Water leak at/near pump bolt hole? 1956 322 Nailhead

1

1stTime56Special

Member
This is my first 50’s Buick, a 56 Special, purchased at an estate sale; car sat for 15+ years. Got her running, but have a coolant leak.

It seems to be coming from or near the 2 bolt holes at the bottom of the water pump cover - the ones behind the fan pulley that are really hard to get to or even see. I can feel that the 2 bolts are missing from those holes. Dumb question: I assume bolts should be in them??!! These seem to be the smaller bolts; I see other bolts on the pump cover that appear to be larger.

So... if those bolts should be there, does anyone know correct size? And the easiest way to bolt them on?

Thanks in advance for any help!
 
The parts book isn't any help. It just says mounting hardware items are standard stock. It looks like the two smallest holes at about 11:00 and 5:00 positions are pilot holes for alignment studs in the timing chain cover. See attached photos of the pump and exploded parts view.

The fan blade, spacer, and pulley will have be removed to get at the mounting holes. Attached is a shop manual page giving steps for pump removal.

If some of the other holes are empty, the depth can be determined by probing with a small drill bit or screwdriver. This will give an idea of the maximum bolt length needed. Then sample bolts can be hand-threaded to determine correct thread pitch and length without bottoming out.

I would say remove another bolt and try it in the open holes, but that's not a good idea. The bolt may snap off due to corrosion. There could be broken-off stubs in the suspect holes. That would require pump removal to replace the broken bolts.
 

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Just remove and replace. Any water pump that old that has been idle and probably dry will not have a long life. At that time you will see missing bolts (if any) and deal with that. Most of the bolts go into a water cavity, so apply thread sealer.
 
Many thanks Todd for the detailed response and 322bnh for replacement suggestion. Can I do a water pump replacement by removing fan blade, spacer, and pulley, all working from above? I don't have the ability to lift car, so all work need to be done under the hood (or what I can get to sliding under car).
 
Yes everything comes out from the top. The only need to work from below is to open the petcock. Attached is the next page from the shop manual on the water pump. The worst that could happen is having to remove the radiator to drill out stubborn broken bolts.
 

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Ok, so it looks like the leak is coming from a rectangular hole on the bottom of front neck of pump - see the pic. What the heck is that hole? Supposed to be there? Missing something? Just wondering if it’s an easier/less expensive fix than replacing the pump.
 

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It's a drain hole and belongs there. Should the rotating seal leak just a tiny amount, maybe 2 drops/day, the coolant runs on out without getting into the bearing.

Yours has been leaking enough to be noticeable, even showing a rust trail. Probably will just get worse. It's time to replace the pump before water ruins the bearing.
 
You can reuse the attaching bolts except the 1/4-20 which if not twisted-off at disassembly will twist-off on assembly. Again, use thread sealer.
 
Thanks for all your ongoing help with this! Old pump is off, luckily no bolts broke. When comparing old pump to new, there is a small metal dowel in one hole of old pump (I assume for ease of lining up when bolting) but it is not on new pump. See photos. Any issue, leak-wise, not having it on new pump?
 

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It probably would work. If it were mine, I would put a dowel in the pump body like the original just to be sure. The gasket at that hole would have an open cavity into the timing chain cover and an open hole through the pump body without the dowel in place. Cooling system develops as much as 7-15 psi at 200+ F when running. So a weak spot in the gasket from the missing dowel might leak. This is a design detail the pump manufacturer missed.
 
The dowel is supposed to be in the timing cover...there are 2. Remove the dowel from the old pump and tap into the timing cover. Then install the new pump.
 
Thanks! Just noticed a difference between old and new pump. The new one has an outlet on side opposite radiator hose. See photo. Came with what looks like a valve that goes there. Is this a correct setup? Valve is correct there?
 

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Just go to your local hardware store, take the new pump with you, & get a 1/2" NPT (I believe that's the size) plug in the plumbing dept. If your unsure ask for help. Put some thread sealer on the plug to help seal the threads or the tape made for this kind of stuff. Again, ask for help if unsure. MANY bolts that hold the pump on go into blind holes. To check which ones are open to coolant use a thin screwdriver & poke at the holes. Ones that go through use some sealer like Permatex or equivalent..

Tom T.
 
Thanks Tom, I’m good with bolts but now I’m talking specifically about the large outlet in last photo (red arrow pointing to it) - it’s not on the old pump but is on the new one, and comes with a metal plug to block it. What’s that outlet for?
 
Just use the supplied plug and plug it. You did not need it before so not now. Pump was probably made using some universal parts in the casting. (never saw one like that --- where did you get it?)
 
Buick redesigned the 1957 water pump mid-year by adding an inlet port and hose nipple on the pump neck. The heater core return line hose was then moved from the radiator tank to this new fitting. This was done to improve heater warmup and reroute the hose away from front suspension parts.

Don't know what this feature is doing on a '56 pump. Have not been able to find a reference showing this port on an original '56 pump.
 
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