Broken Bolt - Water Pump Cover.

Today, I buttoned up the bike, and it warmed up, it was leaking around the bottom of the water pump cover. So, I replaced the o-ring with a new one, and snugged it down. I warmed it up, and it leaked again, but less this time. I snugged it down some more. The bolt on the bottom never felt like it was getting 'tight'. And then "tink", it snapped.

So, aside from trying to extract the bolt, I need to head to the Fastener Guy, and replace all the bolts. I'll have the originals with me, but I don't know what material to request. I have heard that stainless breaks easier. Any experts able throw in some advice on material and/or grade?

While we are at it, what's the best way to remove a bolt that snapped off inside the case?

All the case screws are metric grade 8.8. You can pretty much use anything you want: 8.8, 10.9, 12.9 or stainless. Strength isn't a big concern on the case screws. As for extracting the broken piece, that depends on where it broke. If there is any above the surface after you take the cover off, no problem. Broken flush, I would start with a 1/8 left hand drill bit. 6mm screw is 5mm solid (inside the threads about .198") so you have a little tolerance to drill it with 1/8 (.125" bit). The left hand bit will probably turn it right out as you start to drill.

So do you thing the leak is the cover or the shaft seal?

All the case screws are metric grade 8.8. You can pretty much use anything you want: 8.8, 10.9, 12.9 or stainless. Strength isn't a big concern on the case screws. As for extracting the broken piece, that depends on where it broke. If there is any above the surface after you take the cover off, no problem. Broken flush, I would start with a 1/8 left hand drill bit. 6mm screw is 5mm solid (inside the threads about .198") so you have a little tolerance to drill it with 1/8 (.125" bit). The left hand bit will probably turn it right out as you start to drill.So do you thing the leak is the cover or the shaft seal?

I have excellent luck with left hand drill bits as well. I have been using the cheap sets from Harbor Freight and haven't had any issues.

Sometimes if the bolt or stud is sticking up enough, I have slipped the next size nut over the stud and tacked it with my MIG welder to provide a new head and use a socket to remove. They usually screw right out. I think the heat helps break the bond.

Thanks for the help guys. The bolt broke-off (flush) where it enter the case cover (beyond the water pump). I gave it a tap with a hammer and a really small screwdriver. The moto-gods were smiling on me, because the damn bolt began to back out. So, about a zillion taps later the piece came out.

I'll be replacing all the bolts tomorrow morning.

Thanks again.

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