Water pump blot snapped =/

[mimregi]

Argh.... maybe time to invest in a torque wrench...

Anyway, I was bolting on a new water pump, was very pleased with the seal, all was going well, when one of the bolts snapped. I probably wouldn't even be posting here except that it was one of the two long ones, (upper, thinner of the two long shaft bolts). Should I be concerned about this? When I removed the old one, it was missing at least one mounting bolt, and it definitely feels snug and secure, so I am not terribly concerned about the pump itself, I am just not 100% certain what else that bolt may be responsible for (I am guessing it is just extra security for the front engine cap...).

Anyway, is this something that warrants immediate attention?

[Ed]

On one hand it could be just fine. Stay sealed for years. Then on the other hand it could stay sealed for a couple of weeks. Then when your out in the middle of nowhere she will start to leak. You won't notice it until it's too late the engine will overheat and you warp your head.

If you have the time and some of it already taken appart I'd fix it now. While the rest of the bolts will still come out easy.

$.02

[JimmyZ]

Like Ed said it may or may not seal. Years ago I overheated my Z while racing someone. Apparently I had put too much sealer on the WP gasket and not torqued things down tight enough. The high revs helped blow a good portion of my water out.

The three bolts on the left side of the pump go through to the block. The other small/short bolts terminate in the front case. From what you've described it is one of the bolts on the left side of the case. There is a slim chance that you could leak water internally. (See case backside photo)

You might be able to limp on it long enough to take time to collect parts, gaskets and whatever else might be needed to fix the problem. (Assuming you're taking the front case off) Hopefully it broke off just proud of the block's face and all you'll need is vise grips. Perhaps you can avoid takign the front cover off and just use a left handed drill bit. Get a tap and chase the holes clean so that things go easier.

If the bolt has broken beneath the block's surface then a left handed drill bit would be better. Ideally you could use the front case hole as a guide while using a fabbed bushing to center the drill bit perfectly. You will be able to drill more precisely with the radiator out. The depth from the front of the water pump to the back side of the case is 2.92". (Assuming it is the upper left bolt closest to the alt bracket. This measurement may help you figure out where the bolt snapped at.

Good luck

Jim

PS

If WP sealing is an issue you might try drilling and tapping the current hole in the alum front case. This doesn't help the back side of the case seal but it nixes one problem for a while. I had to do this when my Z was a daily driver. The fix lasted for years before the new motor was in.

[mimregi]

Thanks both for the responses =)

Been a busy couple of days -- I changed the water pump, dropped in a 280zx alternator, wired relays into my headlights and tightened up my shifter. I had a few odd issues related to wiring and the alternator and whatnot, but relevant to this thread:

The bolt snapped deep inside, I pulled out enough to still have threads at the end of it. And yes, it was the top left bolt, the smallest of the long ones. I doubly appreciate the post because the left-most bolt (vertically center) most certainly does not go through the block... Also, your picture allayed my fears about the two smaller holes that had no blots (it looks as though that is ok).

Since I made the post, I did go ahead and mount and seal the water pump, but I haven't driven the car -- I started it and ran it for a bit, and it appears to be leaking a bit. It's possible that it was dripping from somewhere else, but I strongly suspect that I don't have a good seal =/

I'm going to keep an extra careful eye on the temp and drip, and only drive short distances for a bit, but I fear I won't be able to ignore this. I have never had to remove a screw like this -- when you say "left-hand drill bit" sounds pretty self-explanatory and straight-forward though.

Thanks for the tips, answers and pics -- I'll keep you posted =)

In the meantime, feel free to drop any words of wisdom on me...

-m

[JimmyZ]

You're welcome! I know what it's like to sweat. You should have seen my face when I snapped a head bolt.

Thanks both for the responses =)

I doubly appreciate the post because the left-most bolt (vertically center) most certainly does not go through the block... -m

Are we talking about the same bolt? I'm thinking it's the one closest to the alternator adjust bracket. (Viewed from front, it is the upper left bolt) If so then this one had threads that go into the block. This one snapped for me also. I tapped the aluminum front cover for an oversize bolt and got a good seal on the pump. This worked for quite a while with no internal leakage. (Leak inside front cover) Internal leakage could be an issue but it wasnt for my case.

Here is a link for purchasing left handed drill bits. I've never bought from them though.

http://www.mytoolstore.com/hanson/hanson.html

If drilling then you'll need to find a way to keep the drill bit centered perfectly or else you'll be doing a helicoil or tapping oversize into the block. Watch the depth when drilling so that you don't pierce the block and get into the water jacket. (Of course)

Hope this helps

Jim

[mimregi]

Sorry, let me clear that up: The one with the arrow in your pic is the one that snapped; the next one counter-clockwise (facing the water pump) on mine is not a long bolt. I got the impression from you that it should be? I wonder if what you described doing to your snapped bolt is what the previous owner had done to that one?Thinking over what you said, I think tapping the front case will be what I do as well, see how long that lasts me. I haven't driven the car enough to know if that will be necessary yet though =/

Happy new year! And thanks =)

-m

[AZ-240z]

I'll put in my 2 cents. I don't have my car here, but, as I recall, the bolts pass through a cover plate and then screw into the block. If you were to remove the timing chain cover plate, I think you will find that the thin bolt probably snapped off outside of the block. You will need to use a pair of vice grips to grasp the remainder of the bolt and unscrew it from the block. Trying to go through the cover plate with some kind of easy out is looking for disaster in my opinion, until you actually look to see what it looks like at the surface of the block. In the early days of the 240z with the metal fans, this was a very common problem when replacing water pumps gone bad with the use of these early, heavy metal radiator fans.

Hope this helps in your discovery of the easiest plan for a repair.

Dan