I changed a waterpump a few months back and in the process snapped a bolt off. I should have figured out the right way of doing things back then but I was under pressure to get it back on the road and tapped in a stud for it. But I did a sloppy job and the stud screwed into my threaded hole slightly skewed. It was the drill hole that was at fault. I freehanded the drill in making the hole. But I was able to work the water pump flange over the stud and tightened it all up. I torqued the repair stud by feel instead of to recommended torque.

Now I have a small leak. I've lost perhaps 4 cups of coolant over the last 4-5 months. Who knows if it's been progressively getting worse. I'm worried about it. But I have to take a road trip after next weekend. So I see my options are:

1) Leave it for later and risk it becoming worse and possibly breaking down on the road. Fix it when I have ample time to handle the job.

2) Get a shop to fix it. I don't really have the money. Especially when they could tell me that I need a new timing cover piece or the piece the pump bolts to, whatever that is called. Sounds like I'd have to do the head gasket again to replace that componant = Time or $$$

3) Go ahead and start fixing it immediately. To do this I need to feel confident I can drill a perpendicular hole. I don't have much tapping experience (thus the original problem). Is there a tool that allows for a perpendicular hole when drilling? I've thought about looking for some sort of tube that would snugly encompass the drill bit, that could be attached to a flange by a weld that would ensure the correct straight on angle. I imagine that I'm going to have to go to a significantly larger thread size to make up for my previous mistake, possibly, I fear, too large for the thread casting to accomodate.

Any help or thoughts would be much appreciated.

Paul

 

Ah, I might have thought of a solution. I'm going to look for a thread repair product to push into the hole and then start again.

I'm going to make a jig with my drill press. Got the idea when I saw an ad for a dowel jig. Same problem, so the solution is similar. I'll just make sure I have a block of wood with a true surface and drill press away. Hope it works.

 

Helicoil?

 

There are jigs (guides) you can get for drilling and tapping at a 90* angle. I have some very small ones made for drilling a gun barrel for a scope mount. (one wrong hole and the gunsmith's customer is rather pissed you screwed up his gun) They basicly have a piece that fits the drill size tightly but it rotates inside the guide part.

That being said I think I would drill out the broken bolt/stud and helicoil it. Probably need to use a 90* angle drill too. But you're right you still need to drill straight and tap straight LOL. For me the hardest part is usually getting the drill started in the center of the broken bolt, a center punch helps a lot.

 

I used a snake drill extention in a simular situation. But as stated above, the challenge would still be to get that perpendicular drill.

 

x2 on the helicoil

 

well it sounds like you messed up on your drilling, do you have another form of transport? you need to take it apart again, and either get a new cover or have the old one tig welded so you can re-drill the 90 degree perpendicular hole.