Water pump headache

[David H.]

As much as I hate to admit defeat, I am about to take my water pump and ditch it for a replacement.
I used a rebuild kit from CC and rebuilt it. I had no problems with the rebuild. It went better than expected actually. Everything went together without a hitch. (or so I thought)
I carefully installed the gasket to the back cover using plenty of sealer on it. (maybe too much?) Tightened it all down good and proceded to install the assembly on the block. I used gasket sealer to keep the four gaskets in place between the motor mount and the pump and the motor mount and the block.
I then filled the block with anti-freeze and checked for leaks. Nothing showed immediately. However, when I came back out the next day I had little green drips coming off the bottom of the assembly from what looked like the back cover gasket. It was hard to tell where it was actually coming from since you can't see behind it at all. I had to assume that the back cover gasket was leaking so I remove the assembly from the block and had to start over.
Well, I won't bore you all with the entire story here but let's just say that it has been back on and back off the engine three times so far and I can't seem to stop this leak. New gaskets all around each time has not helped. Tightening the back cover more has not helped. Filing the surfaces of the pump where they connect to the engine has not helped. Filing the surface where the back cover goes has not helped.
At this point I have to assume that the rebuild kit was not perfect and it is leaking somehow. Unfortunetly I discovered too late that the kit was made in China so the quality is probably not what it should be and the seal is leaking. I can't think of what else it could be. Has anyone used these rebuild kits from CC and had problems with them?
Although I am getting pretty good at cleaning things up and redoing gaskets etc, I am pretty fed up with it and just want to dumpster it and start with a new one.
Any suggestions on what I might be missing here would be much appreciated.

[Gary B.]

Re: Water pump headache

Water pumps use a carbon face seal instead of a lip seal. It's probably weeping coolant thru the faces of the seal and out the weep hole in the bottom of the pump. Face seals need to be "seated" in once replaced. Usually about a 10 or 20 mile drive is enough, or even 10-15 minutes at high idle. The carbon face seals need the antifreeze for cooling and lubrication, so don't try and run them dry.
On one of my other makes of old car, the water pump tends to start weeping some after it sits the winter. After a drive in the spring, it seals right up and if good for the summer.
Run the car for awhile, let it seat in, you should be fine.
Gary

[Dennis S.]

Re: Water pump headache

I ended up making my own gasket out of thicker material and used a liberal amount of sealant. So far...no runs, no drips, no errors.

[David H.]

Re: Water pump headache

Gary, if that is the case with mine, and it certainly seems likely that it is, what can be done about it until the car is ready to run. My car is in process of a total body off restoration and the engine will not be run for quite some time. However, I wish to put anti-freeze in the block to prevent rust build up. Will the leak close up after some time on it's own without running the engine?
Thanks for your post.

[Dan P.]

Re: Water pump headache

Find someone who has a pressure tester and pressurize the system. So you can determine exactly were the leak is coming from.You are dealing with two machined surfaces. so a minimal amount of gasket sealer is required .NOT SILICONE. GM makes a great sealer PART #1050026 still available today.If you live in a big city there might be a place who still rebuilds water pumps .

[Joe L.]

Re: Water pump headache

As much as I hate to admit defeat, I am about to take my water pump and ditch it for a replacement.
I used a rebuild kit from CC and rebuilt it. I had no problems with the rebuild. It went better than expected actually. Everything went together without a hitch. (or so I thought)
I carefully installed the gasket to the back cover using plenty of sealer on it. (maybe too much?) Tightened it all down good and proceded to install the assembly on the block. I used gasket sealer to keep the four gaskets in place between the motor mount and the pump and the motor mount and the block.
I then filled the block with anti-freeze and checked for leaks. Nothing showed immediately. However, when I came back out the next day I had little green drips coming off the bottom of the assembly from what looked like the back cover gasket. It was hard to tell where it was actually coming from since you can't see behind it at all. I had to assume that the back cover gasket was leaking so I remove the assembly from the block and had to start over.
Well, I won't bore you all with the entire story here but let's just say that it has been back on and back off the engine three times so far and I can't seem to stop this leak. New gaskets all around each time has not helped. Tightening the back cover more has not helped. Filing the surfaces of the pump where they connect to the engine has not helped. Filing the surface where the back cover goes has not helped.
At this point I have to assume that the rebuild kit was not perfect and it is leaking somehow. Unfortunetly I discovered too late that the kit was made in China so the quality is probably not what it should be and the seal is leaking. I can't think of what else it could be. Has anyone used these rebuild kits from CC and had problems with them?
Although I am getting pretty good at cleaning things up and redoing gaskets etc, I am pretty fed up with it and just want to dumpster it and start with a new one.
Any suggestions on what I might be missing here would be much appreciated.

David------


You need to determine for certain where the leak is originating from. If it is the weep hole, then you know the leak is caused by the shaft seal. As others have mentioned, these will leak a little, especially when new (that's why the weep hole is there in the first place).

If the leak is actually originating from the rear cover, that's a whole different story. In that case, though, the waterpump shaft seal has absolutely nothing to do with it, whether it's Chinese-manufactured, or not.

A tip: if you are using an original style "flat" rear cover, these are notoriously difficult to seal.

[David H.]

Re: Water pump headache

Weep hole....ok, so if it was the weep hole it was probably good the first time around.
and the second and the third!
Well, my dad always said "the answer to any good question is a good education" and I certainly am getting that.
I just could not determine for sure where the leak was coming from. I think it must have been from the weep hole.
I will try once more with this one. I have filed the back of the pump and the cover with a fine file for a better fit and will use the gm sealer that Dan mentioned. I was using silicone on the block connection but 3m gasket sealer on the cover gasket. I will also see if anyone locally has a way to pressure test it before I put it back on.
I really would like to use this pump if at all possible and I think it should be possible.
Thanks for all the input everyone. This one nearly got the better of me.

[Michael W.]

Re: Water pump headache

A little late, but filing the mating surfaces usually does more harm than good. This action usually turns a flat surface into a slight convex making it that much harder for the gaskets to seal.

Find the exact source of the leak- it seems to occur while the engine is static, making it that much easier to find and fix.

[David H.]

Re: Water pump headache

Mike, Ya I know about filing being a not so good idea. The surfaces were pitted pretty good so I used a large flat single cut file that would reach across the entire surface and lay flat. I was careful to keep the file flat so hopefully didn't make it worse. I didn't take much off but was able to remove some of the pitting. Like I said, I'm about ready to dumpster it at this point and find a new one or at least a rebuilt one with the correct number on it.

[Gary B.]

Re: Water pump headache

David, if you fill the block with coolant, spin the water pump with a 1/2" electric drill, chucked on the pilot the fan locates off. Spin it for several minutes if you can.
Otherwise, find and/or borrow a pressure tester. You can pressurize the system with 12 to 15 psi, which might be enough to seat the face seals.
Doing both at the same time would be optimum.
Just do not run the water pump dry, it needs the coolant as a lubricant.
Gary

[David H.]

Re: Water pump headache

Gary, great idea with the electric drill. I will do that for sure. I dont know how to pressurize the system without the radiator connected. Is that possible? I have decided to give it one more attempt with the original water pump. Thanks to all for your input.

[Michael W.]

Re: Water pump headache

David, I don't think spinning the pump will develop much pressure at all. The normal operating pressure in an engine comes from the expansion of the engine and coolant when heated to operating temp.

[David S.]

Re: Water pump headache

David,

Is your backing plate secured to the water pump using screws or bolts? I know in 66/67 you sometimes had slotted screws. I had a similar problem with those and ended up taking a regular screw driver type attachment with a ratchet to properly torque. Obviously, it is a difficult situation with bolts holding in the backing plate.

-Dave

[David H.]

Re: Water pump headache

Thanks David, but my back plate is held in with the orginal bolts with the 7/16 head. I tightened them as much as I dared without breaking them off. Another thought I had was did over tightening at some point distort the metal around the bolt hole like it might do on a valve cover or pan cover. I made sure that area of the cover was flat and not distorted.

[Domenic T.]

Re: Water pump headache

Dave,
Sounds like your all used up with info but I put about 20 lbs of air in the pump to test for leaks while on the bench. As mentioned in the other post you can do it on the block. With a regulator, air, and a little engineering you can yourself in the garage.
Over tightening will only increase the chances of a leak. I use a nut driver with the 7/16 socket and tighten it first and after a few hrs of letting the gasket take a set I go back and do it again and again untill I put a wrench on it for final torque. THEN let it sit and check torque again followed with a pressure test.

DOM