Hi.
i need to change the top hat seals in the water rails. Yep you guessed one of the bolts shared. Any advice getting it out. It’s at the front of the engine on the A bank.
Rob.

 

Robbo
I have done exactly this too! After the panic subsided this is what i did:

• Drilled out the sheered shaft. This was not easy and I made a rather larger un-round hole doing it. The best way to do it (NOT the way i did it!) is to somehow flatten off the bolt shaft, then ding the centre with a punch, then buy a LEFT hand thread drillbit a hair smaller than the bolt threads external diameter and drill it out. It may come out leaving the threads OK, or it may not.
• If, as i did, you end up with a nasty shaped hole, then drill it out and tap it for a bigger size. You may have to drill out the hole in the water manifold casting a touch too. If you prefer, thread and tap the hole as mentioned and insert a stainless stud using high strength loctite. This means no more worries about sheered bolts. BUT, it does mean it is slightly more tricky mounting the water rail and manifold as you have to sort of get it down the stud at an angle and wiggle it into place.
• The bolts go through the head into the water jacket and are in the coolant. I used a stud because I was worried about the water-tightness of my hole, so I gunked up the stud threads good and proper and will not have to disturb it!

 

Thanks Greg.
I don’t suppose you know the bolt size as I need to buy a tap set. I assume it’s metric?
Rob

 

weld on top of stud a little tall weld so a nut can drop on it then weld that and the heat you make doing it makes it easy to come out.

 

Make that 2 bolts.

 

I haven’t got a welder. But good idea. Just thinking if I can borrow one off someone I know.
Rob.

 

Forget welding as they have broken off down the hole. Drilling out will be fine. Buy a tap and die set, they are cheap, and ally is easy to tap. Just choose a size that is just a touch larger than the hole. As you are re-tapping, the thread does not matter, it can be metric or imperial, whatever is easiest for you. Drill out first, though, then see what you have got to deal with!

 

Hi Robbo

Message from the GF's dad who is an Expert Welder, 'Don't put a Welding Set anywhere near it' as Steel and Aluminium expand at different rates and you could crack the block and wreck the engine!

He also suggested you get yourself a Set of 'Left Handed Taps' (ebay) for after you've drilled a hole in the Metal Stud like 'Greg' suggested, as they will bite in very tight and you may be able to unscrew what is left of the Stud (which is really just building on 'Greg's' idea a little bit in case you don't get any success with left handed drills)

 

Not left handed taps ( which are things to cut threads) but a bolt extractor, sometimes called an Easy Out. Personally, I have not had success using them. Normially, whenever I need to take out a bolt like that I use impact, never broken a bolt yet using that, but I've broken plenty using hand tools. Doesn't hep you now though.

You'd be ok trying to weld on a bolt on the end, you wouldn't put enough heat into it to crack anything. The differential expansion between steel and aluminium is exactly what you want to help break up the corrosion that is holding the remnant of the bolt in place. That piece it goes into isn't the block anyway. I'd try welding a bolt onto the stub end, then while it's hot put an impact wrench onto the now welded bolt and with any luck the heat and impact will break it free.

One alternative strategy is to use a Dremel or similar small grinder and grind a slot in the top of the bolt remnant, so a screwdriver can get a good grip. You may end up going into the aluminium a bit, but that's ok, it can can be sealed with flange sealer on reassembly. Then with a small tip on an oxy-actelyene torch, heat the steel bolt. A propane torch isn't hot enough. This is to break the corrosion bond. Somewhat counter intuitively, the hotter the flame the less total heat that goes into the whole piece. That's because you can get the bolt end locally very hot quickly, before the heat travels very far. Lower temperature flame needs to be applied longer, so it spreads out the heat more. Once hot, use a screwdriver bit in an impact and zip it out when hot. I've always had rust and corrosion break when at a dull red heat. In summary: have a helper at hand. heat as fast as possible, hand the torch off to the helper who has the impact ready to hand to you and hit the bolt with the impact before it cools too much ( and it will cool quickly).

 

Hello Robbo

Agree with Greg - you have nothing to weld to.
Regarding the drilling out - my biggest fear is what is on the other side of the bolt - if it is air, then drilling out is no real issues - if it is casting - then you don't really now how far to drill (but you can guess from the 2 unbroken bolts - maybe Greg can answer that point.

I fell for that years ago - and I drilled where a hole was not suppose to be.

The hardest part is starting the drill central. Usually when a bolt breaks off - it is slightly raised in the middle - which is exactly where you want to drill. It is also difficult to level - since it is broken past the top
If you do get a non-circular hole. you can use a heli coil instead of a bigger stud. Just another idea.

I have had success with the easy out - but only if I have a hole all the way through, I have had no success otherwise

Good luck

Cheers
Steve

 

It is air (ie the water jacket) at the end of the hole. My favourite still is a normal drill bit, but with a left hand spiral. But as JB said, spending time getting it started centralised is vital.

I have only has disasters with easy-outs that bite and then sheer making a bad situation awful! My advice is never use them!

 

Memory, HAHA, 8mm.

Easy Outs are banned anywhere near me or my cars.
They are only good it the broken bit is loose, and can be would out.
If that broken bit is seized, as these always are, they will snap off, and drilling an Easy Out, HAHAHAHA, not enough beer in the state to do that.

I drilled progressively, 6 of mine, and ended with a THIN shell of the broken bit remaining in the hole, then simply collapse that into itself with a FINE pin punch. Ran a thread tap for clean up.
All 6 took nearly 24 beers, so the actual memory is still fuzzy 25 years later. Mid Summer, 46C in the shed.

TIME, PATIENCE is all that is needed.

HINDSIGHT

Gregs stud method is waaaay better.

 

Cheers Grant.
Avnew metric tap set is on its way and no easy outs.
Rob.

 

Goodo, but I dont see BEER on that order, maybe already in the fridge.

You will be fine, as those bolts on mine were NOT Hi-Tensile, so they drilled fairly easily.

I used a standard punch, that just fitted the hole, and tapped with a SFH, until I had a flat surface to centre punch.

 

I'll just throw this in the mix.

In/on what was bolted into an aluminum background, a steal bolt sheared off. Level with the background. I took a Dremel tool and cut a notch a screw driver could fit in. A good sized notch for a good sized driver. I was surprised to see that the strength of the steel bolt easily pushed back and out the slight steel and aluminum mix up/overlap that happened on the edge of where the steel bolt and aluminum background metal met,,, and the bolt turned out. If that hadn't worked I hadn't shattered my chances of a reverse drill bit and a center punch. The aluminum background that the bolt was threaded into scored a bit due to the size of the Dremel grinding wheel,,, but it didn't mean or do anything to the structural integrity of the back ground aluminum part.

I have tearful stories about easy outs,,, if I didn't learn in making the the first disaster when trying to remove a sheared off bleeder valve on a caliper,,, I definitely LEARNT it in the second! There are some things I DO that I don't like to POST, lol... Actually, Lots!

Two new front XK8 brake calipers later (and I can't drink BEER NO MO) I'm still feeling that helpless anger!!! No more "easy" outs for me, lolololololololol 🤣

 

One sorted. Drilled out and the hole re taped. Took about 3 hours I reckon. I will have a go at the other one tomorrow.
Rob.

 

Well done Robbo, sometimes it feels like nothing ever goes right with these cars and mines had me close to tears many a time! Stick with it pal.

 

Cheers mate. The other bolt is out and the hole tapped. Will put it back together tomorrow. Then have a go at the other side.
I’m thinking of using a smear of stag wellseal on the top hat rubbers and gaskets. I used this on my Triumph Stag when I had to replace the head gaskets. It was highly recommend by the stag owners club. The Stag has long been sold.
Rob.
.

 

While I think on, when I did mine I bought a length of stainless tube off eBay. I think it is about 19mm o/d but check. It was pennies compared to the usual suppliers and you have the benefit of stainless over galvanised. Another job the forum put me right on.

 

It's incredibly interesting that this thread should show up just as I am about to do the very same- shear off a bolt. Mine broke smooth at the deck of course. So I ground it and center punched, then drilled... working on it now, just had to post as it's such an amazing coincidence