Started by Don Berg 20417, January 10, 2010, 11:05:34 AM

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Don Berg 20417

                    I just  finished  7 year restoration ON my 41 cadillac 6267 last spring after driving it this summer I let it set until last week 1-5-10 and now I have a small leak of coolant from the front of the water pump. What can I do to fix it without pulling the pump off the engine?   Don

Otto Skorzeny

I wouldn't mess with it. My guess is that it's been sitting around not being driven and combined with the cold temperatures lately things just contracted and started leaking.

Perhaps when you begin driving it again it will seal itself back up. If you don't want to take the pump off - and I wouldn't either - there aren't really any other options short of tightening the mounting bolts.

Since the engine was just rebuilt, maybe they can stand to be re-torqued. Don't over-do it.

I know you're not even thinking of adding stop leak to a new engine.

I would leave well enough alone if the above suggestions don't work.

It's 70 years old. Expect a little incontinence.

Ask not what your country can do for you, but what you can do for YOURSELF



Stop Leak won't do anything for a leaking water pump shaft seal anyway.  As Forrest says, driving it may well be the best thing for it.  Otherwise, if it is a small leak you'll have to live with it, or ----- bite the bullet.
Geoff N.
1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold - but still in the family
1950 Jaguar Mark V Saloon resto-mod - Sold
1942 Cadillac 6269 - Sold
1968 Pontiac Bonneville Convertible
1935 Glenn Pray - Auburn Boattail Speedster, Gen. 2

Doug Houston

This water pump has a grease fitting on it. You may find that putting grease in it could stop the leak. The V8 water pumps from 1936-48 are funny, in that they leak sometimes, but stop leaking when grease packing is added Thre may no grease in the sels now.

Even when you're running the car, you need to keep an eye on the water pump for leaks. Seal kits are sold for them, but as above, you may just need some grease in the fitting.
70-DeV Conv
41-Chev 41-1167
41 Olds 41-3929

Don Berg 20417

Thanks guys for the help. I will grease it and drive it in the spring and keep an eye on it . Thanks again.  Don

Bill Ingler #7799

Just to add to what Doug has said, if you add grease, use a hand gun and stop pumping when you first feel resistance in pumping. Continuing to pump after feeling resistance might cause premature seal failure and give you more of a leak than now.

Alan Harris CLC#1513

For what it is worth, when my 1940 LaSalle sits for long periods, the water pump will bleed a few drops of coolant around the shaft. When the car is in use, there is no sign of seepage.

The pump was rebuilt about five years ago and has gone about 2000 miles since. I suspect that this may be common, if not exactly normal.

If you want to grease the pump, genuine water pump grease is available at the Lubriplate website. Good luck

Jeff Maltby 4194

The other is the bearing seals of the water pump.  I have devised a way to rebuild the flathead water pumps so they don't leak and have done it on my pumps and about 25 others and so far no leaks and one has gone about 25,000 miles.

Frank DeCou

Frank passed away last year, so this is all the info I have. Someone should have his fix for you ?
Jeffo 49er chapter

CLC 1985
Honda Gold Wing GL1500

Whit Otis, 1188

Hi,  You didn't say during your restoration if you rebuilt your water pump using the old chevron packing that comes in all the kits, or if you used modern lip seals.  Sure, you can shoot some grease in there and maybe because the car sat for awhile it may not leak, but more than likely it will come back.  I'd drain the system and remove the pump and fix it.  I have written a complete step by step process on how to rebuild these water pumps using modern high temp and chemical resistant viton lip seals.  My first rebuild lasted 20 years on a car I tour with.  If you are interested, drop me a note and I will send you the procedure.  There is just no reason to put up with a leaking water pump what with the high quality seals available today.  Also, you will no longer use that crumby, waxy old water pump grease.  If you follow my procedure, you will lube it once and that will be the end of it.
Let me know,
Whit Otis
Whit Otis -
1941 6219D Custom
1941 6219D
1940 7533F
1948 6069X
1985 Eldorado Biarritz
1999 Bentley Arnage
2019 XT5
Drawing of AP Sloan Custom by Terry Wenger

Brett Cottel

Well, I take this as a wake up call guys! Get out there, start'em up and move those old classic's......what better fun to keep from leaking anyway! I know, I know, I'm a calif guy but you can at least start them up back east can't ya?
Brett >:D
1955 Cadillac Meteor Combination Coach
CLC #27535
Pic's at http://s981.photobucket.com/albums/ae293/brettcottel/


I just need to add my 2c worth since this has been something I have dread would happen ...

If your pump has been rebuilt with the original "style" of bearing and seal, it means that your grease nipple is still an important part of teh lubrication and redualr maintenece.

Since the day I started the restoration on my 346 engine I have been  warned NOT to apply too much grease presure to this particular water pump fitting. If you do, the presure could pop the internal seal and cause it to start leaking.

Some rebuilders (like the one I used) will do a slight modification to the shaft and install a new style bearing that does not require external lubrication. The nipple is still there and the pump looks 100% original...but the grese fitting is actually doing nothing..it's there just for looks.

I did mine a year or so ago..Okay I admit I haven't installed it yet...but the place I did it at,  basically garantees that it won't leak. The place that did mine is called the Flying Dutchman. and he specializes in these old pumps....very knowledgeable...very reasonable prices. But the price is most definitely more than a standard water pump rebuild. They were recommended to me by other 346 owners on this list. I

It never hurts to add water pump lubricant to the cooling systems of these cars that spend a lot of time "not running" in the garage.

Whit Otis, 1188

If you rebuld your pump with the original chevron style seal, you are asking for trouble.  This is a chevron type seal that was originally designed for linear actuators, not rotating shafts.  Anyway, the best way to guard against applying too much grease pressure to your pump is simply to take the grease fitting out of the pump and remove the spring and check ball.  When you grease the pump, and then remove the grease gun whip from the fitting, a small amount of grease will puke back out of the zerk and avoid trapping high pressure in the cavity.

That said, I would never rebuild a pump with this antiquated packing...

If you use modern up to date seals, you will still be using the old style bearing, which is fine.  Remember, there are two bearings in the pump.  The front bearing, located right behind the belt sheave, was a sealed bearing when the car was originally built.... that is, it receives no grease when you lube the water pump.  The rear bearing is actually a bronze bushing, and is a perfectly fine bearing.... and quite frankly, I don't know what kind of "modern" bearing you could put down the bore of the pump that would be sealed.  Even so, a sealed bearing in this area, were it available would really not accomplish anything.  Further, the bearing balls would have to be so small, I doubt there would be much of a service life to the bearing.  If you use modern lip seals, and the original style bronze bushing, you will grease the pump once and that is all.

The orignal style seals required that thick old waxy grease, primarily because the chevron seal lips wear out quickly (especially if you really apply the pressure to the grease gun.  This flares out the seal lips against the rotating shaft and wears the seal, and yes believe it or not can wear a groove in the shaft over prolonged use).  Most of the original style pumps leaked and as mentioned above the quick fix was simply to shoot more of the old thick grease in it.

Whit Otis -
1941 6219D Custom
1941 6219D
1940 7533F
1948 6069X
1985 Eldorado Biarritz
1999 Bentley Arnage
2019 XT5
Drawing of AP Sloan Custom by Terry Wenger