Thanks for all the continued advice guys. Ha! Yes, you're quite right Bill. I can't begrudge GM for making it the way they did and a bolt snapping years and years later. So my plan at the moment is to not remove the pump completely. I have a right angle adapter for my drill and I am getting some left handed drill bits, which might pull it out. I will take out the fan, clutch and shroud to give myself some more room.
LH drills are cool! Youll still need to bump a "center" for starters and a 1/8" pilot just for cutting the steel part. A RH bit is fine for that. When youre going LH, (probably 3/16"), use some heat and make sure the exposed threads (if any) on the backside are clean too. Run the drill slow. Try to go in straight. Once it walks off center, its gonna rip through that aluminum like butter! Is there any of the broken bolt "proud" of the surface, or broken just below. If its above (proud) youll need to rely on a center punch. File the broken end somewhat flat and start with a spring loaded punch, then a hammer punch for a good starting point... Bone up on that "Francais". You may also be able to make a drill guide with a piece of steel; drill the 1/8 and 3/16 holes and use vise grips to clamp it flat against the pump face. ws
Thanks Bill. I've got some new centre punches for that purpose. I also got some spring loaded drill bit guides, usually used on hinges: https://www.screwfix.com/p/hinge-drill-bit-set-3-pieces/6163v
Oh and no, none of the bolt showing. You can see in the video how it has broken off inside. There is a bit of the bot showing the other side. Thanks for the tip about cleaning it off. Shall I grind that down with a Dremel?
Sure... thats less to get out through the hole! Use a small cut off wheel on the dremel. Dont try to grind it flat. Thatll give you some "flashing" to have to pull through as well. You may get lucky and just run a RH bit through and have it come out the back side. Grab it with vise grips and reverse the drill. It should come right off. We call those hinge drills VIX BITS. I use them all the time. Those would be ideal for making a good center drill point, or continue al the way through. Im not too sure of the quality of the drill bit though. If you trim the back side youll only need to penetrate about 3/8" anyways. That was one of the reasons I asked if the stub was below, or proud. Being below that VIX BIT should get you spot on. I wanna see pics of the back side of the stub once its out to see how well you centered it! ws
Hey guys, I just wanted to update you on my progress. So in short, the bolt is out and the day is saved! Although, it took me nearly 2 days lol!! I actually started filming it but got so engrossed in it that the footage is not too useful. I might do a summary video incase anybody finds themselves in a similar situation. I started by purchasing brand new, titanium coated drill bits. If I did it again, I would probably go for solid cobalt. I did not get left handed bits as the bolt went all the way through to the other side. I used a lot of penetration spray and left it overnight before starting. I used a brand new centre punch to punch the hole. A few taps to centre punch the broken stub. I then used my hinge drill holder and started with a 3.5mm drill bit as that was the biggest bit that would fit in it. I started drilling through and it worked it's way nicely through the broken bolt. I was pleased that the drill bit came out right in the middle of the bolt the other side. Unfortunately the bolt did not budge. I then went up a drill size and started drilling through, then SNAP! Drill bit broke off inside. On reflection, my fault - I went up sizes to quickly, I think I jumped 1-1.5mm in size. I didn't use any cutting oil. I tried for an hour or so to work out the drill bit or the bolt with a centre punch but with no luck. I even snapped the very tip of a centre punch in there - Ahh! I set to work on the bolt the next day and decided to try and work a drill bit from an angle to try and remove some material from the bolt stub. I used cutting oil and worked the drill bit in at an angle, getting it behind the broken bit. I also used a centre punch to whack the drill bit through. This went on for about 2 hours until eventually, the punch whacked it through the other side of the bolt! I then used cutting fluid and went up extremely carefully in 0.5mm increments. I worked all the way up to 6.5mm which was the closest I could get to tap the hole to 5/16-18. I tapped very carefully and it tapped through fine. Now all ready for a fresh, brand new bolt. And it's A4 stainless
Bravo dude! All that LH stuff above was intended to be used on a blind hole bolt. Not even thinking that the bolt in question a through-hole. ws
