is busted way down there.

I'd do everything suggested with the other bolts heat and impact gun. Once the water bridge is off then we can determine the best coarse of action for the busted one; weld or drill/helicoil.

AO

I don't think there is enough clearance to get the water bridge out of there without removing the oil filler neck which requires removing the intake.

If it were my car and I didn't have time to take the intake off, etc., I'd fill the hole with penetrating oil and let it sit overnight.

Then I'd start drilling with a relatively small drill bit. Then I'd switch to a slightly larger left-handed drill bit. If the left-handed bit didn't grab it, I'd then proceed to drill it to the right size for the insert. I WOULD NOT USE AN EXTRACTOR/EASY OUT. They break too easily and then present a hardened piece of steel that is really hard to drill through.

Make sure you use some anti-sieze on the bolts. and don't over tourqe them. Stage one 7ft lbs. Stage two 15 ft lbs. Done.

blown 87

It can be done, trust me on this.
I have seen head bolts on big truck motors broken off four inches down the block welded out.

StratfordShark

Thanks Andrew. I thought I would use suggested methods in order which makes sense in terms of difficulty/risk of damage to broken and remaining bolts.

Bought small blowtorch today! Is there no end to the tools I've assembled in 4 years of 928 ownership?

As such my plan was to remove crossover first (using heat and impact on remaining bolts, though one is too tucked away to allow this and I'd have to say if it would turn with an allen key poked down there and grabbed at top). I then planned to lubricate and heat the broken bolt stub if enough was proud of block.

Your suggestion should logically be tried first, as it doesn't involve removing crossover (though a few posters seem to have managed to remove the crossover without removing oil filler/intake). At least I could use the crossover as a drill guide to make a pilot hole.

My concern though is that I would be drilling literally in the dark. I wouldn't know if I'd made a big enough pilot hole to allow follow up with left hand bit, though I guess I could feel around with a sharp probe.

Anyway it wouldn't do much damage to at least try drilling pilot hole, so I will try this first. If I manage to make a pilot hole then I'll fill the bolt hole with penetrant and leave overnight before trying the left hand bit.

Thanks very much for your advice.

Jadz928

It can be done, but it's really tight on the left back side. You may chip off paint on the intake.
Definitely need an impact with one of the "allen sockets" with the ball on the end. This allows you to come into the cap screw on a angle, which is necessary.

The bridge body requires pulling it out on an angle, with a slight jimmy here and there.

Oil filling remained in situ, thernostat intet cap came off (but don't know if it needed to).

the flyin' scotsman

What do you weld onto when the bolt is broken down inside the cylinder head?

Look carefully at the pictures; you'll observe the broken bolt is left rear (passenger) on the 1-4 cylinder head............its sealing the funny shaped red 'O'ring between the water bridge and the head.

I removed the water bridge this past winter without removing the oil filler neck/intake but its very tight. If any of the remaining 3 WB bolts break leaving a 'stud' above the head surface WB removal without taking the other parts off will be impossible.

Either way with the water bridge off and the broken bolt down inside the cylinder head drilling, tapping, helicoil may be the only solution.

blown 87

The broken off bolt.

Honestly, I never would have thought it was possible until I saw it done.

Different method used for bolts that are more than 3/8 below the surface, you use a stick welder, the slag keeps the weld from sticking to the sides, then you just fill the hole up, weld a nut on and back it out.

soontobered84

If for some reason, you do decide to weld a nut on the remaining bolt length, and If the person doing the welding is using an arc welder or any other welder besides gas, DISCONNECT THE BATTERY, THE LH COMPUTER AND THE EZK COMPUTER. Grave consequences can occur to the electronics if they are not disconnected.

AO

There are 3 short bolts and one long. I belive you tried removing the "long" bolt. That's a M8x70mm. The others are M8x35mm. Take your drill bit measure about 7cm up from the tip and put a piece of tape there. When the tape touches the top of the bridge you should be just about there. You should be able ti sight down the hole with a good flashlight.

Hope this helps.

the flyin' scotsman

I added a pic to my last post to show the water bridge removed with the oil filler and intake in place. It should demonstrate how little room there is to work.

BTW, yes that's a beer can on top of the intake

Good luck Adrian.

Stromius

Would there be any point to to just leave the end of the bolt in the hole, grind off 2 mm or so of the bolt, ream clean the threads and put the thing back? Should only be 17 ft/lbs anyway right?

AO

If it had at least 4-5 theads of bite... I might try that (in a pinch).

StratfordShark

But don't you need to know the depth of the threaded hole in the block? The 70mm would be from bottom of the threaded hole to the top of the bridge.

The broken bolt that came out has 49mm of shaft, of which (threaded portion 12mm), and the bolt was out about 5mm or so when it broke so I should hit the remaining bolt with 44mm of drill bit down the hole.

StratfordShark

Of course! the procedure can't work without the beer can <g>